This is a very common problem, whether it is an air conditioner or a heat pump. Unfortunately, many times the service technician is dispatched only to find a simple problem that the homeowner could have fixed himself.
Below is a list of possible causes. Items in blue usually require a service call. Items in red however can be addressed, even fixed by the homeowner.
Faulty thermostat
Faulty contactor
Faulty time-delay relay
faulty thermostat cable
Unit off due to an open safety device- (low pressure, low temp, high pressure, high temp...)
Faulty control module
Thermostat not set properly
Emergency or shut-off switch turned off
Blown fuse in panel box
Circuit breaker tripped or off- (sometimes a breaker will trip but it won't move)
Outdoor disconnect turned off- (some have an internal pull-out plug)
Condensate pump safety switch opened- (check pump, usually located near indoor unit)
Off on outdoor reset button
Unit "locked-out"- (reset by turning off then turning back on)
The bottom causes in red are common problems and can be addressed by the homeowner.
Here is a checklist to go through before making a service call:
Make sure there is a call from the thermostat
Make sure no Emergency switches are turned off (including the furnace switch)
Make sure the breakers for the indoor and outdoor equipment are in the "on" position- reset if necessary
Make sure the outdoor disconnect is on- some have internal fuses or circuit breakers- if you know how to check fuses you may do so
If you have a condensate pump with a safety switch, check to see if the pump is completely full of water- If so, make sure pump is plugged-in and hose isn't clogged (could be a bad pump)
If your outdoor unit has a "Reset Button" press it- if that was the problem and you have to press it a second time, there is a problem and a service call will be needed
Your unit could have a safety device locking it out. Reset it by turning system off at thermostat or breaker, wait 1 minute and turn back on. Wait up to 10 minutes to see if outdoor unit starts
Hope this helps, remember - these are just rough guidelines and not all possible situations are covered.
Hannabery HVAC is registered with the Commonwealth of Pennsylvania's Office of Attorney General: PA#8215
