Aircon trips out and RUN light blinks in cooling mode


  #1  
Old 12-31-18, 10:59 PM
J
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Aircon trips out and RUN light blinks in cooling mode

I have a large ducted air conditioning system about 16 years old - the compressor is rated a 7Kw at 415 volts.
Lately on hotter days when the temperature outside is 34C or more (93F +) especially in late afternoon when the sun is shining directly on the end of the outside compressor unit where the controller electrical circuit and compressor are located) the aircon turns off and the RUN light on the control panel inside blinks. After about 20 minutes or so it restarts and the RUN light remain on (not blinking).
The filter inside the house for the return air is clean.
Any ideas?
Also I have noticed that one of the two cooling fans on top of the outside unit appears to spin slower than the other one at I have even seen it slow down for probably no more than 100 rpm. What could cause that? Faulty run capacitor or faulty fan motor?
Thanks
 
  #2  
Old 01-01-19, 12:16 AM
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Welcome to the forums from down under.

Our systems are set up a little differently than yours. It appears you have a large packaged unit.
It sounds like your unit is overheating and shutting down on thermal overload. A condenser fan not running properly is one reason for over heating. It could be a motor or cap. Typically the cap is a small price and is the best place to start.
 
  #3  
Old 01-01-19, 12:57 AM
J
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Thanks for that advice.
I also was wondering if it could be caused by a high pressure switch or low pressure switch tripping out. The aircon on a car I owned some years ago started to trip out all the time and I traced that to a high pressure switch tripped out because there was a partial blockage in the gas line causing a pressure build up but my house aircon only trips out when the outside air temperature gets hot and so shouldn't be caused by a partial blockage.
What happens if the gas level is a bit lower that it should be?
Also can a run capacitor change its capacitance causing the motor to slow down when getting hot or do they either work or not work? Surely if they stop working then the motor won't run?
 
 

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