compressor bogs down at 20lb

by Scott
(Coraopolis PA)

When I turn the compressor on it builds to 20lbs and then the motor bogs down and wont kick out. There is a new pressure switch on it. They compressor sat for years without runnning so I drained the oil and refilled it. It still does the same thing. Any ideas.

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Scott,

Are you saying that it worked fine after the many years of sitting, or are you saying that the first time you used it since it sat, it bogs down at 20 PSI?

Make sure your compressor is getting clean power, no extension cords, and check the intake filter to make sure it is clean as well.

More info, please. What make of compressor, what model number and what voltage?

Bill

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Aug 05, 2012
compressor
by: scott

it worked fine then it started not kicking on sometimes, when it would kick on it would run fine sometimes but sometimes it acts like its under a load. the motor runs very slow and hums.......
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Power supply issue perhaps. Check the caps (see that page) and tell us the make and model please.

B.

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When compressor does kick on, it sounds like the motor is bogged down

by Michael Byrd
(Lookout Mtn, Ga)

2hp motor air compressor. Intaily builds pressure to 115 psi. After it turns offand sits, does not look or lose pressure .

When compressor does kick on, it sounds like the motor is bogged down and never builds pressure back. Stays around 20-30 psi and won't build past this amount UNLESS I unplug the power cord and plug it back in.

I can't find any leaks and upon checking the reed/ flappers.

I now smell burnt oil, the top of the valve smokes from burning oil and its very hot. So hot it melted the plastic threads on the filter housing!

So, I imagine I didnt install the roads correctly . do I need a new reed/ flap set? Why will compressor build 1115 psi and then not unless power is disconnected.

I can't afford a new ,used one and really need this air compressor to finish siding my home for homeowners. Any help is most greatfully appreciated.
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Michael, you don't indicate what the power supply is. Tell me about the extension cord you are using. That may be an issue.

That your motor is overheating suggests that you've got...

a) a power supply problem
b) a motor problem
c) a start / run capacitor problem
d) an unloader valve that isn't working properly
e) a valve / gasket problem

Bill

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Jun 21, 2014
power supply
by: Michael Byrd

Power supply is 115 . Extension cord is rated for 15 amps (14 awg), but is past its life. I did plug compressor directly into duplex receptable and still had same results. Motor sounded to be running correctly ( no bogging) but would not build past 50 psi. I also still smell burnt oil. Air does not come out of intake filter while running.???
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The cord may be rated for 15 amps, but you lose current over distance, and though the cord can handle 15 amps, no guarantees about what is actually getting to the compressor. No extension or a heavy duty (in my opinion maximum 25') extension cord. As noted on this website, use a longer air hose, NOT an extension cord.

Regarding " I did plug compressor directly into duplex receptable and still had same results. " that would suggest you have removed the cord as the primary source of the compressor problem, but it still may have contributed as an under powered electric motor runs hot, and in your case, maybe too hot.

When you say "Air does not come out of intake filter while running.??? ", that's a good thing. It suggests that the valve plate in oriented correctly.

It were my compressor, I'd next check the capacitors, and you can see how on that page on this site.

B.





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bogs down

by JC
(Northwest Ark)

I have a 60gal 3hp air compressor. Worked great til last week.

I decided to fix it up after many years of faithful service.

The 5hp motor was having a hard time so I got a new 3hp (No 5hps are available and since it was a 3hp head WhatTheHell) it worked great one time but the pressure switch was going out.

I replaced the bent and dented old copper tubes with new ones.

I replaced the switch but now Motor bogs down upon reaching 50lbs and motor STRAINS and pops the breaker. the head gets really hard to turn til it bleeds off thru valve by the pressure switch then it's ok til it gets hard to run and the motor bogs again. NOTHING was actually changed in reguard to the head. Just the switch, motor and tubes. Why is it bogging down. I'm afraid I'll fry the new motor at this rate. Why is the head acting up?? what can I do about it?
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JC, this part of your post confuses me: "I have a 60gal 3hp air compressor" and "The 5hp motor was having a hard time so I got a new 3hp"

I surmise that you are powering it with 240 VAC as a 5HP sure wouldn't run on 110.

If the original motor was a 5 HP, putting a 3HP on that pump would cause the problem. The motor bogs down because the it cannot overcome the load being developed.

If the original motor was a 3 HP, and someone put a 5 HP on it, perhaps they changed the sheaves then, and the wrong size sheave could contribute to the problem.

Remove, clean and replace the tank check valve and see if that helps.

Post an update, if you would.

Bill



Bill

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Shop Compressor not producing much air

by Leonard Ferrell
(Oklahoma City, OK)

Name plate on older air compressor

Name plate on older air compressor

Name plate on older air compressor
Old air compressor
Older shop air compressor
Name plate on older air compressor

Was given compressor during a shop clean out. Wanting to use for air tools for my shop. Can you help me with this?

Motor is operational with full RPM.

Piston on compressor seems to lag. Air pressure is very low (30 psi). Removed intake, however it appears to have very low suction. Removed exhaust, it appears to have very low CFM. What do? Please reply - Thank you!
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Well, to start with, if it is lubed, make sure that the sump has clean oil in it.

Then, see the troubleshooting page for a link to pages about why air compressor run but don't build pressure. There are some things to check there.

Your comment about low intake and pressure suggests that you'll possibly need a valve kit and quite likely gaskets too.

See the page, then add a comment here with specifics so that folks can help.

Cheers,

Bill

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