Re: Question for those knowledgable about compressors
[Re: Ronnman]
#3074338
09/04/22 11:55 PM
09/04/22 11:55 PM
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Joined: Jan 2003
Posts: 10,707 North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,707
North Dakota
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What brand/model of compressor do you have? My 5 hp Saylor-Beall knockoff does not have that.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: Question for those knowledgable about compressors
[Re: 6PAX]
#3074347
09/05/22 12:18 AM
09/05/22 12:18 AM
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Joined: Jul 2005
Posts: 707 California
BigDaddy440
super stock
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super stock
Joined: Jul 2005
Posts: 707
California
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I just went through the same or similar situation with my 60 gallon Dewalt Compressor. All these compressors have a check valve threaded into the tank, it allows air to flow from the compressor pump into the tank, but will not allow it to flow back out of the tank toward the pump. If this check valve gets stuck open the compressed air will move backwards toward the pump and forced through a tube and escape out a port meant to release pressure in the case of a check valve failure. This port IS NOT the HIGH PRESSURE safety release valve that opens in the case the tank pressure becomes unsafe.
Your problem sounds exactly like a check valve failure.
Check valves can fail on their own, but in my case, my year old compressor had a reed valve break which pushed debris into the check valve and caused it to sick open.
I replaced both my Check Valve and then my Valve Plate to resolve my issue.
Hope this helps.
1969 A12 Roadrunner 1970 Plymouth Cuda 1968 Dodge Dart
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Re: Question for those knowledgable about compressors
[Re: BigDaddy440]
#3074371
09/05/22 05:31 AM
09/05/22 05:31 AM
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Joined: Jan 2003
Posts: 10,707 North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,707
North Dakota
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I just went through the same or similar situation with my 60 gallon Dewalt Compressor. All these compressors have a check valve threaded into the tank, it allows air to flow from the compressor pump into the tank, but will not allow it to flow back out of the tank toward the pump. If this check valve gets stuck open the compressed air will move backwards toward the pump and forced through a tube and escape out a port meant to release pressure in the case of a check valve failure. This port IS NOT the HIGH PRESSURE safety release valve that opens in the case the tank pressure becomes unsafe.
Your problem sounds exactly like a check valve failure.
Check valves can fail on their own, but in my case, my year old compressor had a reed valve break which pushed debris into the check valve and caused it to sick open.
I replaced both my Check Valve and then my Valve Plate to resolve my issue.
Hope this helps.
Not to be a PITA but I think what you were hearing was air escaping from the unloader valve. When the compressor shuts down, the main line check closes and the unloader valve opens to de-pressurize the compressor. That way when it starts, it's starting against no pressure. Depending how the unloader valve is configured, it will then shut and the compressor begins operating. If the main line check fails but the unloader valve operates, there will be air discharged from the unloader when the compressor stops until the tank is empty.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: Question for those knowledgable about compressors
[Re: 6PakBee]
#3074452
09/05/22 12:06 PM
09/05/22 12:06 PM
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Joined: Jan 2003
Posts: 25,757 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,757
Rio Linda, CA
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The unloader is usually operated via a centrifugal valve in the crankcase but I think what you're seeing is the compressor head over-pressure relief valve which opens at a much higher pressure than the tank relief valve. Is the escaping air a steady stream or does it pulse?
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Re: Question for those knowledgable about compressors
[Re: BigDaddy440]
#3074522
09/05/22 04:16 PM
09/05/22 04:16 PM
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Joined: Jan 2003
Posts: 4,142 Canada -- Posts: 4034 -Registe...
5thAve
Doesn't care what this says anyway
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Doesn't care what this says anyway
Joined: Jan 2003
Posts: 4,142
Canada -- Posts: 4034 -Registe...
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Is that part with the arrow similar to the same one that looks like it on the other side with the green end? I haven't seen those on any compressor I've dealt with before and hard to see from the pics what they are. I just went through the same or similar situation with my 60 gallon Dewalt Compressor. All these compressors have a check valve threaded into the tank, it allows air to flow from the compressor pump into the tank, but will not allow it to flow back out of the tank toward the pump. If this check valve gets stuck open the compressed air will move backwards toward the pump and forced through a tube and escape out a port meant to release pressure in the case of a check valve failure. This port IS NOT the HIGH PRESSURE safety release valve that opens in the case the tank pressure becomes unsafe.
Your problem sounds exactly like a check valve failure.
Check valves can fail on their own, but in my case, my year old compressor had a reed valve break which pushed debris into the check valve and caused it to sick open.
I replaced both my Check Valve and then my Valve Plate to resolve my issue.
Hope this helps.
A lot of those check valves have a hex part you can unscrew to take it apart to clear them. There's big rubber seal and spring inside so it's pretty easy to take apart and put back together. One of my compressors had a problem when I first got it where there was a bunch of goop inside it on the seal that was stopping it from closing all the way.
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Re: Question for those knowledgable about compressors
[Re: John_Kunkel]
#3074576
09/05/22 07:44 PM
09/05/22 07:44 PM
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Joined: Jan 2003
Posts: 5,614 Detroit area
6PAX
OP
master
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OP
master
Joined: Jan 2003
Posts: 5,614
Detroit area
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The unloader is usually operated via a centrifugal valve in the crankcase but I think what you're seeing is the compressor head over-pressure relief valve which opens at a much higher pressure than the tank relief valve. Is the escaping air a steady stream or does it pulse? It is a steady stream. There is a small hole on the face of it where you see the black sticker but that is not where the air is coming out. It's coming out on the side or from the threads where it screws into the pipe.
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Re: Question for those knowledgable about compressors
[Re: 6PakBee]
#3074582
09/05/22 07:54 PM
09/05/22 07:54 PM
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Joined: Jan 2003
Posts: 5,614 Detroit area
6PAX
OP
master
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OP
master
Joined: Jan 2003
Posts: 5,614
Detroit area
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What brand/model of compressor do you have? My 5 hp Saylor-Beall knockoff does not have that. It is a U.S. General model US7580V.
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