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Can you bench test an A/C EPR valve? #2611767
01/24/19 08:05 PM
01/24/19 08:05 PM
Joined: Feb 2006
Posts: 256
New Jersey
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69Chrgr Offline OP
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69Chrgr  Offline OP
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Rebuilt my RV2 compressor, and when I done, I hooked it up to a Dewalt drill and spun the compressor. I realized right away that it started to push air out the front the stopped, I checked the rear port and it had no intake. When I removed the EPR valve the compressor seemed to work fine, pulled a good suction on the intake and pushed air out of the front. I am know wondering if the EPR valve is bad. should it be closed at room temp and bench testing? I don't really want to buy one if I have a good one, but Im not really sure how to test it without putting it in the car and charging it.

And I do plan on using R12, thats why I didn't remove it

any help would be appreciated


Thanks

Duane

Re: Can you bench test an A/C EPR valve? [Re: 69Chrgr] #2612236
01/25/19 07:57 PM
01/25/19 07:57 PM
Joined: Jan 2003
Posts: 22,165
Rio Linda, CA
John_Kunkel Offline
Much ado about nothing
John_Kunkel  Offline
Much ado about nothing

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Posts: 22,165
Rio Linda, CA
The FSM doesn't show a bench test, the only to test it is in operation with a special 3-gauge manifold that monitors the pressure drop across the evaporator.


I'm supposed to respect my elders, but its getting harder and harder for me to find one now.
Re: Can you bench test an A/C EPR valve? [Re: John_Kunkel] #2612284
01/25/19 09:43 PM
01/25/19 09:43 PM
Joined: Feb 2006
Posts: 256
New Jersey
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69Chrgr Offline OP
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69Chrgr  Offline OP
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New Jersey
I actually found out what I was thinking was wrong. When I spun the compressor by a drill, it acted like the EPR valve was stuck closed. you wouldn't get any out put from the front after 5 or 10 seconds, and when I removed the valve, it was fine. Not knowing when it is suppose to be closed, I had no idea if it was any good. I took the Valve out of another compressor that I have that I know worked when I had it in the car, and it worked how I thought it should. That doesn't mean the valve is good, but it means it's not stuck.

Duane

Re: Can you bench test an A/C EPR valve? [Re: 69Chrgr] #2613668
01/28/19 08:21 PM
01/28/19 08:21 PM
Joined: Jan 2003
Posts: 1,197
Slidell, LA
Ronnman Offline
super stock
Ronnman  Offline
super stock

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Posts: 1,197
Slidell, LA
The EPR is designed to keep a minimum pressure of about 30 psig in the evaporator to keep the refrigerant temp above freezing. This means it will shut off the port to the compressor until the pressure in the suction line, from the evaporator, rises to 30 psig. So at atmospheric pressure the EPR would be shut and turning the compressor would pull an vacuum inside the compressor thus result in little flow out the compressor discharge. The only way the “bench test” would be to rig up an old compressor suction fitting and setup a means to add pressure to the fitting. It’s just not to very feasible.
Ron

Re: Can you bench test an A/C EPR valve? [Re: Ronnman] #2613795
01/29/19 12:34 AM
01/29/19 12:34 AM
Joined: Aug 2005
Posts: 282
Hinckley, Ohio
KWF340 Offline
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Hinckley, Ohio
I went through this exercise about a year ago and I could not find any way to test the EPR valve outside the system. As stated above, the valve can be tested when in the system based on pressure readings, but that means the system has to be charged. The last thing you want to find out when restoring the AC system is that the EPR valve is bad AFTER the system has been charged.

Also, based on what I’ve been told Mopar EPR valves have a shelf-life when not in a working system (even unused “never been out of the box” NOS valves will go bad over a period of time). Since the original Mopar valves haven’t been made in years, there is a good chance that many/most of the NOS valves out there are bad.

So if the valve is in an unknown condition, then I would just buy a repro valve as cheap insurance.

Repro EPR valve

Last edited by KWF340; 01/29/19 12:35 AM.

1969 Super Bee, 383, 4-speed, T5;
1969.5 Road Runner, 440-6, 4-speed, 96;
1970 Duster 340, 4-speed, EV2;
1970 Charger R/T SE, 440 (496), Auto, EB3;
1970 Dart Swinger 340 (416), 4-speed, EV2;
1970 Corvette coupe, LS5, 4-speed, Daytona yellow;
2000 Corvette coupe, LS1, 6-speed, Twin Turbo, Torch red.
Re: Can you bench test an A/C EPR valve? [Re: KWF340] #2613802
01/29/19 12:46 AM
01/29/19 12:46 AM
Joined: Aug 2005
Posts: 282
Hinckley, Ohio
KWF340 Offline
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Hinckley, Ohio
Some additional information here.

EPR

Last edited by KWF340; 01/29/19 12:48 AM.

1969 Super Bee, 383, 4-speed, T5;
1969.5 Road Runner, 440-6, 4-speed, 96;
1970 Duster 340, 4-speed, EV2;
1970 Charger R/T SE, 440 (496), Auto, EB3;
1970 Dart Swinger 340 (416), 4-speed, EV2;
1970 Corvette coupe, LS5, 4-speed, Daytona yellow;
2000 Corvette coupe, LS1, 6-speed, Twin Turbo, Torch red.
Re: Can you bench test an A/C EPR valve? [Re: 69Chrgr] #2614398
01/30/19 01:21 AM
01/30/19 01:21 AM
Joined: Feb 2006
Posts: 256
New Jersey
6
69Chrgr Offline OP
enthusiast
69Chrgr  Offline OP
enthusiast
6

Joined: Feb 2006
Posts: 256
New Jersey
Thanks, Guess Ill get a repro one to start with a new one.

Duane







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