23 September, 2020

Growatt Sungold 3000 Failure & Repair

I'm documenting this primarily for my own purposes, should I need to do this again at some point.  I'm also doing it to share the information, since it might help a suitably qualified individual repair one of these inverters.  This repair and testing isn't to be attempted unless you fully understand all of the risks.  You could end up being electrocuted if you don't take the necessary precautions.  An RCD won't save you if you mess this up.

Let's get into it!

"No AC Connection" it says, innocently enough.

It's lying and withholding information about the horror that has unfolded inside.

There's a 20A, 3AG HRC ceramic fuse, near to where the mains enters the power board.  It's blown.  

One instinctively looks around to find the actual inverter circuitry (the H-bridge), quietly hoping it's not an expensive pre-made inverter module.  Thankfully, it wasn't.  Just a heap of mostly discreet components combined with four IGBT's to form a H-bridge.  So, it's serviceable at the component level, which is nice.

There's a skid mark across part of the PCB down there, where one of the small transistors has pooped itself.  There's another one with the top blown clean off.  There's multiple burnt and otherwise damaged SMD resistors and a couple of damaged but still functional ceramic capacitors.  At this stage, I pretty much know what's happened.  At least one of those IGBT's has failed short and/or exploded and the gate pin has lost it's insulation property (that's the I in IGBT).  That's a problem, because the IGBT's gates are generally fairly low voltage - 15-30V, but the IGBT itself can often be switching voltages in the hundreds of volts.  In an inverter like this, it could be switching 500V, since that's the maximum voltage the inverter is rated for - but you'd be ill advised to run it anywhere near that.

There's four FOD3120 devices down there as well.  They're gate drive optocouplers for the four IGBT's, but there's a problem.  The isolation barrier has been compromised and some of the low voltage circuitry has been damaged.

There's a rectangular cut-out in the PCB where a couple of wires go to a thermistor attached to the heatsink under the power board.  There's quite a decent black mark down there as well.

H-Bridge Circuitry (damaged):

Second hand units on Gumtree?  Not at the moment.

Schematics available?  Couldn't find any.

Continuing the diagnosis then.  The path the current took via R51/R51A leads back to a low voltage power supply.  Everything there looks physically intact and everything checks out OK with a multimeter, so that's good news.  The logic board still works when there's power from the solar panels connected, so I'm thinking it might have a chance of being repairable.

Since the low voltage power supply also supplies power to all of the FOD3120 optocouplers and is also used for driving the LEDs in those optocouplers, they're possibly all damaged.  Tracing back where the LED side of the optocouplers are driven from leads me to the logic board, as expected.  There's a ULN2003A there, near the IDC header.  Poking around the ULN2003A didn't reveal any obvious damage, but I started the repair by replacing that chip, not taking any chances.   I had them in stock, since they're about as common as dirt.

I then went about identifying all of the components in the H-bridge circuitry.  Since it's a H-bridge, the "high" side and "low" sides are duplicated.  Thankfully, one high and one low section of circuitry survived, and due to this, I decided to commit to doing the repair, since all of the damaged components were going to be identifiable.

Components were ordered and the repair was done.  I replaced every component in the H-bridge circuitry and some others as well, mostly being cautious.  I'm $120 in and I've spent the best part of a day on it.  I don't want to see my efforts go up in smoke.

Repaired H-Bridge Section:

Note: If you look closely, you'll see all of the 20R0 resistors were replaced with 39R0.  There are two 39R0 resistors stacked on top of each other, but you can't see that in the photo, so they're actually 19R5 now.  I somehow forgot to order the 20R0 resistors but had the 39R0's in stock.  You can also see where I've replaced one of the 200R resistors with a leaded type, as I couldn't source any suitable 200R resistors in that size.

Bench Testing:

It was time to think about bench-testing the inverter.  I wanted all of my testing to be current-limited, in case something went wrong.  I didn't want to connect the inverter to the grid for testing purposes, nor did I want to put ~330V DC across the PV input terminals and hope that didn't end badly.  I also don't have solar power here, so the smart meter detecting anything that resembles feed-in had to be avoided, so that rules out connecting it to the grid via a ballast of some sort.  I'm not sure how I'd explain a feed-in event to the power company.

The bench test setup was using the isolation transformer in the schematic below to do the current limiting.  It's a 5A isolation transformer with a suitable fuse installed.  In future I'll be using a 100W electromagnetic ballast to limit the current, so it's included in the schematic, but wasn't actually there when this inverter was tested:

The variac was used to slowly ramp up the voltage and to cut off the PV feed-in to the inverter when the output current of the PV inverter got too high.  Photovoltaic panels are isolated from the mains normally, so an isolation transformer was also used.

The next thing to do was emulate the grid to trick the inverter into thinking it was grid connected.  I gave this a bit of thought and decided to risk killing a pure sine wave inverter by back feeding it a little. I had a Mishto 2500W/5000W inverter that I never use sitting in it's box, so used that.  There were some scary moments, but nothing went bang (kind of surprising since back feeding such an inverter is asking for trouble).

My understanding of how grid-tie PV inverters work is that they raise the output voltage slightly above the incoming grid voltage, and by doing so are able to feed into the grid.  This meant that the PV inverter was going to try to take over powering the test load if it could, and would probably be quite happy to back-feed the Mishto inverter and destroy it.

Using the variac, I was able to regulate how much current the PV inverter could put out, and thus keep the test load partially powered by both inverters.  It was a balancing act, and it got scary at times.  This is why I'd use a 100W ballast in future, combined with a test load over 100W, so that the PV inverter could never take over powering the test load completely.

Below is a diagram of the emulated "grid" side of the test bench setup:

The step-down transformer was used mostly to reduce the output voltage from the large 13.3A transformer feeding the low voltage side of the Mishto inverter.  Once rectified and when under no load, the voltage was too high and the Mishto inverter would indicate a fault.

Connecting the PV Inverter earth to the 240V neutral was done as the PV Inverter initially came up with a "PV Isolation Low" message.  This I feel is rather dangerous, since the metal chassis of both inverters is now tied to the 240V "neutral", which may not be safe to come in contact with.  Something I considered was instead connecting a 1uF X2 capacitor between the earth and neutral of the PV inverter, to again limit any current flow should something go wrong.  I never did it, so don't know if it would have worked to suppress the PV isolation fault message from the PV inverter (it won't start up with a PV isolation fault condition).

Test Bench Setup:

I'd like to find a way to protect the Mishto inverter from being back-fed, but haven't been able to think up a solution to that so far.  If you think you know of one, feel free to clue me in.

Component Values:

Here comes the useful information if you've got the skills to do this level of component repair.  Since there isn't a schematic diagram available at this time of writing, I've made a list of every component in the H-bridge circuitry, which I expect would be the most likely part of the inverter to fail.

I replaced some additional components out of an abundance of caution, since I didn't want to do this repair twice.  Not when it's costing $120 each time and risking damage to the main logic board, which could write-off the whole thing.  Until a schematic becomes available, I'd suggest you consider going the extra mile if attempting a similar repair.

Logic Board:

U2: ULN2003A (SOIC-8)

Power Board:

C43, C41, C47, C33, C35, C40: 220uF 25V LOW ESR (eg. UUD1E221MNL1GS)
C45, C46, C38, C39: 100nF 50V (0603)
D7, D10: UF1J (DO-41)
R64A, R64, R51, R51A: 20R0 (1206)
R61, R63, R71, R72, R47, R48, R53, R54: 3.3K (1206)
R57, R70, R40, R50: 68B (4.99K, 0805)
U5, U6, U3, U4: FOD3120SDV (8SMD)
Q15, Q16, Q13, Q14: MMBT2907A (Original Marking: 2E, PNP, SOT-23)
R38, R56, R39, R55: 100R (1206)
R46, R45: 0.02R (1206) *
R62, R60: 20R0 (1206)
D17, D19, D16, D18: UF1J (DO-41)
R52, R65, R49, R67: 47K (0603)
R41, R65, R42, R58: 200R (1W(?) Metal Film MELF) **
C37, C36: 220pF 100V (1206)
C42, C44: 470pF 100V (1206)
Q5, Q8, Q6, Q7: IXGH48N60C3D1

Other components I replaced as a precaution:

1x IXGH48N60C3D1 + FOD3120SDV
1x SPW47N60C3FKSA1
2x Song Chuan SCL-1-H-DPNO 12VDC Relays (they both had worn contacts).

* These two resistors are probably just zero ohm links, but the originals were unmarked.  As the original resistor that survived measured around 0.02R, I replaced them with 0.02R resistors (P/N: PF1206FRF070R02L).  I also checked the original component for inductance, but it wasn't measurable.

** R42 was damaged slightly.  I couldn't find a suitable replacement, so replaced it with a 200R Vishay PR02, and turned it into a surface mount resistor by bending the leads tightly under the resistor and cutting them short.

20 July, 2017

Motorola MC68705R3P EPROM Copier / Reader

I needed to copy a MC68705R3P chip and needed to build some hardware capable of doing this.  There is an old project around dedicated to that, but the design is old and after looking at it, I decided it'd be easier to accomplish more modern electronics.

Below you will find information regarding my copier, which also doubles as a programmer, but it's still a bit clunky and needs refinement.  That said, if you're interested in the firmware for it, the source code can be provided.  Once someone shows some interest in the project, I'll probably devote a day or so to making up the schematic diagram.  That said, analysis of the firmware would likely give you enough information to make your own.

If you happen to be into MCU glitching, specifically for the purposes of firmware recovery, I'd be happy to hear from you.  Even if you'd just like to share your experiences, that would be appreciated, as I'm rather interested in the subject and would like to get into it somewhat.

My copier is based on an Atmel ATMEGA1284P.  Using the method that was discovered and documented by Peter Ihnat, I went about creating a copier using more modern technology than the copier I found here.

To understand roughly what my copier hardware does, please refer to Peter Ihnat's documentation regarding the method he found based on timing clock pulses.

My firmware for the Atmel ATMEGA1284P MCU is licensed under the BSD license.  You're free to do pretty much whatever you want with it.

Before we get started, below is an image of the first revision of my copier.  Using the schematic for the programmer circuit designed by Motorola and the information provided by Peter Ihnat, this is what I've come up with.

The circuit itself is fairly simple.  There is an 8-bit data bus running between the M68K MCU and the Atmel MCU.  There are 100ohm resistors inserted in this bus.  The reason for these was to provide some current limiting in the case that the M68K MCU didn't boot into programming mode and instead started to run its pre-programmed firmware.  I wanted to ensure that neither chip would be damaged in this case, as the Atmel chip will drain current and the M68K chip could potentially source current.  In the case where the M68K chip fails to boot into programming mode, the behaviour of that chip is somewhat undefined and unpredictable.  The circuit needs to take this into account to avoid damage to either chip.

The Atmel MCU is running at 20MHz, which provides it ample time to react to anything that the M68K chip needs.  An off-the-shelf Serial<->USB converter board is also used.  This helps with debugging and also provides a method to get information out of the Atmel chip, such as a firmware dump of the M68K MCU.

The disconnected wire you can see is a 1MHz clock signal that was intended to be connected to the M68K MCU EXTAL pin.  I'd disconnected the clock wire and replaced it with a 1MHz ceramic resonator as I was having problems getting my chips to boot into their programming mode.  It turned out that this had nothing to do with the problem.

Above: The M68705 MCU being copied is on the left, the Atmel ATMEGA1284P is in the centre.  You can also see that I have the ISP for the Atmel AVR connected to the board for easy firmware updates, and the USB<->Serial converter is also connected to another computer.

Regarding the problem getting the chips to go into programming mode, the problem was that the first chip I attempted to use was too defective (damaged) to boot into its programming mode.  The second chip I used contained the same firmware but was a mask ROM version and it wouldn't boot into its programming mode either.  This is probably because it's a mark ROM chip and likely doesn't have the bootloader code in it to activate the programming mode, since it would never need it.

Eventually, I got a third M68K chip and it went into programming mode first try.  I wasted quite a lot of time on this issue (days) but eventually got it figured out.  The main problem was that I was blaming myself and my hardware for the problem, convinced I'd somehow done something wrong.

Then there was another problem.  I could see that for the most part at least, my code was finally working.  I was able to see firmware data.  I was able to see some text in that data that identified the person who wrote the firmware I was trying to copy and the company that the firmware was written for.  At this point, I knew that I was mostly there, but just couldn't get the M68K MCU to verify that the code I'd retrieved from its EPROM was correct.

Resolving this issue, again, took days.  The main problem in this case was an assumption I'd made.

I'd assumed that it was very improbable that an engineer would design a chip like this and then require 4097 bytes of data to program the chip.  4096 bytes made much more sense, and I'd assumed that the documentation was wrong.  One night, I decided that I should figure out if I was wrong or if the documentation was wrong.  I changed my code to work up to the 4097th byte, not expecting it to reveal anything or even work for that matter.  To my surprise, it did work and another problem was solved.

That night, I finally got it.  The verified LED turned on.  The M68K MCU agreed that the firmware I'd fed it was the same as the firmware it was programmed with.  Finally, I had succeeded.  It took me much more time than I'd like to admit to get to this point.  All up, probably a solid 2-3 weeks of work.

Here it is, the green LED is the Verified LED.  The yellow LED is the Programmed LED.  All those other wires you can see are connected to a logic analyser.

This was a great moment.  Finally, things worked.  Better yet, the results were reproducible.  This was a small personal milestone for me, as I've been interested in "glitching" MCUs to reveal their code, and this, to me, is a small step in that direction.  This project will also bring a small financial benefit to me, being that it will enable to me repair some products that currently retail for $350.00 AUD or more.  Personal gain isn't the goal here, it's more about learning and a bit of geeky fun.


Going by the datasheet, the maximum programming clock speed is 1.1MHz, the minimum being 0.9MHz.  As an experiment, I removed the 1MHz ceramic resonator and re-connected the clock wire to the EXTAL pin of the M68K MCU.  I've been able to get the M68K MCU to work correctly at 5MHz, which means that getting a copy of its EPROM only took 5 minutes.  Unfortunately, running the chip at 10MHz didn't work out, but I was pushing the limits as it were.

The firmware contains pre-tested timing values for 1MHz, 3.33MHz, 5MHz and 10MHz operation.  At this time, the code will need to be re-compiled and re-flashed to the Atmel MCU if you wish to try out these alternative clock speeds.

The default build runs at 1MHz.  This is in order to give you the best chance of success and to conform to the limitations of the M68K MCU specified in the datasheet.  It would be trivial to change the code to allow a simple DIP switch selection for the clock speeds, should you wish to do something like that.

Alternative methods:

Something else that I've been thinking about is the fact that since I have control over the clock for the M68K MCU, I should be able to eliminate the timing-based code and instead count clock ticks to determine if the bytes are correct or incorrect.  Since incorrect guesses take more clock cycles than correct guesses do, it should be trivial.  It would also mean that I'd be able to eradicate the timing values from the code and work solely on clock pulses, at any frequency capable of being produced by the Atmel MCU and that also works with the M68K MCU.

If you are interested in the code or the schematic for this project, please leave a comment below.  I will publish that information if there is demand for it.

03 October, 2014

SUH DER SD83-A AC Synchronous Motor Teardown

In an earlier blog post I did a teardown of a TYC synchronous motor.  We found that it was made of entirely plastic gears and was a little lacking in the quality.

Today I received a new batch of SUH DER SD83-A synchronous motors.  I purchased them directly from the manufacturer in Taiwan.  I also had an immediate need to replace a faulty one.

What follows is the teardown of the faulty motor.  The motor itself and its gears were all in perfect condition.  Its not pictured, but the failure occurred due to dirt and dust getting caught between the motor output shaft and the bushing on the front of the motor.

The bushing is pressed into the front metal panel of the motor.  In my case, when the output shaft had seized against the bushing, the bushing itself started to turn.  So the motor still worked.  That is, until the hole in the front panel of the motor became unevenly worn and the motor could then seize up again.

You may notice evidence of tampering to the motor in the picture below.  I had opened this motor previously in order to get it going again.  Brute force was involved, and it did work again, but it was time to find a new motor.

Let the teardown begin!

Motor with front cover removed.  We can see a mix of plastic and brass gears.  The large plastic gear appears to have a steel gear that mates with the brass gear.  It seems they have decided that plastic gears are good enough for the low torque part of the motor:

Close up of the output shaft gear.  It looks like a brass gear with the steel output shaft pressed into it:

All gears have been removed, the motor output shaft is seen here, along with its plastic gear:

Metal cover removed.  The metal cover is pressed into the exterior motor housing:

Close up of the motor's rotor:

Motor stator (the purple thing - it contains the winding for the motor) and the remaining shell that the stator was sitting in:

Motor stator, insulating tape still installed:

Motor stator, insulation tape removed.  Beneath the wires appears to be masking tape:

All of the bits and pieces that made up the motor:

You can compare the construction of this motor with a cheap eBay motor here:

All trademarks are the property of their respective owners.

23 September, 2014

TYC Synchronous AC Motor Teardown

I recently ordered a couple of TYC branded geared synchronous motors, from an online seller based in China.

The plan was to see if they would be suitable for use in repairing Breezair dump valve assemblies.  It turns out that they are somewhat suitable, but really far from perfect for the application and the quality isn't great.

Long story short, I modified the motors that were shipped to me and tested them out.  At first, no problems.  One of the motors was too weak (not enough torque) and the other was looking good until the output shaft came out.

The shaft wasn't held in by anything at all.  It appears that it's just pressed 2.8mm into a hole in a plastic gear, as you can see in the images below.

While modifying the shaft was the cause of the failure, it prompted me to open one of these motors up and check out how it was made.  So, here are the teardown photos for anyone who's interested:

Motor, after the output shaft was modified:

This wasn't supposed to happen...

The teardown begins.  Top cover removed.  As you can see, this motor uses plastic gears.  I expected it would and as such I tried not to heat up the motor shaft too much when I was modifying it.  It appears though I wasn't careful enough.

Close-up of the gear assembly.  The large white gear is the one that the output shaft was pressed into.:

Gears removed.  You can now see the actual motor:

Metal plate removed:

Motor Stator (electromagnetic coil).  Under the tape there are two knots, one in each of the blue wires, to stop you pulling them out of the motor.  Under the tape is just a coil of magnet wire:

Motor Rotor (the bit that spins/rotates):

The rotor has been removed, teardown complete:

All of the bits and pieces that made up the geared synchronous motor:

Motor specifications:

AC 12V
50/60Hz 4W
2.5 ~ 3R/MIN

Which basically means, its a high torque motor, moves very slowly (approx. 2.5 revolutions per minute), and can rotate counter-clockwise (CCW) or clockwise (CW).  This mode is also known as "free", I guess since the motor is free to turn in either direction when power is applied.  The direction can usually be influenced by applying a pressure to the output shaft in one direction or another.  The motor should then rotate in the direction that is easiest for it to move.

The motor in this teardown cost $8.40 AUD inc. shipping.

For comparison, below is a link to a better quality (mostly metal geared) synchronous AC motor:

All trademarks are the property of their respective owners.

10 August, 2014

Suzuki Alto NSCR-06 Amplifier Specifications

A while back I was looking for the amplifier output specifications for the NSCR-06 radio/stereo used in the later model Suzuki Alto's (also sold as a Nissan Pixo), but couldn't find them.

The amplifier in this radio is a Toshiba TB2926BHQ.  It's apparently a 4x45W audio amplifier.

That means there are 4 channels and each channel is capable of delivering about 45 Watts.

Suzuki seems to use the same stereo in all of their later model Alto's, even in the cars with a 6-speaker sound system.  In vehicles with the 6-speaker sound system, the front right dash speaker and front right door speaker will be wired in parallel, and the same applies for the left speakers.  In the 6-speaker configuration, the speakers in the dash are only tweeters.

The factory tweeters look reasonable, but the speakers in the doors are junk (paper cone speakers).

In the models with the 2-speaker sound system, the dash has two paper cone speakers and no speakers in the doors.  Suzuki didn't even bother putting in the wiring for the door speakers, which is annoying.

As you've probably guessed, one of my cars is a Suzuki Alto (I own 3 of them).  The one I drive daily is a 2010 model, and it's the cheap model without any extra features.  I've installed some Sony Xplod 4" 3-way speakers into the dash.  No modifications to the dash were required.

The sound is much better.  I can set the radio on Max volume and there is very little clipping or distortion.  It can be quite loud and the music still sounds crisp.  The speakers cost around $50.00 AUD (model: XS-GT1038F) for the pair.  They were easy to install and no vehicle modifications were necessary.

On another note, I have my doubts that the power wiring in the car will be able to supply the stereo with all the power is needs to drive 4 speakers @ 45 watts per channel.  I might test it soon and update this article with my findings.

During another mission to improve the sound quality in the vehicle,  I installed Sony Xplod speakers into the front and rear doors.  The front speakers are wired in parallel and I decided to keep the Sony speakers I'd previously installed in the dash connected as well.  As such, the load on the amplifier in the stereo is probably about 2 ohms instead of 4 ohms on the front speaker channels.  I decided to take the risk.  If you read the datasheet for the power amplifier IC, it's a pretty rugged amplifier and it should be able to handle overload conditions as its own built-in safety circuits should kick in to prevent damage.

The additional speakers were a good improvement and overall it was worth doing.  The stereo will clip at about volume 42 when playing music from a CD, radio stations can be turned up louder before clipping sets in.  The type of music you're listing to also has an impact on the volume it'll be happy to run at.  If there is little bass, then louder volumes will be OK.  For instance, classical music can be listened to quite loudly, where as normal pop music will clip at about volume 42 due to the bass.

02 November, 2013

Breezair Icon EXH-130 Problems

Last Update: 20th December, 2021.


Repairs to my EXH-130:

Repair 1: The Motor
Repair 2: The Water Pump
Repair 3: Tripping Circuit Breaker
Repair 4: Another Motor Fault
Repair 5: Drain Valve

Other Repairs (not a complete list):

550 Watt Direct Drive Motor
750 Watt Direct Drive Motor
DD Control Box for 1500 Watt Motor
DD Control Box 750 Watt Motor
Remote Control

Repairs for Others:

DD Control
DD Control Low Power (P/N: 110547)

Other Useful Information:

Fault/Error/Service Codes
Breezair Direct Drive Diagnostic Procedures
Cleaning Remote Control Battery Terminals
Video of a buzzing Breezair 550W Motor (internal short circuit)


I'm writing about my personal experience, having owned a Breezair EXH-130 that had numerous problems.

This page contains a lot of technical information relating to the EXH series coolers, but also applies to the EZH, and to a slightly lesser extent, the EXQ, EZQ and EXS model range.  The information here should help you if you're looking to troubleshoot your cooler.  While the information is technical in nature, efforts have been made to make it fairly easy to understand.

My original Breezair unit, an EXH-130, had a troubling history of failures and this was the motivation for publishing the information here.  I'm not the only person that's having trouble with these coolers.

Unfortunately, the newer EXQ series of coolers probably aren't going to be much better.  I've already had some faulty control modules from those coolers come in for repair, and can tell you that they haven't changed much.  They've added some token surge protection to the motor drive circuitry and changed the communication circuitry to accommodate their new MagIQtouch controller, but that's about all.  The rest of the circuitry within the control module appears almost identical to the earlier EXH/EZH control modules.

Another caveat, is that replacement parts for these coolers are generally expensive.  A new motor or control module is going to set you back around $600.00 or a little more.  The drain valve assembly costs around $300.00, a new pump is usually around $130.00, and a new wireless remote, around $350.00.  These prices don't include installation.

As of late 2017, the cooler that this blog page focuses on is no longer with us.  Most of the parts found new homes, and the rest went out in this year's hard rubbish.  It has been replaced with a newer Breezair EXH-210, but thats already needed a new drain valve and water inlet solenoid valve.

During the time I owned the EXH-130, I had to conduct a number of repairs:
  • Repair 1: The motor wouldn't run.  When turned on it would just buzz/groan and wouldn't move.  The motor had developed a short circuit in the windings.
  • Repair 2: The water pump stopped running.  A little percussive maintenance got it going again, but its probably going to die more permanently soon.
  • Repair 3: The cooler started tripping the circuit breaker randomly.  It would work fine for a few days and then all of a sudden the circuit breaker trips.  Resetting the circuit breaker a couple times usually "fixed" it for a few days, then it'd do it again.
  • Repair 4: The motor developed another short circuit and damaged the motor controller IC as well.  The controller IC needed to be replaced, which I've done.  I also managed to get hold of another similar blown up motor (from an EXH-150) and repaired that.  If I wasn't repairing the faults myself, a new motor and new controller would cost around $1200.00 + installation.
  • Repair 5: The drain valve couldn't make up its mind if it wanted to be open or closed (it would repeatedly open and close again).  This is a known issue and replacing the two microswitches inside the drain valve assembly sometimes cures this issue.  In my case, that was not the problem.  The synchronous motor inside the drain valve was the problem.
All of this occurred within 13 months.

In case anyone is interested in knowing more about the faults described above, I'll go over some of the details in a moment.  It would be nice to purchase a new motor and other parts, but the prices of the parts are prohibitive.

Due to these prices and my background in electronics, I've been repairing all of the faults myself.  I also do repairs for others.  You will find my business and contact details below:

Repair Details:

Repair 1: The Motor

The motor used in the direct drive coolers (EXD, EZD, EXH, EZH, EXQ) is a brushless DC motor (BLDC).  The motors are electrically similar to a 3-phase motor, internally wired in a "star" configuration.

The motor had developed what I'll call a "phase-to-phase" short, meaning that there was a short circuit between 2 of the 3 windings in the motor.  Upon opening the motor for the first time, the first thing I was concerned about was the way in which it had been designed.  There are 3 windings in the motor, each winding consists of 20 electromagnet windings in series.  The 3 windings are all offset slightly from each other, and are all wound on top of each other.

There is no insulation, other than the very thin enamel coating on the magnet wire inside the motor to prevent a phase-to-phase short.  In addition to this, I've read various documents from electric motor manufacturers that clearly state that this style of motor should not be used in humid or dusty environments.  Further more, the motor in the cooler is not sealed, and as such, the windings are exposed to both humidity and dust.

I think these motors would be much more reliable if they just had a layer of insulation between the 3 windings.  It'd be even better if the coils weren't wound on top of each other.  The short circuits generally develop close to where the power enters and exits the motor, and this is also where the voltage differential between the windings is at its greatest.  The design of the motor means that the enamel on the wire within the motor needs to be able to withstand a voltage differential of approximately 430V DC.  That isn't a big ask, but it also needs to withstand having dust collecting on the enamel and being exposed to moisture/humidity.

Initially, I was a little unsure about how to go about repairing this motor.  The obvious answer was to re-wind the entire motor, but I could see that'd be a lot of work.  The other option was to locate the fault and either isolate it or render it harmless.  I chose the latter.

To do this, I used a multimeter to determine which two phases had shorted.  The next thing I did was break the internal connection inside the motor where all 3 windings are bonded (connected) together.

After doing that, I took a 12V power supply and a 50W halogen downlight and connected it up in series with the shorted turns of the motor.  The idea of the lamp was to limit the current passing through the motor windings.  Without the downlight or some other current-limiting device in series with the motor, a lot of current would have been drawn and this could have caused further damage to the motor windings as they would have gotten quite hot.

I ran the light in series with the shorted motor windings for a little while and the windings on the motor started heating up.  I then used a laser non-contact thermometer to find where the motor windings were hottest.  This seemed to roughly point to the spot where the short was.

In an attempt to further verify the location of the short, I used a small fridge magnet (thin, rectangular shape) and moved it over the motor windings while still running power through them via the downlight.  This allowed me to feel where the magnetic pull of the motor was strongest and also seemed to help confirm the rough location of the short circuit.

The next bit gets tricky, and I don't know of a good method of doing it.  As I said earlier, the motor is a 3-phase style motor, and each phase consists of 20 electromagnet windings in series.  My plan was to isolate the fault and bypass it.  I figured that if I lose about 1 electromagnet out of 20, it probably wouldn't matter much.  After determining how the motor was wound and which direction the current was travelling around the motor, I randomly cut one wire in two electromagnets in the same phase winding (read that a few times, it should make sense.  In total, I made 2 cuts).  This allowed me to bridge over the fault, meaning that I've probably lost about 1 electromagnet from the second phase.  The short is still there, but it's semi-isolated and sort of harmless.

This got the motor going again, and it worked for about 10 months, until the motor developed another short.

Below are some photos of the motor internals.  As you can see, the 3 sets of windings are all wound on top of each other, with nothing but the enamel on the wire preventing short circuits.  These motors would probably be much more reliable if an additional layer of insulation was placed between each phase.  The phase-to-phase shorts that this motor has developed all seem to develop at the top or bottom of the motor windings, not on the side.  They also tend to develop where the motor collects dust in the windings.

Here is a picture of the top of the motor.  The small PCB contains the following:
  • 3 Hall Effect Sensors.  These are used by the motor control circuitry to determine the current position of the motor.  This information is then used to determine which coils (phases) to turn on next, in order to make the motor move.
  • A voltage divider network.  This is used to set a unique voltage level on one of the pins in the sensor cable.  This signal can then be analysed by the motor control circuity to determine the wattage of the motor connected to it.
  • Two connection points for an external thermostat switch located to the right of the PCB.  The switch is used to shut down the motor if it overheats.
In the picture below, you can see the PCB I've described above, as well as the way the 3 phases are wound on top of each other:

The side of the motor.  Each electromagnet is 3 notches wide, and each phase is offset by 1 notch:

Repair 2: The Water Pump

One day, for no apparent reason, the water pump stopped running.  I gave the pump a "smack" and it was off and running again.  The pump became quite noisy, but lasted until the cooler was de-commissioned.

Repair 3: Tripping Circuit Breaker

Initially it was just a weird event, I reset the circuit breaker and everything seemed fine.  A week or so later, it did it again, so I reset the breaker again.  Over time, it started getting worse, randomly tripping the breaker every 2-3 days.

I pulled the control box out of the cooler and examined it.  I couldn't see any problems, and couldn't find any faults.  I re-assembled the unit and put it back into service.

Predictably, it did it again.  This time the fault remained after the circuit breaker tripped.  Usually, after the breaker tripped, I'd measure the resistance between the active and neutral pins of the power lead plug and the reading would be acceptable - around 400 ohms.  This time, though, I measured just a few ohms.  I initially suspected that one of the filter capacitors across the mains has failed short-circuit, but after desoldering those, the short was still there.

I then decided to begin isolating sections of the controller circuitry by removing various common-mode chokes (pictured below).  These components basically filter noise and help reduce interference.  It turned out that the first choke I removed was the culprit.  I suspect that the windings on the choke may have been vibrating slightly and had worn through the insulation on the toroidal core.  This caused a short circuit inside the controller, hence tripping the circuit breaker.

I found a second-hand choke among my scavenged components and re-constructed the below component, then replaced the below component with my newly made one.  The circuit breaker hasn't tripped since.

Here is a picture of the faulty part.  If you look closely you can see where it failed.  On the left, it failed about 4 turns down from the top.  On the right, it failed about 7 turns from the top:

This type of failure has turned out to be a fairly common fault.

Repair 4: Another Motor Fault

It's this fault that gave me the motivation to write about the problems with my evaporative cooler in the first place.  The motor developed another inter-phase short circuit, close to where the power enters and exits the motor windings.

I used a different method to find the fault this time.  Instead of running power through the motor and using the non-contact thermometer or a magnet to help locate the approximate location of the fault, I used pressure.  The fault this time was intermittent, the motor would buzz/groan, wouldn't move, but when I tested the resistance of the internal windings with a multimeter (before removing the motor from the cooler), it measured about 20 ohms between any two pins on the motor power connector.  So, I re-connected it, powered it up again... buzz/groan.  Measured it again, this time I had 1.8 ohms between two of the phases.  This confirmed a short in the motor.

I took note of which two pins had the 1.8 ohm resistance and then proceeded to remove the motor.

Once I'd disassembled the motor, I figured out which pins on the motor power connector were connected to which windings.  Once I'd figured that out, I knew which two phases were shorted.

At some point during the diagnosis, the short just disappeared.  In an effort to find it again, I started applying moderate pressure to the coils and eventually located a spot where I could apply pressure and I'd get a short circuit.  So, I knew roughly where the fault was and went about isolating it using the same method as last time, which is basically just cut some random wires and hope for the best.  It seemed to work and I was able to (after a lot of testing & re-confirming my findings) figure out where to isolate the failed winding.

Pictures of the motor on my work bench:

With the fault isolated, I re-tested the motor resistance at the power connector and it seemed to be normal, around 20 ohms.  So I re-assembled the motor and put it back in the cooler.  Buzz, groan.. Urrrggghhh.

I removed the motor again and using the pressure technique, found another inter-phase short.  Then, while messing with the motor again, the short disappeared.  I'd pinpointed where it seemed to be but all of a sudden I couldn't use pressure to make the short re-appear.

Applying pressure to the windings (pinching them):

So, since the short circuit just "fixed itself", I re-assembled the motor and put it back in the cooler (in a very temporary manner), and powered it back up.  Buzz, groan.  I figured that would happen.  So that re-confirmed that there was still a problem.

Further investigation of the motor windings under a magnifying glass and in good light revealed a small section of windings where the enamel had been burnt.  Applying some light pressure to that burnt area resulted in the short circuit coming back.

Here is a photo taken through a small magnifying glass of the burnt area.  That blue mark was supposed to be an arrow pointing to the burnt section:

I've isolated the above short by bridging across the coil on the outer phase rather than isolating the burnt section (which is in the centre phase).  The reason I did that was because I'd already lost a coil from the centre phase in a previous repair, so I chose to even it up a little by isolating the outer coil.

After re-assembling the motor and putting it back into the cooler, it just buzzed.   It wasn't as loud as before and with a bit of encouragement the motor started running but would occasionally jolt or make clunking noises and then go back to normal.

I contacted Breezair/Seeley International to see if they'd be willing to test the control module.  I ended up getting a call from the "Victorian/Tasmanian State Service Manager", but he basically just said that the components of the cooler aren't designed to be repaired and that they have field service technicians that can come out and test the parts to determine the fault.

Since they weren't much help, I continued troubleshooting.  The power to run the motor goes through an IRAMS10UP60B hybrid module.  This module has a high voltage side and a low voltage control interface which also contains some additional smarts.  Due to the motor having had short circuits in the windings, I figured it'd be possible that this module may have been damaged due to that, so I ordered some and replaced it.

This cured the problem.  The hybrid module contains 6 IGBT's.  They're like switches that can turn on and off very quickly.  One of the known failure modes for an IGBT is "latch-up", which means that the IGBT can turn on but can't be turned off reliably, or at all.  My suspicion is that the last motor short caused damage to at least one of the IGBT's, and this in turn caused incorrect commutation of the motor.

Repair 5: Drain Valve

The drain valve developed a fault whereby it would repeatedly open and close.

I bench-tested the drain valve with a 24V AC power supply and re-produced the constant open/closing problem that it had.  I double-checked the microswitches inside the drain valve assembly and they were working fine.  They had been replaced previously, since I was hoping for a quick fix.

The motor inside the drain valve turned out to be the problem.  It's a synchronous motor which has the ability to run clockwise or counter-clockwise at its own will.  The problem seemed to be that, on occasion, the bushing around the shaft that comes out of the motor would catch and seize up, causing the motor to reverse direction.  Hence the constant opening and closing of the valve.

After further investigation, it turned out that the output shaft of the motor and the bushing around the shaft had seized, as the bushing was rotating.  The bushing isn't supposed to rotate with the shaft and would occasionally catch and seize up.  This in turn caused the drain valve to continuously open and close as when the motor seized up, it would reverse direction.

I replaced the motor with a brand new one and the drain valve now works again.  I also re-installed the original microswitches, since they were still functional and were of better quality than my substitutes.

If you are interested in seeing the guts of the synchronous motor, I pulled apart the faulty one and took pictures throughout the process.  Here's the link:

SUH DER SD83-A Synchronous Motor Teardown

My first temporary fix (this unit isn't on the roof, so I can drain the water manually):

That's one of the pad frame clips jammed into the drain valve to keep it closed.  At this point I will mention that this is overall a bad idea.  Salt and other minerals will build up in the water as time goes on, and this will cause white deposits on your cooling pads, shortening their life expectancy.  At some point, the cooler will want to drain the water and it'll be unable to.  This will cause fault code 4 to be reported.  If you're stuck and want the cooler running, you should be able to loosen the base of the drain valve so that it leaks slightly.  This will help keep the water fresh.

After getting sick of opening up the cooler each time I wanted to drain the water, I decided that putting a tap on the drain pipe would be a better solution.  I got the tap and PVC pipe from a hardware store, in the garden section:

The problem with this solution is that it drains rather slowly in comparison to how it would without the tap interfering with the water flow.  Generally, I can't be bothered waiting for the tank to drain through that tap, so I just unscrew the whole assembly at the base of the cooler and let the water flow out rapidly.

The above has been a summary of all of the repairs my first Breezair cooler needed.

Other Breezair-related Repairs:

I'm often repairing evaporative cooler and heater control boards of all brands.  In addition to that, I'm often given faulty items or buy them from people who don't want them.

Below is an incomplete list of predominantly faulty Breezair components I've purchased or been given:
  • 550 Watt Direct Drive Motor (P/N: 822396)
  • 750 Watt Direct Drive Motor (P/N: 822426)
  • 1500 Watt Direct Drive Motor (P/N: 822440)
  • DD Control Box - High Power (P/N: 110554)
  • DD Control Box - Low Power (P/N: 110547)
  • DD Control Box - Low Power (P/N: 110066)
  • DD CPMD (P/N: 108988)
  • Motor Control DD (P/N: 109138)
  • Sensortouch Remote Control 1
  • Sensortouch Remote Control 2

Most of these parts were purchased knowing they were faulty, others were donated.
Repair Details:

550 Watt Direct Drive Motor:

This motor was repaired exactly the same way as documented above.  The motor had an inter-phase short.  The shorted section of the motor was isolated and bypassed.  After the repair, the motor was put back into service and worked for approximately 3 months.  It failed again just after the summer of 2013-2014.

Because this motor is now basically junk, I decided to experiment with it.

Firstly, I did something fairly insane and against my better judgement.  I pressure washed the motor stator (the windings) with normal tap water and a pressure washer.  That got it nice and clean.  The motor was then left to dry a little, wrapped in a towel.  It was a hot and windy day and I didn't want debris getting into the nice clean motor, hence the towel.

I then finished drying out the motor by connecting the 3 phases in parallel and running 12V AC through the windings from a heavy duty transformer (12V AC @ 13 Amps).  This heated the motor windings up to about 65c.  It was left to dry like this overnight.

Experimenting further, I purchased the necessary items to build a small vacuum chamber.  It basically consists of a high-vacuum pump, a 50 litre stockpot, a 20mm thick piece of perspex (the lid) and some internal bracing rings to strengthen the pot and prevent it from imploding when under vacuum.  The lid is sealed to the pot by a rubber gasket made of 3mm thick rubber sheet.  The vacuum in the chamber holds the lid on and forms an excellent seal.

What I'm doing here is partially "potting" the motor windings, using an epoxy-based compound designed for this purpose.  It has very high dielectric strength (it's a good insulating material) and it provides good thermal conductivity, which helps with heat dissipation.  It's also somewhat flame retardant.  Once cured, it becomes rigid and will prevent movement in the windings.  It will also prevent moisture and dust from coming into contact with the motor windings in the potted area.

The motor windings are potted under vacuum, hence the need for a small vacuum chamber.  The idea is to displace any air trapped in the windings and draw the potting compound deep into the windings.

What I'm hoping to achieve by potting the motor in this way is a reduction in the failure rate.  This motor has already failed twice, so under normal circumstances, it should fail again very soon.  By potting the part of the motor where the shorts tend to occur, I'm hoping that any vibration in the motor windings will be eliminated and that dust and moisture will be kept out and the repair to the motor will last longer.

Unfortunately, this is pretty much a one-way process.  There's no way that I know of to remove the cured potting compound without damaging the motor windings.  If the motor does fail again, it's basically junk at that point.

Due to the experimental nature of this, I also took the opportunity to embed a K-type thermocouple into one of the potted sections of the motor windings.  I did this so that I could measure how hot the potted part of the motor was getting during operation, but I needn't have bothered, as it doesn't get hot at all.

Since doing the initial potting of this motor, I have improved the vacuum chamber by adding four banana jacks to the lid, which will allow me to feed power into the chamber and also give me the ability to monitor the temperature of the motor windings while doing so.

The idea is to feed power to the motor while it's under vacuum and being potted so that I can speed up the potting process by heating the motor windings and in turn the potting compound.  I've also purchased a digital thermostat that can take a K-type thermocouple input to turn a relay on/off at a set temperature.  My plan is to use this to keep the motor windings at a pre-set temperature while they are undergoing the potting process.

This motor hasn't failed yet, but it's not being used in a cooler either.  I currently use it to test control modules.  The motor was potted on 05/01/2015.

Update on the 550W motor and the vacuum chamber:

The 550W motor is still working and hasn't failed again to date (20/12/2021).  The motor gets run at maximum speed for long durations while testing control modules that have been repaired.

750 Watt Direct Drive Motor:

This motor failed the same way as the others, and was on its way to developing its next failure.  You could technically say this motor has failed in two locations.  The first location I found and repaired.  I then tested the motor and discovered seemingly random incorrect commutation.

I had my doubts about the controller I was testing the motor with, so I swapped it for another known-good one.  The problem persisted, and upon further examination of the motor, I found a second area where the enamel wire had been burnt.

This motor has been repaired and potted also.  Unfortunately I don't recall what happened to this motor, but I know that it didn't fail while it was in my possession.  I most likely sold it to someone who was desperate for a motor.

Vacuum Chamber:

The vacuum chamber was improved as mentioned above and this motor was the first one to be potted in the improved chamber.  Photos of the vacuum chamber as well as some explanations of the equipment in the photos are below:

Above: Improved vacuum chamber, initially you couldn't see inside and there was only a port on top for the vacuum hose (brown hose seen above).  4 banana jacks were added to the aluminium plate, two are used for sensing the temperature of the motor windings while the potting process is being completed (red and black).  The two white jacks are used to bring 24V AC into the vacuum chamber to heat the motor while potting.

The black box on top is a programmable temperature controlled relay.  It is pre-set to keep the motor at 80C and also shows the current temperature.  Heating the potting compound initially reduces the viscosity of the potting compound, which helps it get into all the small gaps in the windings, as does the vacuum itself, in theory.  The other advantage is that potting a motor only takes a couple of hours as opposed to doing it at room temperature, which takes about 8 hours.  The next improvement would be to add a vacuum sensor and automatically run the vacuum pump as required, as there is a very small vacuum leak somewhere.

There are two wooden rings in the chamber, one below the motor stator (the white plastic part) and one above it.  They are there to help prevent an implosion of the vacuum chamber.  There's a piece of extruded aluminium rod in the centre, you can clearly see the pattern of the extrusion where the lid is being pushed down by the ambient air pressure due to the vacuum inside.

Due to the implosion risk, the potting process is a largely unsupervised process.

Above: Left to right - ignoring the frame of the hydraulic press, we have a box with a transformer in it which is a 24V AC transformer with a maximum output current around 10A.  There's some kitchen scales there for mixing the potting compound up (it's a 2-part epoxy resin that needs to be mixed by weight).  The vacuum chamber in the centre, and the vacuum pump on the right.  The vacuum pump needed a new motor and I happened to have a ~500W motor laying around from an old Breezair belt-drive evaporative cooler, so I used that.  The vacuum pump is very old but also made in Australia and still going strong.

Above: Photo of a potted motor.  The top part has been potted first, then the bottom part.  You can see the mould I made for the potting process, which is what the motor is sitting in.  Not much likes to stick to polyethylene plastic, which is what the mould is made of.  That said, if it does stick, the plastic can be broken away from the base to free it, as it's only held there by superglue.

Above: The finished product.

DD Control Box for 1500W Motor:

This control module needs a new IRAMS10UP60B hybrid module, since it has failed rather explosively.  Most of the time when this happens, the high voltage used to run the fan motor (~420V-430V DC) finds its way into the 15V and 5V control circuitry, as there is no isolation between the high and low voltage circuitry other than the insulated gate property of the IGBT's inside the IRAMS10UP60B hybrid module.

Here is a picture of two of the hybrid modules.  The top one has failed explosively.  The one below it is physically in-tact, but internally has one or more failed IGBT's:

DD Control Box 750 Watt Motor:

This one might scare you.  To be honest, it worries me.

It's another case of a common-mode choke failing.  The failure is similar to the one documented above, which occurred in my cooler.  Fortunately for me, mine didn't catch fire, but this one did!

I've repaired this board by using the choke from another board that was damaged beyond reasonable repair.  The common-mode choke failed, causing a short circuit from mains active to neutral, via the toroidal core.  The short circuit/arcing caused the plastic cable tie to get hot and catch fire, dripping flaming plastic drops onto the components and parts of the controller casing below.

The collateral damage was the two wires that go to the circuit breaker and the mains power socket.  I decided to replace the damaged wires with ones from a parts controller.  The power socket wasn't damaged enough to warrant replacing it.

Here are a few pictures from the insides of the controller.  First up, the choke that caught fire:

Burnt spots inside the controller casing.  This appears to be where flaming drops of melted plastic from the cable tie around the base of the choke have dripped down onto the bottom of the plastic casing:

The image below shows cosmetic damage to a capacitor close to the common-mode choke that caught fire.  It also shows damage to the two brown cables that go to the circuit breaker, as well as minor damage to the mains power connector (the pitting around the edge is not supposed to be there):

The scary thing is that this failure could happen at any time.  The common-mode choke that failed in this case is continuously powered by the mains.  It doesn't matter if your cooler is turned on or off at the wall control/remote.

Here is a close-up of the damaged area:

In the picture below, which is otherwise the same as above, I've highlighted where the copper turns of the common-mode choke have melted away and gone open-circuit:

Remote Control:

I recently purchased a faulty Breezair Sensortouch remote control.  It was advertised as "New" and the description said that it would freeze after the first command.

I purchased it not being sure what its problem would be, but I had my suspicions.  I was hopeful that it wasn't a fault in the microcontroller inside the remote control, since I couldn't replace that if it was damaged.

There was no evidence of battery electrolyte leaking onto the circuit board, however, one of the pads for the buttons on the front of the remote was measuring low resistance (about 100 ohms) while all the others were measuring about 700K.

As there was no evidence of any sort of contamination on the circuit board, I traced what the pad was connected to.  One side of the pad was connected to battery negative, while the other side of the pad was connected to a HEF4021 IC and another component in a SOT-457 package labelled as "B2" (which I suspect is an NXP PMEM4010PD).

Since I had the HEF4021 chips in stock and they're easy enough to replace, I did that, suspecting that the chip had possibly been damaged by static discharge or something like that.  It made no difference.

Not having the "B2" part in stock, I de-soldered it and then re-checked the resistance across the pad.  It changed, but not much, so there was still a short somewhere, and the only place left was the pad itself.

Here is a close-up of a couple of pads.  They are gold-plated contacts, in a fork configuration:

Somehow, one of the pads had become conductive and this was telling the remote control that someone was pressing and holding the economy button.

I cleaned the circuit board with PCB cleaner multiple times and it didn't fix it.  Since the obvious failed, I decided to use a clothes pin to dig shallow trenches in the gaps between the gold fingers on the pad in question.  This resulted in the resistance of the pad increasing substantially and cured the problem.  The remote control is now fully functional.

As a precaution, I also cleaned the button membrane with dishwashing detergent and an old toothbrush, washed it off and then thoroughly dried it.  For completeness, here is what the back of the button membrane looks like.  When you press the buttons on the remote, the conductive pads make contact with the gold fingers and this lowers the resistance of the pad.  This in turn is detected by the remote as someone pressing a button:

Repairs for Others - DD Control (P/N: 110066):

I was contacted by someone who had a faulty control module.  He provided me some high-resolution pictures of the visibly burnt parts of the unit and I basically did a remote diagnosis of the problem from the photos I'd been provided.  Obviously, I couldn't check everything or poke around at all the components I wanted/needed to.  He was in Perth and I'm in Melbourne.

The person in question ended up sending me his control module.  My plan was to take a look at it, do a proper diagnosis and attempt a repair.  If the repair failed I was prepared to cover the cost, even though I didn't really want to.  I figured that if the repair failed and the controller went up in smoke when I tested it, then really, I'd failed in my attempt to repair the unit and the customer shouldn't be expected to pay for that.

So I did the diagnosis, ordered parts, waited in excess of a week for them to arrive, kept the customer informed throughout and eventually did the repair.   Unfortunately, I was hit by a power company screw-up at this time and I wasn't able to test the repairs to my own satisfaction.  I ran his repaired control module from a pure sine wave inverter for 5 minutes to test it.  Normally, I'd have run it for much longer, an hour or more.

I've since found out that the repaired controller is working well.  I'm happy that I've managed to save someone $700 or more.

DD Control Low Power (P/N: 110547):

This control module suffered a failure in the Power Factor Correction part of the board.  There was evidence of arcing across the PCB beneath the MOSFET, however there was no trace of what caused it.

The MOSFET still tested OK, but was replaced as a precaution.  Ceramic capacitor C151 was replaced as it had been permanently discoloured on one side by the arcing.  The two surface mount transistors were also replaced, mostly as a precautionary measure but motivated by the fact that I couldn't test one of them in-circuit.

Below is a picture of some of the damage.  To the left you can see R102 and R103.  In the centre is the location of the MOSFET and you can see something nasty has happened.  I suspect that the arcing (tracking as it's known) occurred due to the PCB having become contaminated, or maybe it was just a spider in the wrong spot at the wrong time.  Death by spider seems to be a fairly common occurrence in these control modules.

Other Useful Information:

Fault/Error/Service Codes (for 110547, 110554, 112954 models):

Below is a list of the fault codes and briefly what they mean:

Fault Code 1: Communications problem - check communication cable between wall control and cooler for damage.

Fault Code 2: Water not detected at salinity probes (usually within 8 minutes) - water turned off, solenoid valve faulty, no power to solenoid valve (should be around 24V AC at solenoid valve terminals when cooler is in cool mode) or faulty (open-circuit) salinity probes.

If you receive fault code 2 within 10-15 seconds of turning the cooler on, then you likely have an EEPROM corruption problem (see fault code 3).

Fault Code 3: EEPROM Failure or Corruption.  The control board stores a small amount of data related to settings for the operation of the cooler in an EEPROM chip.  If this data becomes corrupt, you will often receive fault code 3.  This fault code isn't documented but it is repairable by replacing and/or re-programming the EEPROM.

Fault Code 4: The cooler wanted to drain the water from the "tank" at the bottom of the cooler but after waiting 4 minutes, water was still detected by the salinity probes.  This suggests either a faulty drain valve (not opening) or a blockage in the drain pipe.

Fault Codes 5 & 6 aren't documented and I'm not sure if they're even possible.  If you have either of these fault codes then please get in contact with me.

Fault Code 7: Mains power supply frequency is incorrect.  In Australia, we have a nominal 50Hz power supply frequency.  Fault code 7 will be produced if the mains frequency is outside the limits of 46-54Hz.  This can be caused by contamination to the circuit board in the control module (eg. spiders and other insects), generators, loose/bad connection at the power entry IEC connector or other internal faults (eg. dry/cracked solder joints or electronic component failure).

Fault Code 8: A brief power failure has been detected.  Nothing to worry about in general.

Breezair Direct Drive Diagnostic Procedures:

I've written a document detailing some procedures that can be used to diagnose your Breezair evaporative cooler.  This document applies to direct drive models only, such as the EXH/EZH/EXQ/EZQ series.

The document includes sections to aid in the diagnosis of faults relating to each component of the evaporative cooler.  A multimeter is recommended, but not generally required.

You can download the document from the following link:

Cleaning Remote Control Battery Terminals:

I've just had to clean the battery terminals of my original remote control.  One of them in particular had turned completely green.  This was caused by leaking alkaline batteries.

Normally I'd take a rotary tool and carefully grind it off and make the terminals look pretty again. 

This time I tried vinegar.  It may have worked a little, but it wasn't good enough.

Next, I thought I'd try a different acid.  I got a small amount of Ranex Rust Buster (phosphoric acid) and drowned the terminal in that.  It immediately started fizzing and ate away the corrosion.  The contact it left behind (on the left) is pictured below:

While I was soaking the terminal in Ranex, I started wondering if the Ranex would do any harm to the plastic case of the remote.  So I put some on a cotton bud and rubbed it on the plastic where the old batteries had left a rust stain.  It cleaned up well.  Here are the before and after photos:



Video of a buzzing Breezair 550W Motor

Below is a video of a Breezair 550W Direct Drive motor with an inter-phase (or phase-to-phase) short circuit.  It's the common type of short circuit that the older green coloured direct drive motors tend to develop.

This motor has since been repaired (for the second time) and seems to be running fine again.  Running the motor, knowing its got a short circuit in it is a risky thing to do as it could damage the control module, but I did it anyway for the sake of making the video and potentially helping someone diagnose their cooler in the future.

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