Air Compressor - Air too hot!

MrB

MrB

Joined
Oct 27, 2012
Messages
65
Location
Columbia, Illinois
Bike
2013 GL1800 F6B
Air Compressor - Air too hot! **FIXED!**

My old Campbell Hausfeld ~20 gallon horizontal single-stage compressor has been putting out air that is hotter than normal.
I've got an on/off cycle activated condensation release valve that hooks in to the pressure relief hose that comes out of the high pressure line. Everything was fine for many years then suddenly it started melting the line where they "T".
I've regularly changed the oil, I don't use it a whole lot, maybe a couple times during the week during summer, less so other seasons.
The OEM tubing has not melted through, but it also gets much hotter than it used to.
Steps I've taken:
Changed oil. (it doesn't leak oil)
Checked reed valve. Clean, seats well. When it was off I peeked into the cylinder, the piston looked clean, no oil in there.
Checked ball check valve at top of tank. Looks and seems to function properly. Will verify by running some air in and checking for leak.

To clarify, this has an AC motor connected to the pump via a belt. The pulley has an integrated cooling fan for the pump. There is a plastic safety guard around the belt/pulley assembly which is not clogged or misaligned.
I'm assuming this just uses splash oil from the crankshaft to lubricate everything.

Don't have money for a decent new one, I got a little HF noisemaker to get me by, but I miss my old compressor. Hardly worthy of a real shop, but it is (or was) head and shoulders above the HF tiny screaming devil. The Campbell fills up quick and supplies enough volume of air for my needs.

I could always take the condensation valve off and go old school with a standard petcock and OEM tubing, but it's SOOOO hard to get to and there's still the matter of the compressor running hotter than normal. It will even melt the non-OEM hose in the dead of winter.

Any thoughts?

Thanks,
Robert
 
Last edited:
Did you clean the air filter? A dirty one can cause it to run hot.
 
Doh! Forgot to post that part, air filter is clean. There's not much of one and it's easy to get to.
There's not much else to this machine! Rings could be gunked up and unable to compress?
A rebuild wouldn't be too difficult if I could get the parts, if indeed the excess heat was being generated by the rings.
I'm a cheap old fart when it comes to some stuff, was hoping this compressor would outlive me.
 
It could be melting if the hose isn't compatable with oil. I've seen many hoses blow out, due to softening when exposed to oil. I would try a different hose. Do you have any way to measure how hot it's getting? The last ones that I fooled with had discharge temps of 180F, but they were 200 HP. The type of oil can affect the operation also.

John
 
Compressing air generates heat ... it can't be avoided. My speculation is that it is compressing more air now (more heat is generated) OR the tubing has degraded due to oils and/or UV light, and is now failing.
 
Did you check your inlet air filter? I'm not sure if that might cause more heating on air compression (think diesel engine), but woth a look (you didn't mention checking that). They do collect gunk and dirt over time. Generally, more heat equals higher compression in the pump cylinder(s). Is this a 2-stage pump? Check the transfer from low pressure piston (big one) to the high pressure cylinder (small one). Could be a blockage creating higher compression in the LP cylinder. If an outlet reed valve on either cylinder was seeping before, but has now sealed up, that would create higher compression. I have a 35 gal Huskey compressor (from Home Depot) - about 14 yrs old. All the piping from compressor outlet to tank is 3/8" copper. All of the control stuff is on a tee at the tank outlet. That copper compressor outlet line gets very hot very fast, but that is normal. If you have stuff piped into the compressor outlet, I'd move it to the tank outlet. Even if you had bad compressor bearings, the compressor might get hotter, but I doubt the outlet air would go up in temperature very much.

Hope that helps.
 
Empty the tank and remove the pressure pipe that connects the compressor pump to the tank. Examine for restrictions. Over time especially on old compressors the small amount of pump oil that gets into the pipe can carbonize and cause a restriction. That will cause the compressor to run longer and create more heat trying to compress the air through the restriction. Note the pipe isn't the only place this can happen. Could be on the outlet of the cylinder head or the inlet of the tank as well. Just a thought
 
Is amperage draw up on the motor?

I'd say remove the rubber/plastic and re-pipe with copper.
 
I'm gonna tear the whole thing apart, make sure everything's clean and in order. If I can't solve this problem I'll ditch the automatic drain and run it stock.
I've gone through a lot of tubing at the "T", one cycle of bringing it up to pressure will melt it.
Have always used ND 30 weight, given it's age and the issue I'm considering putting some leftover synthetic in it unless someone says "NO!".
When purchased it was already a few years old, and that was ~18 years ago.
Life requires us to pony up a little cash now and then, I'll buy a nice vertical tank model if need be. Hopefully all the new compressors don't sound like the tiny (but loud) HF compressor!
Thanks for all the input, I'll post back with any solutions or failures.
 
I use a 30 year old compressor at home. Love it!

Noise is directly related to rpm, motor drive and compression type. But also most noise is generated by the inlet air. Pipe in a remote and muffled intake and you would be surprised how quiet a compressor really is on the compression side.

You are correct. Do not use multi-viscosity oil. Preferably not even SAE oil. Just find a straight weight oil. The SAE oils have detergents and other chemicals designed for internal combustion engines.
 
Have you recently turned up the air pressure. Higher Pressure = Higher Temperatures
Try to set the regulator to the pressure you need, not to the maximum pressure that the compressor can put out.
 
Al Gully said:
Have you recently turned up the air pressure. Higher Pressure = Higher Temperatures
Try to set the regulator to the pressure you need, not to the maximum pressure that the compressor can put out.
Click to expand...

Adjusting the output regulator will have no effect on the cut-in/cut-out pressure that the pump will switch on and off with. Those are controlled by the pressure switch and on most small consumer models is not accessible or adjustable.

On models where it is accessible, be very cautious of making adjustments. A little turn goes a long way.
 
I used to sell and service all kinds of compressors, including larger Ingersoll Rands. Your symptoms are unusual, and I have to ask if the compressor is running longer to pump up than it was before. It takes time to build up to melting heat, and even a tiny single piston pump should fill a 20 gallon in a few minutes.
 
At that age possible that the valve plates weakened (or suffered micro-cracks), causing them to leak back, thus increasing the discharge temperature?
 
Svrdhd said:
I used to sell and service all kinds of compressors, including larger Ingersoll Rands. Your symptoms are unusual, and I have to ask if the compressor is running longer to pump up than it was before. It takes time to build up to melting heat, and even a tiny single piston pump should fill a 20 gallon in a few minutes.
Click to expand...

When I return today I'll run it without the auto discharge tubing in the circuit and see how long a complete cycle from 0PSI to shutoff takes.
Wanted to clarify: the OEM tubing does not melt. The aftermarket accessory tubing did not melt for well over a decade, then started melting. The OEM is close to melting because this is crazy hot.
 
MrB said:
The aftermarket accessory tubing did not melt for well over a decade, then started melting. The OEM is close to melting because this is crazy hot.
Click to expand...
Indicating that something has changed, causing excessive discharge temps; either the thing is starving at the intake, or an unintended internal bypass/leakage is present...
 
ST1100Y said:
Indicating that something has changed, causing excessive discharge temps; either the thing is starving at the intake, or an unintended internal bypass/leakage is present...
Click to expand...
Yes! While looking at the "T" it occurred to me that air shouldn't be flowing through the side that goes to the water release valve. Just like in a plumbing system, the whole system is pressurized but you can't get hot water at tap A by running hot water to tap B.
There shouldn't be air flowing through that piece of hose. The side that goes to the regulator does not get hot enough to melt but the side that goes to the release valve does.
The release valve is faulty, allowing air into the tank through the drain hole constantly.
I will replace or remove the faulty valve.
As I stated earlier, the compressor works when it is run with the stock setup.
I got over a decade of use out of the automatic condensation release valve, not bad for $10. If HF doesn't sell them anymore I'm sure I can find one somewhere.
With back and knee issues I try to minimize my time down low on concrete.
Thanks to all for the help, maybe this little compressor will outlive me!
Robert

edit: looks like it's still available. I'll know when it's failing next time!

A trip to HF and $10 later it's working perfectly. The auto drain valve was allowing air to pass AND was leaking. The leak only occurred while it was running so I didn't hear it. Fills up MUCH faster now and it drains the water after each fill cycle. Thanks again!
 
Last edited:
MrB said:
As I stated earlier, the compressor works when it is run with the stock setup.
Click to expand...
uoops, that did pass by me...
But good that you've circled down the culprit, I doubt that any 'new' compressor will provide the quality to the touch and lifespan...
 
ST1100Y said:
uoops, that did pass by me...
Click to expand...
Only because you'd have to really read between the lines to figure that out, should've made it clearer.
Been on cloud 9 all day, it doesn't take much to cheer me up!
Didn't want to try to seat new tires with the tiny HF compressor, and it runs constantly even when doing something simple like filling tires.
Mmmmmm, the old one sounds so good.
Next: new tires!
 
I also don't like those small, high-rpm compressors, they run so high discharge temps, that you'll always have a pretty 'wet' air in the tank, always requiring/filing the additional water separator at the pressure regulator... (and still too wet to use a paint-gun...)
Them older, low-rpm run with lower temps, thus less condensate in the tank, and the air delivered is way dryer... which is also better on them power tools...
 
You must log in or register to reply here.
Back
Top Bottom