air compressor sometimes stalls when it kicks in at 95psi

[chewy7]

So i have an older blue rol air fc2002 2hp twin stack compressor with the mk246 motor/pump. Similar to this https://www.amazon.com/dp/B000PDOOA4/?tag=atomicindus08-20 that starts up fine from zero pressure. I already know the check valve is bad and also leaks so i have one of those ordered. It kicks out fine at 120-125 psi, then leaks obviously. But when it kicks back in at the lower pressure it stalls/stops, then the on board overload/circuit breaker trips. I try to restart start it but it doesnt go till pressure dips lower to like 30-50 psi or so.
You see it sat for a while because of the bad check valve. So i tore into it to free the piston with the head off to free it up initially. then i found the middle thin gasket in between the reeds looked shot where it disintegrated a little bit . I ordered that also with the valve everything else seams to work on it so far.
So would that check valve or that thin gasket in between the reeds be causing that much of problem in that type of compressor? I could try uploading a video of it running to you tube or something to show you guys.

 

[jallyn]

Could be a capacitor getting weak.

Or, if this motor has a centrifugal switch, could be contacts on the centrifugal switch need cleaned (or centrifugal switch needs replaced).

 

[The Cobbler]

unloader valve not releasing head pressure perhaps

 

[mbshop]

I'm not familiar with that but oddly I found that loose belts will stall motors. My comp had a start up issue and started to dig in untill I touched the belts and found them loose. Tightened them up and all was well.
no idea why.

 

[Olafur]

It can't start against the pressure. It's not supposed to thats what the unloader is for. And the check valve is part of that system.

Replace the check valve and take it from there...

 

[larry_g]

A couple of things could be happening. Caps as mentioned above, or asyou said the check valve. The check valve prevents tank pressure from flowing back and pressurizing the cylinder (s). There is also a unloader that drains the air from the cylinder s to the check valve. That is the hiss you hear at cutoff. If the check valve is bad then you should hear it leaking from the unloader. If your unloader is not working then you may not have enough HP to start against the back pressure.

Run the compressor to cutoff. Then loosen the discharge pipe from the pump and see if it is leaking air. If it is then your trying to start against head pressure. Replace the check and see what happens.

lg
no neat sig line

 

[OccupantRJ]

I'm not familiar with that but oddly I found that loose belts will stall motors. My comp had a start up issue and started to dig in untill I touched the belts and found them loose. Tightened them up and all was well.
no idea why.

True info from my experience as well.

 

[chewy7]

yes if the check valve doesnt do it it could be the capacitor also. I have replaced capacitors on our farms well pumps before

 

[chewy7]

I'm not familiar with that but oddly I found that loose belts will stall motors. My comp had a start up issue and started to dig in untill I touched the belts and found them loose. Tightened them up and all was well.
no idea why.

True info from my experience as well.

lol it is direct drive. no belts

 

[bubinga]

+ 1 on the check valve, and go from there.

 

[chewy7]

and hopefully i dont have to put in a ps2020rv relief valve too lol. The motor does start up and run when starting from zero pressure every single time

 

[bubinga]

I had a small compressor was doing the very same thing.
turn it on at 0 pressure, built till 135.
Bleed off to 90 PSI, tried to start blew house breaker.
Pulled blow off valve, release pressure to 0, started right up, built till 135, bleed till 90, tries to start, blew house breaker, and so on and so forth.
Replacing, well in my case repairing the check valve, fixed it right up.

 

[bubinga]

lol it is direct drive. no belts

Well, not the belts too loose in your case,,,,,,,,,,,,,,

 

[bubinga]

say Chew, whats wrong with the Check valve.
In my case, the spring was broke, and the internal snap-ring was broken.
I had an assortment of springs, and had to get a new snap ring,
just cleaned everything up with sand paper and brake klean,
and Bob was my uncle.

 

[chewy7]

that little rubber or plastic disk was cracked/falling apart inside. the spring was still ok but i just ordered a whole new valve assembly . So that's why it didn't seal. I could of just gotten the disk but for a couple dollars more i got a whole new valve.

 

[chewy7]

I had a small compressor was doing the very same thing.
turn it on at 0 pressure, built till 135.
Bleed off to 90 PSI, tried to start blew house breaker.
Pulled blow off valve, release pressure to 0, started right up, built till 135, bleed till 90, tries to start, blew house breaker, and so on and so forth.
Replacing, well in my case repairing the check valve, fixed it right up.

mine didnt blow the 20 amp shop breaker but the breaker on the compressor would trip after a couple seconds of stalling instead which i would think is a good thing

 

[chewy7]

i would like to use it as a back up air compressor for the parlor which requires air power pressure 12 hours a day. in case the main 30 gallon rolair air compressor has a problem. plus its nice to have a portable air supply around the farm

 

[bubinga]

that little rubber or plastic disk was cracked/falling apart inside. the spring was still ok but i just ordered a whole new valve assembly . So that's why it didn't seal. I could of just gotten the disk but for a couple dollars more i got a whole new valve.

Yeah, I think three only about 10-15 dollars.
Well, let us know if that fixes it please.


Sent from my MotoG3 using Tapatalk

 

[chewy7]

well i got the 11 dollar part and a new thin aluminum top end gasket for 4-6 dollars, and it did the trick.I also changed the oil out to dewalt synthetic air compressor oil in the pump. The air compressor works like it should. I had too re dope the fitting that i threaded in the tank to keep the leakage to a minimum.

 

[bubinga]

Good to hear.
good job!

 

[chewy7]

It does leak down after a day or two of sitting it works better when the compressor kicks in