Automotive Air Conditioning Information Forum

Since my 73 Nova with R12 has a newer cycling clutch compressor (R4) and a updated POA valve would it be best to remove the thermostatic cycling switch and install a electric cycling clutch switch in the POA or just keep as is?

Photos would help answer your question. Is the updated POA an eliminator type

Dougflas wrote: ↑Thu Jul 22, 2021 4:32 am Photos would help answer your question. Is the updated POA an eliminator type

I had photos in my other post and added this comment to it but got no replies on it so I went to start a new post with the subject line pertaining to it anyway here is the pics... [/attachment]

Making new threads tends to leave gaps...

https://www.autoacforum.com/viewtopic.php?t=14057

bohica2xo wrote: ↑Thu Jul 22, 2021 5:37 pm Making new threads tends to leave gaps...

https://www.autoacforum.com/viewtopic.php?t=14057

The previous one was about another subject and I added this question to it. Was no longer getting any replies/ and no one answered that part. So started this one with the subject line pointing to my question better. I do appreciate your comments on the other thread though.

So I guess no one knows if any benefit to removing the thermostatic and go with the electric cycling switch? I'll just leave it as is while on r12.

Actually, they're both electrical, just that the existing sensor takes its signal from evaporator temperature and the other from evaporator pressure.

If the R-4 is cycling okay and you're getting nice cool vent temps, I would leave it alone.

JohnHere wrote: ↑Sun Jul 25, 2021 8:57 am Actually, they're both electrical, just that the existing sensor takes its signal from evaporator temperature and the other from evaporator pressure.

If the R-4 is cycling okay and you're getting nice cool vent temps, I would leave it alone.

Its still set up for r12 and right now and it doesn't cycle compressor on/off guessing because it still uses the txv and just bypasses per temps? Think I read somewhere that the older style r12 systems was not a cycling system and when turned on clutch stays on and it just goes in a bypass mode (right term?) . I checked it the other day per sight glass saw no bubbles. I believe temperature as around 89 degrees I watched the gauges looked like low side would go from 50psi to 30psi in about 48 secs then back up to 50 in 12 secs now one time it dropped to 25psi (don't remember if I had a change in rpms on this reading) High side would peak at 205psi and drop to 175 psi. temps thru the center vent with fan on was 60 degress. With rpms at 1500, windows open with a large fan blowing on condenser is. Even took it for a spin and gauge still showed 60 degress.

Thing is as mentioned before the previous owner replace looks like everything on this. The compressor,hoses,dryer are all new and rated for 134a. Its does have a POA Eliminator and new the txv and thermal expansion valve (previous owner had installed). Curious, is there a difference between txv for r12 and r134a? I'm still learning on what whats on this system. Thanks!

Where is the probe going for the preset thermostat? Adjust the probe to the correct position and you should cycle the compressor.

Tim wrote: ↑Wed Jul 28, 2021 7:59 pm Where is the probe going for the preset thermostat? Adjust the probe to the correct position and you should cycle the compressor.

I just checked and its clamped on the line with a hose clamp on the accumulator and had about 1/4 inch thick of cork tape and about 3" of the line. Wouldn't my system still be a non cycling system the way its hooked up and just control the temp via it and the TRX valve? ...Now AC is not my thing but just going by what I've read. Also when I was watching the gauges I notice I would have periods of no flow on the dryer sight glass but compressor was still engaged which also corresponded with the rise and fall of the pressure..