the compressor is working, but there is no air coming through why ?

by thai
(england)

i leave overnight running without oil, next come in to work found it burning, dont what happen still runing but there is no air

th2i@hotmail.co.uk thank you?






Bill answers...

Hi Thai:

Whoops! That's not good.

When a reciprocating, oil lubricated compressor is run without oil in the sump, the same thing happens to it that would happen to a car engine run without oil. The engine will very quickly overheat, and some components in it will fail.

You say your compressor is running. From that I understand that the motor is running, yes? Can you hear also the typical sound that the compressor head makes when it is being driven by the motor?

If so, you may have simply burnt away the seals around the piston, and since air is bypassing the piston as it strokes, no air is compressing into the tank.

Unfortunately, it may also mean that the crankshaft for the piston itself has broken, as the piston got so hot that it expanded inside the cylinder and seized.

In this case, if the motor was powerful enough, it would have continued trying to drive the shaft, and it may have broken.

Regardless of what has been damaged, I suspect you are in for a rebuild to correct the damage caused by running the compressor without oil. Time to take it to the shop.

Cheers,

Bill

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COPELAND compressor only runs for 5 sec. at a time

by George Pierce
(Lake Elsinore, Ca.)

The air compressor will only run for 5 sec then shuts off even when first turned on.

It will then wait for several minutes then turn on again for 5 sec.

It repeats this cycle over again until there's too much pressure and the valve blows.

Then it starts over again. thanks for any help you can give. it's a 10 year old COPELAND dental air compressor. thanks alot.... George Pierce






Bill says...

Hmmmm? The valve blows. Am I correct in guessing that it's your PRV valve that blows? At what pressure does that happen?

If it is the PRV that lets go, that and the sequence events that you describe, suggest to me that you need a new pressure switch.

Change the switch out and see. That's a fairly low cost fix if it's the switch that's the problem, or even if it's not.

Cheers,

Bill

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Nov 10, 2010
Compressor start up problem - breaker pops
by: shaikh

whaile compressor start up after 3 minutes breaker tripped with ground fault indication.

_____________________-
Shaikh, you may want to re-post this comment from the Troubleshooting page, under electrical problems so that lots of folks can see it, and perhaps offer more advice for you.

If I understand correctly, your breaker has a GFI element, and the GFI is tripping?

That being the case, it would suggest to me that you have a short, and if it's within the compressor, I would start looking at the pressure switch first.

Good luck.

Bill




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Sparks flying... from what?

My proforce air compressor has always been a bit of a slow starter, especially in colder weather.

Last night was the same thing, it sounded like it was trying to start, but then some sparks came flying out and after that it was dead as a doornail.

I took the top cover off, and there is a piece that looks like it could be a fan, but it appears to be a bit melted. Is it totalled?

______________________
Bill says...

I've written quite a bit about cold weather operation of compressors on this site. Essentially, if you have an air compressor that is marginal (that is, just enough power to get it going) and you chill it down, it may not start at all.

In terms of your "sparks flying"... from what did they fly?

I can't tell you for sure if your motor or compressor pump is totalled... but it sounds like it could be a possibility.

I can't see what you are seeing ( a photo or two is always helpful ) so if you could repost here with more details, maybe between the three of us (you, me and the 10,000 + visitors a month) we can help figure it out.

Cheers,

Bill

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draper 50L 2hp compressor - Burnt oil

by Matt
(Cambs)

Hi - I have a draper 50L 2hp compressor. I have noticed that it is getting very hot and the oil is very black and smells like it is burnt.

Tried changing the oil and going again but it just blackens it and smells still.

The cooling fins on the cylinder and head will get hot enough to burn your skin if the compressor is run up from empty.

Removed the head cylinder and piston to check for damage or scoring and they are all smooth and look ok to me. The bottom end is fine too and i am at a bit of a loss as to what to check next.

Any ideas?

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Bill says...

Matt. You've pretty well covered all the diagnostics I would do.

One thought... is the motor on the Draper air compressor direct coupled? Is the motor itself getting hotter than normal. It's a bit of a stretch to think that there would be enough heat transfer to the pump to the sump to burn the oil. However, I would check anyway.

Another thought. Shut it down, drain the air, and check the CHECK VALVE going into the tank. If it's jammed the back pressure might cause your air compressor to run hotter than normal.

However, I really do think you have a metal to metal friction issue, based on the amount of heat you are referring to.

My two cents worth.

Cheers,

Bill

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