Tools, Sharpening and Power Machinery - Air Compressor strains to re-start above 70 lbs.
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Chip6565
11-29-08, 06:33 PM
I have a piston type single stage Sears compressor that strains to re-start unless it has no air in the tank.
It appears that the tank pressure is acting upon the compressor making it difficult for it to re-start once it has over 70 or so pounds of pressure in the tank.
I removed the check valve and it appears to be functioning properly. The spring was working and the valve was not stuck. Wondering if the problem is in the reeds/head?:wall:
It appears that the tank pressure is acting upon the compressor making it difficult for it to re-start once it has over 70 or so pounds of pressure in the tank.
I removed the check valve and it appears to be functioning properly. The spring was working and the valve was not stuck. Wondering if the problem is in the reeds/head?:wall:
GregH
11-29-08, 08:33 PM
In addition to the check valve there is an unloader valve on the pressure switch.
This valve should open to drain the pressure each time the pressure switch cycles.
To test the check valve, run the compressor until the pressure builds up and the motor stops.
Unplug the compressor and CAREFULLY loosen the line to the tank at the compressor.
The pressure should bleed only until the line empties.
If the tank drains then the check valve is leaking.
This valve should open to drain the pressure each time the pressure switch cycles.
To test the check valve, run the compressor until the pressure builds up and the motor stops.
Unplug the compressor and CAREFULLY loosen the line to the tank at the compressor.
The pressure should bleed only until the line empties.
If the tank drains then the check valve is leaking.
waterwelldude
11-29-08, 09:20 PM
Something else to look for. Low voltage. Have you done any wiring? maybe add a few plugs or more lights? I had a similar issue with mine.
Turned out to be low voltage. I added some lights, and tied into the same line as my compressors.
The lights were taking power away from the compressor. When it had pressure on it. It would not restart. If I turned off the new lights, it would start fine.
Travis
Turned out to be low voltage. I added some lights, and tied into the same line as my compressors.
The lights were taking power away from the compressor. When it had pressure on it. It would not restart. If I turned off the new lights, it would start fine.
Travis
Inthetrees
12-10-08, 10:43 AM
I'm having the same problem with my compressor.
It builds pressure to about 50psi, then the motor starts to strain. When I shut it off, it struggles to restart and the belt slips. At this point I can barely even turn the compressor wheel by hand.
So, the problem is likely the unloader valve?
I have this Square D pressure switch. Which part is the unloader valve?
http://www.drillspot.com/pimages/2665/266549_300.jpg
http://www.drillspot.com/pimages/2665/266546_300.jpg
Thanks,
Joe
It builds pressure to about 50psi, then the motor starts to strain. When I shut it off, it struggles to restart and the belt slips. At this point I can barely even turn the compressor wheel by hand.
So, the problem is likely the unloader valve?
I have this Square D pressure switch. Which part is the unloader valve?
http://www.drillspot.com/pimages/2665/266549_300.jpg
http://www.drillspot.com/pimages/2665/266546_300.jpg
Thanks,
Joe
markiz37
12-10-08, 04:30 PM
Bottom pic, lower left is the connection for the valve. The valve itself is a needle type activated as current cuts out. If you know you have a faulty unloader, just get a new pressure switch.
Aeroplay
02-23-09, 04:39 AM
Sometimes people think it is the unloader that is at fault when it continues to bleed after the compressor shuts off. This is not the case. The thing to ask yourself is, where is this air coming from? The compressor isn't running, so it must be the tank via the check valve. So the correct diagnosis is, the check valve is at fault.
Herb:)
Herb:)
mikeTN
02-23-09, 03:07 PM
I have a piston type single stage Sears compressor that strains to re-start unless it has no air in the tank.
It appears that the tank pressure is acting upon the compressor making it difficult for it to re-start once it has over 70 or so pounds of pressure in the tank.
I removed the check valve and it appears to be functioning properly. The spring was working and the valve was not stuck. Wondering if the problem is in the reeds/head?:wall:
Could this be a 220v. comp. running(or attempting to) on 110v.? Have you checked the capacitor for the re-start problem? I am thinking unloader valve not unloading!?
It appears that the tank pressure is acting upon the compressor making it difficult for it to re-start once it has over 70 or so pounds of pressure in the tank.
I removed the check valve and it appears to be functioning properly. The spring was working and the valve was not stuck. Wondering if the problem is in the reeds/head?:wall:
Could this be a 220v. comp. running(or attempting to) on 110v.? Have you checked the capacitor for the re-start problem? I am thinking unloader valve not unloading!?