Unloader valve won't release pressure.

[Johnny]

Old PowerClean Freedom 47 was working fine except unloader valve was chattering a little, so I replaced it. Started pump and pressure jumped to 1200 psi with a slight clockwise twist of the handle and pressure wouldn't drop with a counter-clockwise twist. Adjusted the tension on the valve, started pump, worked fine until I noticed the bleeder valve was open a little. Closed the bleeder, and pressure jumped to 1200 and kept climbing until I shut pump off. Installed another new unloader valve; same symptoms. Replaced Cat 3CP1120 seals; same symptoms.

Strange that TM was operating fine except for a little chattering before I replaced the unloader valve. I replaced the unloader two or three times over the years with no problem.

All ideas welcome. (Pump valves?)

Much obliged.

 

[Erik_CatPumps]

I would next look at the unloader bypass hose. If you have any debris, it maybe not removing the pressure in the system fast enough. Could have caused the chattering too.
Pump valves should be fine.

 

[Johnny]

I would next look at the unloader bypass hose. If you have any debris, it maybe not removing the pressure in the system fast enough. Could have caused the chattering too.
Pump valves should be fine.

Thanks, Eric. I wondered about that, so I connected a garden hose to the bypass outlet and let it run onto the ground, with no change. System bypasses to the blower heat exchanger, and empties into the mix tank. Doesn't seem to be any obstruction.

 

[Erik_CatPumps]

Thanks, Eric. I wondered about that, so I connected a garden hose to the bypass outlet and let it run onto the ground, with no change. System bypasses to the blower heat exchanger, and empties into the mix tank. Doesn't seem to be any obstruction.

Hmm, not familiar with the Powerclean Freedom set ups. Would think something is happening after the unloader to not allow it allow it to bypass as it should.

Welcome to call and discuss if that helps. 763-780-5440

 

[Jim Martin]

did you remove the check valve...???

 

[Johnny]

did you remove the check valve...???View attachment 74969

Have not removed check valve. I'll try that. Thanks.

 

[Johnny]

Have not removed check valve. I'll try that. Thanks.

That did it! Thanks, Jim!!!

Eric at Cat Pump suspected the check valve. Thanks, Eric!!!

 

[Jim Martin]

anytime.......

 

[KevinL]

So you just take out the check valve and leave it out? What does it do?

 

[Nate The Great]

JM to the rescue!

 

[Erik_CatPumps]

See video below, check valve is kinda what makes it an unloader.