View Full Version : A/C gurus needed
RF Overlord
07-14-2013, 11:22 AM
Problem with my Grand Ma: A/C will blow cold and dry, then kind of luke-cool and humid...then cold and dry again...over and over.
Bought some gauges and this is what I get:
With the compressor running, the high side goes to about 170 psi and holds, while the low side slowly drops from about 35 down to about 22...the compressor then kicks out for 6-8 seconds, the high side drops to 125 and the low goes up to about 40, then the compressor kicks back in. Over and over.
Ambient temp is about 80° and humid. I know the pressures will vary with temperature and humidity, but should it be cycling like that? My house window AC will keep the compressor on until the thermostat is satisfied.
Krytin
07-14-2013, 01:52 PM
Sounds like a low charge of freon.
When the low side drops, the pressure switch on the compressor drops out the electric clutch. The high side holds pressure while it's running because the freon is going through the expansion valve. As the pressure equalizes the low side comes up and the clutch /pressure switch comes back on. You can give it a quick shot of freon to confirm this.
You may want to check the receiver/dryer as your first stop looking for a leak.
Sounds like a low charge of freon.
When the low side drops, the pressure switch on the compressor drops out the electric clutch. The high side holds pressure while it's running because the freon is going through the expansion valve. As the pressure equalizes the low side comes up and the clutch /pressure switch comes back on. You can give it a quick shot of freon to confirm this.
You may want to check the receiver/dryer as your first stop looking for a leak.
Agreed :beer:
RF Overlord
07-14-2013, 03:00 PM
Thanks, guys.
Everything I've read on the interwebs says either "it's low on refrigerant" or "it's normal".
There's a radiator shop not too far from me that been very good to me a few times in the past. I think I'll just take it in and have them evacuate and recharge it.
Krytin
07-14-2013, 04:03 PM
Thanks, guys.
Everything I've read on the interwebs says either "it's low on refrigerant" or "it's normal".
There's a radiator shop not too far from me that been very good to me a few times in the past. I think I'll just take it in and have them evacuate and recharge it.
Yep, have them use the U/V dye to look for any potential leaks down the road!;)
martyo
07-14-2013, 07:06 PM
Low freon. Not terribly low, but low nonetheless.
The big determining factor is how long from the time the clutch engages until it disengages. At 80 degrees, the fan on high, it should take a long time. If it is only a few seconds before it kicks off then it is low.
Powered by vBulletin® Version 4.2.5 Copyright © 2025 vBulletin Solutions Inc. All rights reserved.