A/C Popping off

[flattopwill]

Hey guys I got an old r-4 pancake compressor mounted on my 5.3 and I'm trying to get everything working after not having it for a few years.

I replaced the condenser, drier, orifice tube, and high side line. I got the compressor from a salvage yard. It appears to be a reman from CompressorWorks in Dallas TX. We converted the system to R134A.

Before the first charge, my friend who is an ac tech pulled a vacuum for 30 mins. Then, charged to 2.5lbs. Equalizes to about 85-90psi when off. Low side is around 50psi and the high side is about 350-450psi when running. My tech buddy said the high side is climbing too high too quickly.

I have two Hayden 14" electric fans on the radiator that keep the engine plenty cool. I've only been running the AC when the truck is moving +30mph. The high side still over pressurizes and pops the safety valve.

Is there something wrong in my system or is there just not enough cooling on the condenser? I can't believe +30mph headwind won't keep the condenser cool when people sit with their car idling and the ac on for long periods of time.

IT'S HOT! PLEASE HELP!

 

[DRAGGIN95]

I am sure someone will have some sort of helpful comment here! I haven't ever run on to that problem before. I will be interested to hear the fix for this as well.

 

[shelbyt.67]

I just fixed all that Sheeot. Replaced everthin but the hoses and evap under the dash. Cleaned the evap and hoses REAL good. Had a problem with a new reman compressor not cycling on with full fill. Turned out I failed to replace the pressure switch on the dryer/collector. The R-134 is higher pressure than the R-12 and the original switch was made for R-12 only. Would'nt work with 134. Also blew out the original high side schraeder valve so it got replaced with the proper R134 fitting. Had it on for a couple days now. So far so good.
It sounds like u got a blockage somewhere or that compressors not right.

 

[flattopwill]

Found this today.

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This orifice tube was new a week ago. The top was completely broken and the rest was covered in metallic sludge. I think this came from my old compressor. I just hope there isn't more of this in the system. We replaced the orifice tube and flushed/blew out the condenser as much as we could. I think it's fixed now. The pressures were much lower. At idle the high side hovered around 300psi. I just drove around town for about 45 mins afterward and had no problems. It blew cold air and never popped the valve so I think it's good to go now.

 

[DRAGGIN95]

Yeah that was pretty bad!

 

[shelbyt.67]

Thats what they call "Black Death". Dude, U really need to start over and flush the crap out of the entire system. I would buy a new compressor. That is a sign of serious trouble to come.

 

[Mik3]

Not always, shelby. The orifice is made to filter out all contaminants. If his system isn't ed by now, then it's probably going to be okay. None of the shavings got to the compressor because the orifice blocked them. Just change the orifice about 3 times this month, or until they start coming out clean. If I were you though, I'd flush the lines that are easiest, the one going from the compressor to the condenser, and the one going from the evaporator to the compressor. Then there's also the one going from the accumulator to the evaporator.

 

[shelbyt.67]

Well, do what u will. The orifice tube is not a filter, it is a screen. Its main function is a pressure valve and does not filter ALL contaminants. Its filtering function is no better than the fuel screen on yer fuel pump. I'm just sayin from personal experience and a lot of research.

 

[frito-bandito]

Damn dude, definitely flush the hell out of those lines. Also check and make sure that your new compressor ain't causing that.

 

[SAATR]

My main concern would be the source of those particles. If you didn't flush the system when all of your components were replaced then it is entirely possible that the contaminants were drawn through the compressor from the low side and then pushed into the condenser and orifice tube. The other option is that the used compressor is failing and pushing contaminants through the condenser which are then trapped by the orifice. I would recommend evacuating and completely flushing the system, and replacing the orifice and dryer again. Only then can you be sure of the source of the particles, which could only come from the compressor at that point. Only under the most dire of circumstances would I ever recommend a junkyard compressor, and have never personally had one work flawlessly. In all honesty, reman units can be sketchy, with the price difference rarely making them worthwhile. Mik3's suggestion of replacing the orifice could certainly work, but I think that it would be a better investment of time and money to flush the system thoroughly, replace the components, and not worry about it.