My A/C Will Not Run or Cool

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 My Air Conditioner Will Not Run or Cool Properly


 If your A/C unit is not starting up a couple of checks maybe in order:

  • If the outside air temperature is below 13 degrees C (approximately) the unit maybe locked out automatically due to a low temperature override. This protects the compressor from damage due to cold weather starts.

  • Check the A/C unit’s circuit breaker (the breaker may have tripped or been turned off)
  • Set the thermostat Cool-Off-Heat switch to Cool & the Fan Auto-On switch to Auto
  • Adjust the thermostat temperature setting below the current inside air temperature (indicated on your thermostat).
  • Check if the outside A/C condenser unit is running (the fan on top of the unit should be blowing air up and you should hear the compressor running (some compressors run very quietly)).
  • Now check to see if your furnace fan is running and blowing cool air. Give this step a bit of time to remove the existing warm air from the supply air ducts.

If you are still having a problem getting your A/C unit operational, Call Pro Service Mechanical.

We can help you with a professional diagnosis and repair.


To help mitigate the issues above we currently have a $89 Air Conditioning Spring Tune Up Special & Up to $500 Off a New Air Conditioner


Why is my Air Conditioner Not Cooling the Air in My Home

Your air conditioner isn’t cooling the house as you would expect.

  • Are there any doors or windows open?
  • Are there electrical or thermostat problems?


  • Is the outside air condensing unit cycling on/off more than normal?
  • The outside A/C condenser unit coils maybe dirty or obstructed by shrubs, weeds, fuzz, etc. The A/C coils are like the radiator in your vehicle. All those tiny fins can get plugged with debris and dirt.  They should be cleaned on a regular basis.  Caution: the coil fins are fragile and can easily be bent, reducing their efficiency.


  • Is the supply air coil condensate line draining properly and not clogged?
  • Is your furnace fan running?
  • Your furnace filter may be plugged, reducing the air flow to your cooling coil and your home. This can cause the cooling coil in the supply air duct to freeze up blocking air flow.
    • Check the filter and replace if needed

dirty filter

  • The cooling coil (evaporator coil) in the supply air duct maybe blocked (restricted air flow). This may result from dust and dirt buildup on the coil fins or ice build up on the coil.

evaporator coil1

  • If you have checked all the above and your air conditioning still isn’t working you may have a low refrigerant charge or compressor problem.  In either of these cases call a professional. Caution: Removal of refrigerant requires a professional, who will recover the refrigerant to minimize any environmental impact.

Air Conditioning Technician - Refrigerant



  • If this has been happening for many cooling seasons, there is a possibility that the A/C unit wasn’t sized properly when it was first installed. Sizing of air conditioning units should be left to a professional with years of supply and installation experience.
    • Caution: Air conditioners are designed to maintain a 6 to 7 degree Celsius differential between the outdoor temperature and the interior of your home. If it is 30 degrees C outside, the inside of your home may not get below 23 degrees C. This may vary due to many conditions (i.e. sunlight, humidity, home insulation, window type, location of the condenser unit, etc.)

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