Pump motor runs but no pressure

[stampedecarwash]

Hello one of my pumps started acting strange. Sometimes the pressure goes almost to zero but i see that the motor works and the belt turns so it must be turning the pistons inside the pump. But then randomly it goes back to the 1200 psi as it supposed to be at. Is my high pressure valves bad?

 

[stampedecarwash]

Update: Changed all the valves and noticed the washer on one of the low pressure valves was gone... hope this helps the problem...

 

[I.B. Washincars]

It will probably help for a little while. Most likely, the missing o-ring has caused the head to wash out. Did you check it for washout before you put new parts in it?

 

[stampedecarwash]

Thanks, I did check it and noticed some residual from the o-ring so removed it. But I don't quite know what washout means. I didn't notice any grooves or something like that at the end where the valve sits when I looked with a flashlight. Also noticed the pump pressured increased by almost 100 psi when changed the valves. What's I'm missing why t does it randomly.

 

[I.B. Washincars]

There's a sticky thread dedicated to washed out heads. I'm not sure how many pictures remain after photobucket gave us moochers the boot, but hopefully there's enough there to help you out.

 

[stampedecarwash]

thanks found it in below link, no it for sure didn't look like this ...
http://www.autocareforum.com/showthread.php?10394-head-washout&highlight=washed+head

 

[MEP001]

You most likely have a leak somewhere allowing air to get into the pump. You might also have air from a low-pressure system pushing its way down the hose and through the pump, possibly from a different bay.

 

[Main Street Carwash]

May be a bad unloader/regulator. Intermittent makes me want to check that first.

 

[MEP001]

In my experience, a bag regulator or unloader won't cause intermittent problems like that.

 

[Main Street Carwash]

When the pressure drops to almost zero, is the pump pulsing?

 

[stampedecarwash]

No when the pressure drops to zero it stays... and then all of sudden it starts and goes all the way to 1200psi, as if the belt is cut for few seconds and then its back on... its either totally dead or 1200 psi, but when it comes back from 1200 psi to zero it does the pulsing...anyways since I changed all the valves no issues so far...

When the pressure drops to almost zero, is the pump pulsing?

 

[stampedecarwash]

You most likely have a leak somewhere allowing air to get into the pump. You might also have air from a low-pressure system pushing its way down the hose and through the pump, possibly from a different bay.

in a pump that's already working? Rinse has no issues..when we choose hp soap and wax (which comes from hot water tank), we see this issue.. so we thought there is too much turbulence in the hot water tank and air gets into the pump through that..but not sure why all of sudden we get too much turbulence...

 

[MEP001]

If it works fine on rinse then it's definitely pulling air in through a leak. Either the low pressure seals in the pump are bad or there's a fitting somewhere that needs to be replaced.

 

[stampedecarwash]

If it works fine on rinse then it's definitely pulling air in through a leak. Either the low pressure seals in the pump are bad or there's a fitting somewhere that needs to be replaced.

Correct, I did change all the valves, specially one of the low pressure valves was missing o-ring. so far no issues...Rinse is cold and it has city water pressure behind it... but HP soap and wax come from hot water tank which is only gravity pressure... so I think the problem was the low pressure valves...

 

[stampedecarwash]

Damn it ... it happened again... how air possibly can get in to the high pressure hose? Also shouldnt i notice some bubbles in the hot water tank if air comes back to the hp line and then back to the tank? Not sure if this is related, the ball valve and check valve under the hotwater tank which from there a hose feeds to the pump inlet, makes this clicking noise sometimes. Is it posibble a ball or check valve goes bad and stops the flow???

 

[2Biz]

I'd replace the Cv from the hot water tank to the pump. Sounds like its stuck closed. When you change it, it would be a good time to check the ball valve if its between the tank and Cv...Those are two items you can eliminate pretty quickly.

Its also possible you are getting turbulence in the tank and not seeing it when it happens. If the pump sucks air, the Cv will close and the pump will not create enough vacuum to open it. Do you have an inverted "Tee" on the float valve? This will keep air out of the water and keep turbulence to a minimum. Once city pressure rinse is selected, it starts the cycle all over again.

I wouldn't rule out an intermittent issue with the float valve. What float valve do you have in the hot water tank?

 

[stampedecarwash]

There is a long hose from the float valve going to almost bottom of the tank so making sure no air is introduced... but if the CV gets stock all of a sudden, then how come the rinse is ok? I do realize that the rinse is from city water but it also gets some hot water from the hot water tank, that's why the pump starts choking when you start closing the ball valve coming from the hot water tank while on rinse.

 

[MEP001]

Switch out the hose to a piece of pipe, have it only go down half to 2/3rds of the way, and put a tee on the end so the water comes out the sides to make sure the pick-up at the bottom of the tank has no chance of picking up air.

If closing the hot water on rinse makes the pump starve, the solenoid is either not working or it's not opening all the way, but it's still sending pressurized water to the pump. That goes back yet again to a leak that's allowing air to the pump.

 

[2Biz]

There is a long hose from the float valve going to almost bottom of the tank so making sure no air is introduced... but if the CV gets stock all of a sudden, then how come the rinse is ok? I do realize that the rinse is from city water but it also gets some hot water from the hot water tank, that's why the pump starts choking when you start closing the ball valve coming from the hot water tank while on rinse.

Are you sure rinse is ok? Have you checked water temp in the bay when rinse is selected. You sure its not hot water? Even if the cold water solenoid fails closed, you still should be drawing from the hot water tank. Like MEP says, it has to be getting air from somewhere. Put a TEE on the float exit and see if that helps. I would also check the cold water solenoid to make sure its working properly.

BTW, what kind of float valve are you using?

Is there a filter screen in the bottom of the hot water tank. Have you checked to make sure its clear?

 

[stampedecarwash]

Yes I'm 100% sure rinse is ok, and have gone back and forth between rinse and wax/hp soap, and rinse is good but hot water items no.
I have closed the ball valve half way to balance out any possible turbulence coming from the hot water tank and seems to be workign fine, SO FAR.
here is the float valve I have. in the pic doesn't show a foot of hose coming
https://www.dultmeier.com/products/0.689.1011.3942/6374