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blown pressure relief valve

sunsites on Tue July 22, 2008 1:48 PM User is offlineView users profile

Year: 1993
Make: Ford
Model: Ranger
Engine Size: 2.3
Refrigerant Type: r-134
Country of Origin: United States

After driving yesterday with everything great, today the unit was blowing hot air, checked the system and the relief valve on the rear of the compressor is open, and is in the open position. Does this mean that the compressor is blown or is it simply replacing the pressure valve.

bohica2xo on Tue July 22, 2008 2:05 PM User is offline

The HPRV's are well known for not resetting or sealing properly when they open. Once they build up a few years of corrosion & crud they tend to jam open when tripped.

Your compressor may be just fine, but you should look for the source of the high pressure spike that opened the valve in the first place. A plugged up air side on the condensor, dead fan clutch, etc. are the usual suspects. Since your compressor managed to push the valve open, it is still pumping at least to 400 psi.

What were the conditions when the valve opened (ambient temp, engine speed, etc.)? It usually makes quite a show when it happens. Should be some oil spread around too.

Once you detremine the cause of the high pressure event & correct it, you should flush the system and install a new drier before refilling.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

sunsites on Tue July 22, 2008 2:14 PM User is offlineView users profile

I'm not sure when it happened, like I said all was well yesterday, it was hot, 98 with high humidity, the system is two years old (8-2006), and has worked perfectly. Can relief valves be purchased, it looks to be a screw in type of valve.

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