Whining Noise From Air Compressor
#1
07-12-18, 04:23 PM
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Whining Noise From Air Compressor
I have a harbor freight air compressor #90234 that's about eight years old. Recently, the compressor would make a high pitched noise(much like a whine type noise) upon startup and continue. The compressor only fills about a 1/4 of the way and keeps running but not filling with that whine not going away. Any ideas on what to look at? Many thanks. Don
#2
07-12-18, 04:58 PM
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Sounds like the tank check valve is not closing. When you shut it off does air continue to leak out?
Check part #57. https://www.about-air-compressors.co...iles/90234.pdf
See if it's got a needle valve on the side of it that vents during startup... and see if you can push in with your finger, then let up on it. If so, fiddle with it while it's trying to pump up to pressure. Sometimes they get dirty then get stuck open.
Check part #57. https://www.about-air-compressors.co...iles/90234.pdf
See if it's got a needle valve on the side of it that vents during startup... and see if you can push in with your finger, then let up on it. If so, fiddle with it while it's trying to pump up to pressure. Sometimes they get dirty then get stuck open.
#3
07-12-18, 06:31 PM
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#4
07-12-18, 07:15 PM
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Yes, if the "whining sound" is the whistle of air escaping from that valve that is supposed to shut once it reaches 30 or 40 lbs... that's what it's designed to do... open during startup, then close once it reaches a certain psi.
Narrow down where the noise is coming from. Take a length of hose or a long tube of some type (like a shop vac hose) and hold one end up to your ear like a stethoscope to locate the source of the whine.
if it's a screaming sound coming from the head, it might be that your piston rings are shot and you've just lost compression as a result.
Narrow down where the noise is coming from. Take a length of hose or a long tube of some type (like a shop vac hose) and hold one end up to your ear like a stethoscope to locate the source of the whine.
if it's a screaming sound coming from the head, it might be that your piston rings are shot and you've just lost compression as a result.
#5
07-14-18, 07:51 PM
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I think I am going to just replace both the check valve and the pressure switch. That way I know the issue will be solved without any other thought. Now, just need to find the parts. I know I can get the check valve from HD's website, but I just need to locate the pressure switch.
#6
07-15-18, 05:24 AM
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I had just purchased this last night:https://www.ebay.com/itm/Air-Compres...53.m2749.l2649.
It reads exactly the same as my original does on the top. But on the tank of my comp(and in the manual), it tells me that the auto restart is 85psi and the auto shutoff is 115psi. This pressure switch description says 90-120 in the heading, but like I said, all the numbers on the top of the switch are identical with the original and the new. did I purchase the wrong one or are they adjustable?
It reads exactly the same as my original does on the top. But on the tank of my comp(and in the manual), it tells me that the auto restart is 85psi and the auto shutoff is 115psi. This pressure switch description says 90-120 in the heading, but like I said, all the numbers on the top of the switch are identical with the original and the new. did I purchase the wrong one or are they adjustable?
#8
07-15-18, 05:47 AM
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But if this new one says 90-120 and on the tank and the manual says 115, if the psi goes past 115 cant that blow the comp tank or anything? I fear that.
#9
07-15-18, 06:02 AM
They err on the side of caution when they rate the tank. Also there is a pop off valve that prevents the tank from bursting if the pressure gets above a certain point. Your pop off valve is probably set to go off at 125 psi. I have a Craftsman 1hp compressor that I bought about 35 yrs ago. I bumped the pressure switch up from 85/115 to 90/120 shortly after I bought it. The only issue I ever had was if I left the compressor on the back of the truck exposed to an overnight frost - which made the pop off valve go off until the compressor warmed things up.
#10
07-15-18, 05:27 PM
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Very interesting video. Kinda gives you a wakeup call: https://www.youtube.com/watch?v=KVP_A7eGYxw
