Dayton Speedaire - Unloader Valve Stuck - Help

[vervoort]

Hi Guys,
First post...I need help with an air compressor.
I have a Dayton Speedaire Compressor 1Z721C.
It was bought in the late 70's. I inherited it about 8 years back.
Nice sturdy machine, always worked well. Had to disassemble to move it a year back.

My problem.
Recently reassembled the entire compressor after a move. Everything went together fine... wired up and proceeded to fire it up. Starts fine, everything cool.
When it is charging the tank (1st time) chugs away and fills the tank. When gets to full pressure, it stops as it should. The unloader valve pops, but won't reseat, causing it to cycle endlessly while it blows off air. If I power it down, the tank drains of all air completely and the valve does not close.
Upon restart, it's still open. The valve seems to be stuck open.

So far, I have replaced the Unloader Valve Assy with new parts from Grainger.
Still, no luck. I don't see any adjustments for the unloader.

The only reference material I have is a parts diagram with an exploded diagrams for the unit. The pump is a Champion R15B.

Can anyone offer any advice? At my wits end....
I'm sure its something simple, but I'm missing it.

Thanks.
John in NJ

 

[PAToyota]

Hard to say without seeing it, but are you sure you have it in the right way? When it reaches pressure, it is supposed to unload the pressure from the compressor pump. Sort of sounds like it is set to unload the air from the tank...

 

[vervoort]

I'm pretty sure its together right.
I put it back together exactly as it came out.
The parts I replaced looked fine...
I'll double check it though. It charged up fine the first time it ran after I replaced the valve, but once it pops the first time, it doesn't seem to want to reseat itself.
Thanks
-JV

 

[Major Ramifications]

Sounds like the check valve is leaking internally. This is what separates the air in the tank from the unloader valve. If it is leaking, the unloader will empty the tank when it is shut off. Also, it will make it very difficult (or impossible) for the pump to fill the tank. If you can, disassemble, clean and inspect the check valve. You can get a new one from Grainger, even if you have to rig up something to make it work.

 

[PAToyota]

MajorRam's suggestion sounds on the right track... The unloader valve is supposed to release all pressure - but just the pressure from the compressor side. An inoperative check valve would allow it to release all the tank pressure as well.

 

[Charles (in GA)]

Indeed, the check valve allows air into the tank, but when the unloader dumps the head pressure and the pressure in the line to the tank, the check valve is supposed to stop the air in the tank from exhausting backwards thru the unloader. Sounds like this is the problem, exactly as MajorRam suggested.

Charles

 

[MXtras]

Yup. Check the check. The unloader is doing it's one and only job.

Scott

 

[vervoort]

Gentlemen,
Thanks for all your replies.
I appreciate your comments and insight.
I will take a look at this over the coming weekend and report back.
Regards.
-John

 

[vervoort]

Major Ramifications, PAToyota, Charles & Scott,

I removed the check valve as you said and sure enough...it's badly rusted and pitted. I cleaned it up enough to reassemble and test, lo and behold, my problem is solved. It still leaks by just a bit, because it was badly pitted but I'll order a new valve tomorrow from Grainger. It proves out.
I can't thank you guys enough. This has been troubling me for some time...

Fantastic!
-John in NJ

 

[PAToyota]

Glad to help out!

 

[Mandres]

Hey John,

can you tell me where the check valve was installed on your unit? I think I have a similar problem with my old Speedaire.

Thanks

 

[MXtras]

I have never seen it located anywhere but right at the tank where the pipe enters the tank. It should have a small tube attached to it but not always.

Scott

 

[vervoort]

Yes, Scott is right.
It is the last fitting into the tank itself, on the output line of the compressor.
The valve actually extends into the tank.
-John

 

[estcstm3]

Yes, Scott is right.
It is the last fitting into the tank itself, on the output line of the compressor.
The valve actually extends into the tank.
-John

Sorry to drudge up an old topic, but i have an older speedaire and I believe I have a bad check valve. Air is leaking from the pressure switch case, therefore air is coming from tank.

Did you have a hose that went from your check valve to the pressure switch as an unloader? I dont believe I have an unloader. Here is the only convient pic I have of my compressor.

Do I have to have hose to the hole in the check valve? What happens if I dont plug it?

 

[BPMaint]

We have Dayton pump 5F2353.
Lately it's been burning out motors.
We can't find a relief valve in the supply line at the tank, there is and never was a relief line to the pressure switch. Can't find any way that pressure is releasing. Nothing has been changed recently except the motor.

 

[454ragtop]

Pretty sure the check valve being referred to is known as a Load Genie. Looks like a common hex head fitting where the supply tube from the compressor head enters the tank. Threads right into the tank.
HTH, Jim

 

[redmondjp]

We have Dayton pump 5F2353.
Lately it's been burning out motors.
We can't find a relief valve in the supply line at the tank, there is and never was a relief line to the pressure switch. Can't find any way that pressure is releasing. Nothing has been changed recently except the motor.

On some lower-cost (typically smaller) compressors, an unloader valve was not used at all. Instead, there was a small orifice on the upstream side of the check valve that served to relieve the pressure in the line between the pump and the tank. Sure, the orifice leaked a tiny amount of air during operation, but not enough to affect the performance of the unit.

So on yours, listen for pressure relieving when the motor is turned off. If you don't hear anything, then you have a problem. Going from memory, I'm going to say that the orifice size is approximately 0.015".

 

[WoodenDisasterMaster]

It’s been about 10 years so this probably needs to be addressed AGAIN. On my speedair , the genie valve is in BETWEEN the pump and pressure switch, otherwise the genie valve depressurizes the pressure switch causing it to cycle even if the tank is full. Or am I mistaken? I’m troubleshooting my own compressor at the moment, it occasionally won’t cycle on, I think this valve is bad and it trying to cycle on at 95 psi on the exhaust side, and keeps popping the breaker…. That’s what I THINK is happening. I’m probably wrong, I usually am. Any insight greatly appreciated!