New Compressor cycling question
Tinkerin_wit_tools
08-21-2011, 05:14 PM
After replacing all necessary components of a/c system in my wife's 99 Blazer, I still have one question. A friend helped me do this on my car a few months back, but am not able to get a hold of him to ask. Well, everything said and done, I evacuated system with pump for recommended time from manual of the unit, then filled it up with freon. It began to cycle on and off and eventually never stopped. Granted, it is pretty hot out today and condensation built up on dryer quickly. Just used to it(mine, that is) cycling on and off every so often, but this never stopped it's cycle. Blowing cold as ice, no leaks in system, so all is right, right? For those of you curious, it was brand new compressor, and pre-oiled. Is everything copasetic if the manifold gauges are reading the way they should?:eek7:
brcidd
08-21-2011, 05:29 PM
If I read your post right you are concerned that the compressor is not cycling under high heat load- correct? This is perfectly normal. Compressor shall only cycle when suction pressure drops and this only happens under low heat load - you change heat load by lowering blower speed inside the cabin. High blower at 85 degf- no cycling would be normal, switch to low speed blower and recirc-- cycling would be normal....
gmtech1
08-21-2011, 05:34 PM
Check you're low side pressure and make sure the cycling switch is not stuck. It should cycle off somewhere around 20-25psi. If it's not pulling that low and the dryer isn't freezing over, drive it.
Tinkerin_wit_tools
08-22-2011, 06:14 AM
If I read your post right you are concerned that the compressor is not cycling under high heat load- correct? This is perfectly normal. Compressor shall only cycle when suction pressure drops and this only happens under low heat load - you change heat load by lowering blower speed inside the cabin. High blower at 85 degf- no cycling would be normal, switch to low speed blower and recirc-- cycling would be normal....
Blower speed inside cabin was at max and didn't change it when I tested it yesterday. Since I won't be driving the car until next week, I will ask my wife how it is. Unfortunately, she never listens or pays attention to what noises and smells come from the car while driving, she just drives it. Thanks to help set my mind at ease.:biggrin:
Blower speed inside cabin was at max and didn't change it when I tested it yesterday. Since I won't be driving the car until next week, I will ask my wife how it is. Unfortunately, she never listens or pays attention to what noises and smells come from the car while driving, she just drives it. Thanks to help set my mind at ease.:biggrin:
Tinkerin_wit_tools
08-22-2011, 06:19 AM
Check you're low side pressure and make sure the cycling switch is not stuck. It should cycle off somewhere around 20-25psi. If it's not pulling that low and the dryer isn't freezing over, drive it.
Pressure on the gauges read what they should read. As for the switch, well, just to be safe, I not only replaced that switch, but the one on the dryer as well. Only had the car running at Max A/C for about 15 minutes and didn't drive it. I will have to check it out again this next coming weekend when my wife hands back control of the car after her work week for me drive. Thanks for the input, so if you don't hear back, then all is well.:cool:
Pressure on the gauges read what they should read. As for the switch, well, just to be safe, I not only replaced that switch, but the one on the dryer as well. Only had the car running at Max A/C for about 15 minutes and didn't drive it. I will have to check it out again this next coming weekend when my wife hands back control of the car after her work week for me drive. Thanks for the input, so if you don't hear back, then all is well.:cool:
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