Help Please. Check Valves on air compressor?

[Cuerno Largo]

I have a Kobalt 80 gallon compressor that I bought new and have used for the past 5 years. Yesterday, things were running well and then a loud pop followed by many pops that sounded like they were occurring with each "pump" of the compressor. Here are some crappy cell phone pics of the compressor and the offending part....






Is this a check valve and if so, anyone have any tips on were and how to replace one? It might just be paint, but it looks to me like it might be soldered in.

Thanks for looking.

 

[jasonmt]

Interstage (low side) pressure relief valve, should be threaded in and a replacement valve should be under $20.

It is a chicken and egg question as to if the valve failed due to age and lack of maintenance OR if the first stage over-pressured and the valve operated as it was designed to though.

These style of valves usually have a ring in the spindle so you can "ease" them which is something you should do periodically to ensure that they are free to operate, you may have debris trapped in the seat causing the leakage.

Given the cost of a new valve I would just replace both the low side and high side valves to ensure that they are operational and will operate at the correct set pressure.

 

[Cuerno Largo]

OK, I replaced the check valve. I was only able to find one website that had the valve matched to the number for my model, but it does not look the same as the original. No ring as pictured below though. The safety valve on the compressor does look like the one below.

The same symptoms happen, but the previous valve was "releasing" at about 100 lbs of tank pressure and this one gets to about 150 before it "releases"(I guess that is the correct term). My compressor tank pressure is supposed to get to 175. I continued to let it run and it did eventually get there, but it just took longer.

Several questions:

1) Are these valves something that has to be replaced once it "releases" or does it just relieve the pressure and then continues to function when it needs to.

2) I am now worried there is something else going on to cause this. What do I need to look for?

The oil is not low and still looks clean in the sight window. I have not replaced it though.

The air filter is clean.

No knocking noises.

Could a loose belt do this? When I had the cage off and ran the compressor, the belt looked like it had more vibration than before and this seemed to worsen as the pressure in the tank increased further.

Thanks again.

 

[Dirtsquirt]

The pop valve isnt your problem

The pop valve is put in the intercooler between the 2 stages for for a reason. to tell you that valve failure has or is occuring.

Pulling the head and checking the exhaust valves is in order.
your failure will be there.

A piece of carbon stuck holding the valve off the seat. or a screw that is supposed to be holding the reed valve in place.
a chunk missing from y our reed... a chunk missing from your disk. fatigued and missing springs.

Any number of things could have happened. but the procedure is the same. Remove the head. fix the broken valve.

also replace that 150lb safety valve with a 100psi valve.
That cylinder shouldnt see north of 70psi under normal operation conditions. (Low Pressure) it is now pushing 150
motor failure, compressor failure etc. are in your future if y ou
do nothing

 

[Cuerno Largo]

also replace that 150lb safety valve with a 100psi valve.
That cylinder shouldnt see north of 70psi under normal operation conditions. (Low Pressure) it is now pushing 150
motor failure, compressor failure etc. are in your future if y ou
do nothing

Thanks for the info. Just what I was hoping I would not hear

I think I may not have adequately explained the safety valve I replaced. It is a 65 psi valve on the intercooler, not a 150psi. The tank pressure is what gets to 150 before this thing goes off. The manual states that the aftercooler valve is 217psi.

 

[Cuerno Largo]

Pulled the head and replaced the valves and gaskets. Fired it back up last night and problem was solved. Thanks Dirtsquirt.