Water leaks through pump head when power is off?

[Sequoia]

I've owned my wash for 10 years now so I suppose it's time for a new problem to crop up.

The Bay 2 wand was constantly dripping water. After shutting off all sources of water supply I determined it must be leaking past the pump head when power was off. This is a CAT 340 pump. I replaced the valves with no change.

I swapped pump heads and the problem stopped. Oddly, twice around this same time I wound up with the wand tip in Bay 2 being "fouled." The second time I took the tip off and dug out a piece of metal that was lodged in the tip from the inside. It was disrupting the high pressure spray. Once I removed the metal piece the bay worked fine again. I was guessing that maybe something inside the head had broken apart? But I couldn't find anything based on a visual inspection, at least so far.

Thirty days later, the EXACT same thing happened, but this time on Bay 1. I didn't find any metal parts in the tip, but it started leaking water past the pump head. New valves changed the rate of water dripping, sometimes more or less, but in the end only made it worse. And swapping the pump head fixed it.

Now I am stumped? Each of these CAT 340's are only a few years old. So to have two fail so closely apart is a mystery? I'm wondering if this is a normal sort of failure for the pump head? Or wondering if my water supply was contaminated? Any guesses or things to look for? Thanks ....

 

[Randy]

Duane, You’re looking in the wrong place. The valves in the head of the pump will not stop the flow of water out of the pump. Your problem is upstream of the pump. Do you have any solenoid valves upstream of the pump. If you do check that they don’t have any debris under the seat of the valve or the valve is closing properly. When I get water dripping out of the wand I know I’ve got a solenoid valve that’s leaking by. I normally open up the valve check for any debris, if there isn’t any debris inside I just replace the valve.

 

[Robert2181]

I thought that someone posted a way of putting a check valve up in the trough on the manifold to stop any siphoning.!

 

[MEP001]

The high-pressure seals could be getting weak - since they're V-seals, the pressure keeps them tight against the head and the plunger when it's pumping but it may not be tight enough to keep water from just flowing through the head.

Ideally the valves will stop flow just from the spring pressure, but it can only hold back a couple PSI. If you have a tank with a level much above the pumps, you might want to lower it. A siphon break check valve at the boom will also work.

 

[Robert2181]

I have 1 bay out 6 that drips all the time. And yes my tanks are above the pumps.

 

[pgrzes]

Are your tanks higher than the height of your guns?? If so you will likely get some siphoning and may need to put a vacuum break at the highest point in the system, just a t with a check valve.

 

[Robert2181]

Yes they are. The check valves just need to be teed in with the flow end going into the air!

 

[I.B. Washincars]

Yes they are. The check valves just need to be teed in with the flow end going into the air!

The flow arrow should not be pointing to atmosphere. You want air to flow in, so the directional arrow should be pointing into the plumbing. Other than that, that's all there is to it.

 

[MEP001]

You also want to use a check valve with a low cracking pressure, something you can blow through easily. Parker brass check valves won't work since they have a 5 PSI cracking pressure.

 

[Randy]

It would be nice if Duane would come back and give up a little more information. There’s so many different types of pump set ups. Does he have a full gravity system, a reduced city water pressure fed system or a combo gravity/pressure fed system. We won’t have a gravity fed system.

 

[Sequoia]

Thank you all. Sorry for the delay. We are under evacuation for a forest fire and I can't get back to the wash. Much of the fire details is at www.thepinetree.net I think my city water is plumbed direct to the CAT head but I can't get back to check it. Maybe I should focus on my insurance coverage yikes. The nearby fire is raging out of control will post when I can. Thank you all for the responses and help.

 

[Sequoia]

Well I cannot get back to the wash as roads are closed between me and it. I'm currently on the non-fire side of things

As best as I remember, my setup has a solenoid in-line with the city water supply that supplies directly to the pump head. When I get back to the wash I will check that of course. It would be a likely point of trouble if that solenoid is slightly leaking or not fully closing. But it would still be a mystery why switching pump heads would stop the dripping at the wand?

Also as best as I remember, I have a soap and a wax solenoid that opens to permit gravity flow of product into the pump. And a soap and a wax adjustable valve so I can meter how much product passes through. When I was troubleshooting the dripping at the wand, I turned off the soap valve, the wax valve, and the weep valve. The dripping continued. So, from the responses, I think Randy and MEP are both right. It must be the solenoid on the incoming city water supply, which is slightly leaking. And due to differences in the pump head, one particular head is more resistive about letting a small amount of PSI pass than the other.

When the fire gets controlled, and when I can again get back to the wash, I will get some photos to post. Presuming there is anything left to take a picture of !!!

 

[Sequoia]

I checked the wash and found I have a Erie PopTopActuator valve #AG13A020 "upstream" from the CAT pump head. As I get water leaking from wands, I'm going to try repairing or replacing one of these in the future instead of messing around with the pump head itself.