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Mistral Evaporative Air Con Repair (With Video)

By on April 6, 2019
how to repair Mistral air con











Here in Australia, it gets hot – very hot. But what most people don’t realise is that it also gets very cold. Where I live in New South Wales at an elevation of 702M, the temperatures range from 40°C in the summer, to a chilly -10°C in the winter.

So to say that we need both good heating and cooling is an understatement.

In my little automotive workshop, I use 2 cooling fans. Firstly a small industrial fan that sits on the ground and also an evaporative air conditioner and heater that I picked up off the side of the road – someone else’s cast off.

how to repair mistral air con


On this particular day, the mercury was heading toward the 40°mark and you guessed it – that was when my trusty curb-side-find finally gave up.

Most of the features worked – it had power, the fan worked, the heater worked (not that I needed it at this point), but the main complaint was that the recirculating mat that moves the water from the base of the unit, past the fan to provide cooling, would not operate.

mistral air con fix

Disaster had struck! Repair of this unit became a priority so that I could have cooling back in the workshop again!

The electric motor that drives the rotating mat refused to work. After checking for voltage, the LED indicated that a section of the circuit was working, but the motor was not being supplied the necessary voltage.

synchronous motor

After tracing the wiring back to the control circuit board, I could see that a series of triacs (VA 0607 V89S) were used to control the switching of the features. Although some strange readings were seen on-board, after removal from the board, the triacs tested fine. Nearby resistors also were tested and were within parameters.

triacs (VA 0607 V89S)

The main issue was with the triac listed as ‘cool’, so after focusing on the testing it off-board, it was time to test it again, this time on-board.

testing triacs

It seems that dry solder joints were the issue, since the flow operated correctly as soon as I soldered the triacs back on the board.

checking voltage using digital multimeter

Just to confirm the repair, I measured the voltage and switching of the triacs. They all operated correctly and after assembly of the cooler and mat assembly with lubrication of the rolling mechanism, I let the appliance operate for 2 hours before calling it a fix.

Everyone one was happy with the result and cool was restored to the workshop.

If you are interested in this repair, you can see a video on my channel following the link below:

This article was prepared for you by Mark Rabone from Australia.

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Note: You can check out his previous repair article below:




  1. Robert Calk Jr.

    April 6, 2019 at 1:03 pm

    Good job, Mark.

  2. Yogesh Panchal

    April 6, 2019 at 2:52 pm

    Mark, Good JOB!

    • Mark

      April 6, 2019 at 9:00 pm

      Thanks Yogesh

  3. Albert van Bemmelen

    April 6, 2019 at 3:08 pm

    The temperature range from 40°C in the summer, to a chilly -10°C in wintertime begins to sound much like the extreme weather in my country Mark. Last summer we had about at least 7 weeks with very hot days around 30 to 35 degrees Celsius and not a drop of rain in all of that time! Which was an abnormal event that lowered the ground water levels to the even today still dangerously low levels on higher grounds.

    • Mark

      April 6, 2019 at 8:59 pm

      Hey Albert,
      Just to make matters worse, 2 weeks ago we had flash flooding at the college I teach at. I had to stop classes as water came into the workshop up to our ankles and started coming into the classroom. For the afternoon the students helped by trying to sweep water out of the workshop.
      When I lived in South Australia, we had a recorded drought called the 'Millennium drought' which was between 2001 and 2009. One extreme to the other! The Murray River dried up so much that houseboats could not travel on the river as they would get stuck and 4 cars fell into the river when the bank collapsed. Strange Weather!!!

  4. Mark

    April 6, 2019 at 3:51 pm

    Thanks Robert 🙂

  5. Parasuraman Subramanian

    April 7, 2019 at 10:38 pm

    Excellent step by step troubleshooting! Thanks for sharing!

    • Mark

      April 8, 2019 at 9:33 pm

      Thanks Parasuraman

  6. Ian Corry

    April 9, 2019 at 6:13 am

    Well done Mark. Great repair article and superb Youtube video.

    • Mark

      April 10, 2019 at 9:24 am

      Thanks Ian,

      Glad you liked the video. I have quite a few electrical videos on the channel you might enjoy 🙂

  7. Aword Stephen

    April 9, 2019 at 9:16 pm

    Good work Bros but I have one for a client, it's coming on but the fan is not rotating, just don't know what else to do

    • Mark

      April 10, 2019 at 9:26 am

      Hey Aword,
      What other symptoms are there? Is there voltage at the motor? Are the triacs and accompanying resistors OK?


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