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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  1. Hello Robert,

    I'm an ex Qantas ground engineer in the field of aircraft component test equipment (1959 -74). I'm absolutely impressed with your report and attention to detail. Easy to follow.

    You've adapted some really brilliant strategies to get things working however, there's one thing I believe might help for the future.

    You mentioned interwinding shorts at the top and bottom of the windings but not at the sides. I remember similar problems from my Qantas days. Believe it or not, the shorts come from the deposition of microscopic amounts of "hard" dust in the atmosphere which accumulates on the windings.

    As you are no doubt aware, windings are in themselves small electromagnets and without a hard setting varnish to encapsulate them they actually vibrate, wearing the enamel coating from the wire and allowing turn to turn bridging to occur. Simple gravity causes the dust particles to be "shaken" from the windings at the sides.

    Aircraft components adopt highly critical technology because of the need to save every gram and cubic cm of space for lightness, This necessity does away with the luxury of inter winding insulation. In order to overcome the problem of winding movement wearing away the enamel, all electric motors, new and rewound were dipped in a conventional winding varnish but inside a vacuum oven to remove air bubbles. Once the varnish was set, nothing moved and the weight saving using this method was considerable over hundreds of motor units per aircraft. A real pain in the backside to implement. Of course, simply dipping a commercially made stator in air drying varnish would no doubt do the job, Unfortunately quality in manufacture goes on a holiday in competitive manufacturing environments.

    Horizon Control.

    Mt BreezAir RC unit packed it in after the Mallory batteries decided to leave their contents inside the controller. Time for the metho/toothbrush routine. which got it kind of working again. Probem remaining was that the controller worked but the LCD display didn't so it was like hit and miss braille to get the aircon working.

    I decided to have a look inside the RC to see what could be done. I discovered while the unit was in two halves with the batteries installed that if I twisted the half with the LCD display, some of the characters would show, allowing me to use it. So that's how it is ATM because I'm not paying $380 for a remote that has virtually zero innovative technology.

    Hope the comments have helped you and others

    Richard Crawshaw,
    Perth, WA

    1. Hello Richard,

      Thanks for your comments, that was interesting, especially the info about the "hard dust" :)

      I found that the leaking batteries damaged some resistors and made them go open-circuit (some failed after the first bunch of repairs were done as well). The electrolyte also seemed to eat PCB tracks and in my case it also ate/corroded the legs off a couple of ICs as well.

      It also managed to stuff up my keypad, which is on the other side of the board. It turned all the nice golden pads into brown/black looking pads, which then also became conductive (as if the button was permanently pressed).

      If you haven't already, maybe check the condition of the pads under the LCD. Its also fairly trivial to trace back all those tracks to the MCU (main chip) and you could then check the conductivity from the LCD pad to the IC pin it goes to.

      You could also check all (or as many as possible) of your through-hole vias, the battery electrolyte can cause them to go open-circuit and there are a number of those around the LCD (at least in my remote).


  2. Hi Robert, This a great resource for DIYer's to try and save some money repairing these Air Cons.
    I recently bought 2 S/H EXH-170's. one working, the other, not. 2nd one was cheap and a good source of spares.Going to put one on my shed.
    Fault is in the Control Box. When trying to start, a hear a relay 'click', but no motor run. No fault codes.
    Did the output module test and found a low reading. Replaced with new module...same.
    No other chard bits besides,except I have since found one of the fault LED's and associated resister damaged, but think it might only be a result of a failure, and not affect motor running...

    I too have not found any schematics, which is annoying...

    I was wondering if you had any info on the 'test points' on the board? ( 2 sets of 6 pins? )
    I at least have a working unit to do a comparison, if all else fails.
    Do you still do repairs on these? That will be my last resort...lol

  3. Hi Stephen,

    I still do repairs, but I don't provide information about how to repair these units. Basically, all the information I'm willing to share publicly which may help with repair is on the blog.

    I don't have schematics or information regarding the test points, I've developed my own procedures for troubleshooting and repair over the years.

    If you decide to send a module in for repair, you can book it online at logisense.com.au



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