A/C Compressor not cycling???

monte87

Founding Member
Feb 26, 2001
876
16
49
new york
Greetings guys-

It seems after boosting my A/C with some good ole original R12, My compressor does not seem to cycle on and off anymore like it use. I do know-When it cycles constant the system is low, which caused my warm air syndrome (Lack of freon). Grant it-Now i have ice cold A/C but from what i see, The comporessor doesnt cycle at all anymore. What can cause this????
i also understand the concept of the low pressure swicth, preventing the compressor from burning out when there isnt enough freon in the system Would a bad LPS cause the system/compressor not to cycle at all?

Thanks you in advnace for your replies in advance!
Anthony :nice: :flag:
~SEMPER FI~
 
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There is lots of R12 out there, they just dont make it anymore. And to buy whatever is out there-You need top be MVAC EPA 609 cert. I think mexico still makes R12, only until this year-or something like that, im not 100% sure though,

Later Ant
 
If you charged it too much, the low side doesnt pull down far enough to kick the LPCS off. Then the compressor runs non-stop.

Watch for evap freezing or risking the blowing of a seal.
 
If you charged it too much, the low side doesnt pull down far enough to kick the LPCS off. Then the compressor runs non-stop.

Watch for evap freezing or risking the blowing of a seal.


How do i go about correcting this? The low pressure side read 38psi on the gauge-that is when i pulled the freon off. Thought it was pretty much done.

Hit me back, Thnaks Anthony
 
How do i go about correcting this? The low pressure side read 38psi on the gauge-that is when i pulled the freon off. Thought it was pretty much done.

Hit me back, Thnaks Anthony

What was the ambient temp when you checked pressure? Can you see high-side pressure (you need a set of manifold gauges)? Both are very important things to consider when noting charges pressures.

38 PSIG should give a high side pressure of over 300 PSIG in nearly 120*F ambient temps.

If it's 100*F outside, generally you would have wanted to be closer to 25 PSIG. When it comes to being overcharged, I worry about high-side pressure more than low-side pressure.
 
At the time of charging in the early a.m. in NYC was about 80 with hugeeeeeee humidity, But the daytime high was 88 again with hugeeeeeeeeeeeeeee humidity, making it feel like it was 95.
I was following info stating when adding 2 cans of gas the high side will read about 250-300 psi and the low side about 28-38psi which would be considered normal.
On another side note-I have a HVAC mechaincal temp gauge/probe in the vent and it read 45 on its lowest and about 50 coming out the vent.

Whatta ya think, Hit me back please,
Many Thanks Anthony

What was the ambient temp when you checked pressure? Can you see high-side pressure (you need a set of manifold gauges)? Both are very important things to consider when noting charges pressures.

38 PSIG should give a high side pressure of over 300 PSIG in nearly 120*F ambient temps.

If it's 100*F outside, generally you would have wanted to be closer to 25 PSIG. When it comes to being overcharged, I worry about high-side pressure more than low-side pressure.
 
id say your overcharged a little too... if you use a PT chart(Pressure Temperature chart) for charging R-12, it will tell you that at 80*f your pressure should read about 26.7psi properly charged and about 37 at 100*f... do your saying your at 38psi at only 80 which is a bit high...you can also go by your air coming off of the evaporator coil...45 is pretty good but if you pull out a little refrigerant it may go up a little... if your looking for a pt chart just google R-12 PT Chart... hope that may help you...

Jim