Shared Knowledge
“AC Repair”
(1) Central air conditioner (ac) blowing warm air at vents. A
check of compressor unit outside of house finds fan at top of unit is not
turning but circuit breaker for compressor in main circuit panel for house is
fine.
Using electrical quick
disconnect switch right beside compressor, remove all power to compressor.
Examine compressor and find on one corner there is a removable panel. Remove.
Visual inspection finds large cylinder (capacitor), which has wires connected
to it, is bulging at the button. Fairly sure bulge indicates some sort of
failure. As capacitors store electrical charge, use insulated pliers to remove
wires (making note of color of wires connect to which terminal), then short
terminals together with screwdriver (discharge capacitor) and then remove
cylinder from compressor unit.
Have to visit 2 parts stores
to find replacement capacitor. Install new capacitor, replace corner panel on
compressor unit and using disconnect, again apply power to unit. Test and fan
runs and cold air again blowing out ac vents.
Subsequent discussions with
ac repairmen indicate that capacitor failure is fairly common.
(2) Little or no cold air
coming from air vents. Check of
compressor located outside house indicates that it is running. Go to exchanger
unit located in attic (also have another on first floor) and remove panel
allowing access to actual heat exchanger. Find that exchanger is frozen solid,
not allowing air to pass through. Suspect exchanger fins are completely blocked
with dirt and need to be cleaned, so shut down system and let ice melt. Then
check exchanger unit and find it clean!? Turns out this is a symptom of low
refrigerant in the system. Know what you are thinking. Freezing symptom of too
little refrigerant? Yes! Pressure of refrigerant in system has to be in a
fairly narrow range or refrigerant in exchanger becomes so cold that moisture
in air as it passes through exchanger will condense and freeze. Do not know of
a way home owner can add refrigerant to a system. Must call technician to do
the job. Why low refrigerant? Probably a leak in the system somewhere as system
does not use refrigerant in normal use and charge should last and last.
Technician has a device to detect leaks and should be able to determine what
must be replaced. A leak is probably not going to be cheap to repair.