Wife is house-sitting her Mom's place in north Toronto, while her Mom is away for a 6 week vacation in Africa.
Her mom runs the AC too cold for my wife so I re-programmed the thermostat to be 75 degrees from its original 72 degree setting.
Next day the house is unbearably warm - 86 degrees inside according to the thermostat. I triple check the thermostat, do a hard reset, re-program and also try temperature over-ride. The thermostat indicates that it is cooling. It turns on the blower fan and the outdoor AC unit.
The supply plenum above the cooling coil is room temperature, as is the cooling pipe from the outdoor AC unit to the coil. The fan on the outdoor unit runs, but blows cool air out the top, not warm air like it should while removing heat from the house.
To me that indicates a total loss of coolant, but that seems highly unlikely given that only hours earlier, the AC produced air that was ice cold. Would have to be a sudden catastrophic failure, but there is no sign of any recent leak/damage that I can see in the lines from the external unit to the coil in the supply plenum.
Something doesn't seem to add up here. Seems to be too much of a co-incidence that the cooling fails suddenly after I adjust the thermostat a couple degrees.
Am I missing something obvious here?
Getting the unit serviced may take several days, as we first have to make contact with her Mom to authorise any work/repairs.
Unfortunately, my wife is living at the house full time, and it's too hot for her to sleep! She can't come home, since our house has been gutted and is undergoing a major rennovation right now.
Furnace - Lennox Complete heat combination gas water heater/furnace
Outside AC unit - Lennox (don't have a model number)
Thermostat - Lux500
All HVAC is original equipment from when the house was built about 5 years ago.