AC cycling switch which was to turn the adjustment

[SBL]

After proper service I have great AC cooling but have noticed that there is no cycling.

On the low side, when just starting up, the pressure is 45, which is fine. At 3000 RPM the pressure drops to 25, which for my switch is not quite low enough to turn off the compressor.

On the cycling switch on the accumulator, I noticed that it was loose so tightened it back down (may have been the source of my leak). But anyway, when I remove it and look at the inside, do I turn the little adjustment tab CW or CCW to adjust it so it will cycle the compressor off when I get to 23-25 degrees? Two rather conservative 1/16th inch turns in either direction did not seem to do anything, so rather than go too far thought I would ask.

Steve

[Bitsyncmaster]

You set it so you don't get ice build up on the evaporator. So if your AC keeps cold and you are seeing condensation dripping then your probably good as is. If you seem to loose cooling and after you shut the car off a lot of water drains after sitting then your icing up the evaporator.

My AC won't cycle at idle but does when driving.

[SBL]

You set it so you don't get ice build up on the evaporator. So if your AC keeps cold and you are seeing condensation dripping then your probably good as is. If you seem to loose cooling and after you shut the car off a lot of water drains after sitting then your icing up the evaporator.

My AC won't cycle at idle but does when driving.

Well on most of my other ones, at about 3000 RPM cycling would occur. But not this time. There is a nice puddle of water under the car after I was testing all of this. But then again it is very hot here. Any idea which was to turn it?

And, Hi there Dave. I know I have not been very active over the last 2 years or so. COVID really overworked us Pulmonary and Critical Care doctors over. When I drove mt D I didn't even care if it had AC or not. I was so tired of "fixing up people or things". Coming back now, though.

Steve

[Michael]

With low pressure adjustment, it's all about your pressure and never about RPM or even ambient temp. I have 124a on mine so it's not as warm as R12 and my pressure switch is set to cut the compressor off around 22ish. If you want the compressor to run longer and draw down more (for cooler ac), you will want to turn the adjustment CCW and probably move about 1/8 turn increments, no more than 1/4 at a time though.

[SBL]

With low pressure adjustment, it's all about your pressure and never about RPM or even ambient temp. I have 124a on mine so it's not as warm as R12 and my pressure switch is set to cut the compressor off around 22ish. If you want the compressor to run longer and draw down more (for cooler ac), you will want to turn the adjustment CCW and probably move about 1/8 turn increments, no more than 1/4 at a time though.

Since it is always on, then, I would need to turn it CW then, right? I have RedTek in it which has the same properties, I believe, as R134a.

Steve

[Michael]

Since it is always on, then, I would need to turn it CW then, right? I have RedTek in it which has the same properties, I believe, as R134a.

Steve

Without gauges you are guessing. Not only do they give you live data but will tell you to a degree if there is the proper amount of refringent in the system or if there are any issues like blockages, etc. At idle the compressor is not as efficient than at 50mph with fresh air flowing through the condenser, and it may be normal to run constantly at idle. A different compressor may work fine at idle and still need to cycle which is why monitoring the pressure is really the only way to adjust the low pressure switch.

Yes, to make the system "warmer" or cycle at a higher cutoff point, the adjustment must go CW.

Edit: Just re read your OP and IDK why I thought you didn't have gauges. Must have zeroed in on the no cycling at idle bit. Sounds like you will have it dialed in soon.

[SBL]

Without gauges you are guessing. Not only do they give you live data but will tell you to a degree if there is the proper amount of refringent in the system or if there are any issues like blockages, etc. At idle the compressor is not as efficient than at 50mph with fresh air flowing through the condenser, and it may be normal to run constantly at idle. A different compressor may work fine at idle and still need to cycle which is why monitoring the pressure is really the only way to adjust the low pressure switch.

Yes, to make the system "warmer" or cycle at a higher cutoff point, the adjustment must go CW.

Edit: Just re read your OP and IDK why I thought you didn't have gauges. Must have zeroed in on the no cycling at idle bit. Sounds like you will have it dialed in soon.

OK, will head out and go CW a bit. Just some degree of cycling will be fine, since I know that it should. No big deal if it cycles off a little higher than spec. Just don't want it to freeze up on an evening road trip. Daytime? It is so hot I cannot imagine.
I will let y'all know.
Thanks Michael.

Steve

[David T]

You really can't know what you are doing without putting some gauges on. In a pinch I have used a tire pressure gauge to at least see what the low side is doing. If the pressure gets too high the relief valve will let you know on the high side! It won't (and shouldn't) cycle at idle. In fact, when servicing you are supposed to run at least 1200 RPM, 2,000 is better AND put a fan in front of the radiator. If you are not using -12 you will be running at higher pressures so you do have to adjust the low pressure switch but understand anything other than -12 and you have less cooling capacity, as much as 10% less. To regain that lost capacity you must increase the size of the condenser coil to cool the high side and get the temperatures and pressures down. In Florida I would assume you want all the cooling you can get!