Compressor on with one can of refrigerant…

[rockR67]

Hi all,

I’ve worked on a few AC systems before but never had this. Replaced the front evaporator (not fun), accumulator, new orifice tube and added oil to everything as specified in the manual. Pulled a vacuum and after a good measure of time (1.5 hrs), started to put r134a in.

Compressor turned on with 1 can and kept running, pressures were legitimately high enough to turn it on too. No cool air blowing front or rear on the suburban. I was reluctant to just try and keep pushing more 134 in since this behavior feels off. I expected the compressor to cycle, and at least not until the second can. Very strange to me but it’s also the first of these systems I’ve worked on. Others were all R12 retrofits.

So did I screw up the charge somehow? Or introduce a line block somehow?

Thoughts welcome, I’m happy to feel stupid - especially if something easy to fix comes to mind out there.

 

[GoToGuy]

Nope, if the pressure, by can filling, builds enough to close the low pressure switch, Shazam, now it like some leaked out and your gonna continue filling to the charted pressures. It runs continuously at this point because vapor quantity is so low, as you continue, the compressor will cycle at a slower rate. And you notice cooler duct temps. On the way home 2 days ago mine got down to 48° F.

 

[rockR67]

Okay, thanks. It is dang hot here in Louisiana so I suppose that dropping the one can in went all vapor and no liquid and hit the magic vapor pressure at the LP Accumulator switch too. I’ll see if I can get some more in it and take it from there.

Side thought- does it seem like the only time to work on the trucks is during awful weather for anyone else too? Fuel pumps, AC, etc.

 

[rockR67]

Made some progress - running about 320psi high side at 100F ambient. Maybe a little low still at this point (350psi being about right)? The cool air inside is "okay" but no one would call it cold. Still, it's 100F outside and it was at least adequate, so I'm not sure how great to expect it anyway. Thoughts welcome as always, thanks for the input.

You must be registered for see images attach

 

[GoToGuy]

Think of the cooling is a balancing act. If it has the ability to take 50° off the incoming outside air temp then 110° outside could be chilled to 60° . And 100° to 50° . The heat exchange cooling is a trade off , outside air and humidity affect how much cooling you can get. Also 134 is not quite as good as R12 was.when serviced mine a couple weeks ago, was same days we were having 6 days of 101° to 107° . So I was getting heat from family to FIX the air. Here is chart based on local temps , and manifold pressures, what temp you see in center vents.

You must be registered for see images attach

 

[Wildblue19]

Think of the cooling is a balancing act....

Is that service manual in one of the downloadable ones on this site? Was looking for it but couldn't find the manual with A/C troubleshooting in it.

 

[GoToGuy]

It's the '95 service book 1/ section 1 A all heating, section 1B all ac, yes it in the link with a lot others