8 replies to this topic

[tpwu]

Dear masters,

My Window A/C out of sudden is not blowing cold air any more and I couldn't hear the compressor running. I checked the thermostat with ohm meter and got close to 0 reading. It seems good.

I checked its capacitor (labeled 45+5uf-3+6%) and got 41.6uf and 5uf for Herm and Fan repsectively. Would 41.6uf be too low causing the problem? or something else?

Your kind help is always appreciated.

[Bobice]

Did you check the overload on the compressor ? Did you test the compressor with the ohm meter. Do this remove the cover from compressor and with meter set to Rx1 touch each terminal with one meter and the other lead to the "shell" of the compressor. Get a reading ? winding is grounded. Then hold meter lead to one terminal and other lead to each other terminal to see if winding is open.

[Bobice]

Inspect the compressor's electrical terminals. Do this by turning off the electricity at the disconnect box. Then remove the cover to gain access to the compressor. In some cases, the fan is connected to the cover. The fan has enough extra wire to allow it to be moved without disconnecting it. Pry open the compressor terminal cover. Check the connections for melted terminals. Melted terminals are a sign of compressor failure.


Test the compressor for a short. First, mark each wire to make re-installation easier. Then remove the wires from the compressor. Turn the multimeter to ohms. Touch the leads together. The meter should beep. Touch one lead to the compressor case, then touch the other lead to each terminal. If the meter beeps at any terminal, then a short is in the compressor. Check the compressor for continuity with the ohm meter. Touch one terminal with one lead. Press the other lead against the other terminals. Do this for every combination. There should be continuity between each. If there isn't, then the compressor is bad.

Edited by Bobice, 04 September 2011 - 06:29 PM.

[tpwu]

Thanks for the detail instructons. The unit is quite heavy for me and is mounted in a wall. I need to get a helper to take it apart. However, by referencing the wiring diagram attached on the unit, I measused the wires and got the readings R-S:3.1, C-S:2.1 and C-R:1.3. I recall the unit tripped the circuit breaker once few days ago. Would the compressor be bad if both capacitor and thermostat are good?

[Dan Webster]

Unplug it and check between the 2 hot prongs on the cord to the frame. If you get a reading you have a short. Slide out the innards enough to remove the cover off the compressor and look for a burnt wire like Bobby said.

[tpwu]

Pulled it out half way and measured all three contacts against the case of the compressor, luckly there are no readings on them.

And there are readings between contacts.

[Dan Webster]

If ya ain't got no shorts piggy back a hard start on the existing cap to give the compressor an extra boost.

Powerstart Hard Start HVAC Booster for SRP6 HS650 WSX-6

[tpwu]

My unit is 24000 BTU and the booster is suitable for compressor 4000 and 12000 BTU, isn't it.

Is the orignal capacitor still good?

[Dan Webster]

Replace the capacitor and see. It should read 45 mfd's on the herm to common side. If it is reading 41 it might not be strong enough to get that compressor going.