Presoak problem

[jprb]

Our presoak is failing to make it to the bay. We use a flojet pump -> checkvalve -> 4 solenoid (1 per bay) -> checkvalve @ manifold above each bay.

When the presoak fails, it fails in all bays. I checked it today, and began tracing the flow. Pump works when I removed the hose @ the pump. Presoak flows through first checkvalve before solenoids. I took hose off after solenoid, turned on the bay, and presoak flowed. After I hooked the hose back up, presoak flowed to the bay, and all others.

I'm stumped.

Thanks, in advance, for any ideas!
JPRB

 

[MEP001]

Sounds like the FloJet might be stalling. Do you have a spare to try?

 

[jprb]

MEP, I put on a new flojet (Viton) the day before. It has done this several times. Seems to work for a while, then quit, then work again for a while.

 

[Randy]

If it doing it Off and On intermittently I’d get out the volt meter the next time it doesn’t work and start checking the voltage and common on each Solenoid. It could be you’ve got low voltage, a bad ground or common.

 

[copperglobe]

Water in the air will stall the pump- even a new one. Dry the air?

 

[MEP001]

You may have a bad check valve in a bay that's allowing high pressure back through the presoak line, which will get past the solenoid and cause pressure trapped between the check valve and the solenoid - at that point there's too much pressure for the solenoids to open. What is your gauge reading?

Do you have air to the bay with the presoak? If not, add another solenoid stack and line for each bay and tee into the existing check valves. Use an air regulator like a Speedaire that will relieve excess pressure on the line. Not only will you be able to run the presoak stronger without it costing you more, the air regulator acts as a relief if a check valve fails and won't cause the whole presoak system to quit.

 

[jprb]

MEP, What you have described sounds right. I have the air guage on the flojet set around 75psi. (no other pressure gauges on the presoak) Also, we do not have air on the presoak at this location (yet). I have taken the lines off of the solenoids to see if there are any of the check valves (at the bay manifold) failed. When running high pressure, there is no water coming back in the presoak lines. I'll take them all off this week and check them, though, in case they have a "small" failure that's not letting the water free flow back.

Thanks for the suggestions!
JPRB

 

[Earl Weiss]

I think 75 PSI to the Flo Jet is too high. Do you have needle valves a t the solenoids. I thhink your pump should put out plenty at 60 PSI. I think this gives about 6 gallons pr minute, and with .05 nozzles you could have about 12 running on the one flo jet. (I think the rating is over stated and it depends on distance, but you should still get plenty of flow at 60 PSI. ) I think excess pressure for what you need shortens the pump life.

 

[MEP001]

Earl, I've always run the FloJet at 80 on the presoak, and the pump is dead-headed so it's always at pressure. They last around five years - I feel like that's plenty to expect from a $90 pump.

I do agree that 80 PSI might be too much since he doesn't have air to slow the flow of product to the bay - if he's running it strong enough to clean effectively, a lot is getting wasted.

 

[Ghetto Wash]

I've added a small hydrominder tip on the manifolds of presoak and tire cleaner to relieve pressure if a check goes bad and backs up into one of these low pressure lines. Just run the new line from the tip back to the tank. This should accomplish the same thing as MEP suggested if you don't want to add a new air manifold in parallel with the liquid. MEP's idea wouldn't work for me as I have seperate checks for air and liquid.

If the check leaks really bad it will burst a low pressure line to let you know which one is bad. I ran nylon to the bays except for the first 12" or so is poly (lower burst pressure), so when one bursts I don't have to climb on the roof to repair it, the burst is in the poly in the equipment room.

I learned this from ACF years ago and has been working fine.

 

[Randy]

I had to go out to the Army base today, same problem intermittent Presoak, they said sometimes it works and sometimes it doesn’t. It turns out they had a bad common on the presoak board, one of the employees had been messing with the system, that in its self-made matters worse. The guy who runs the car wash told me that they had been having problems with the presoak hoses blowing off the solenoid valves. The car wash had been remodeled about 2 years ago and the installer who did the work did it as cheap as he could and used the SMC check valves http://www.kleen-ritecorp.com/p-1754-smc-14-fxf-1200psi-3-psi-check-valve.aspx everyone I pulled out leaked by. I replaced them all with a Fluid controls check valve http://www.kleen-ritecorp.com/p-1764-fluid-controls-check-valve-14-viton-ss-hp.aspx problems solved.

jprb - Fiqure out your problem is yet?

 

[jprb]

I replaced all four of the check valves at the manifold at each bay. A couple of them were bad. Waiting to make sure this solves the problem. All good so far! Thanks again for the suggestions.

Randy, I have begun using the check valves you recommended. The valves I removed were a different brand. Thanks for the help.

JPRB

 

[MichaelGlenn]

jprb: I have the same low pressure tire cleaner setup you mentioned in the start of this post. (I do have air running parallel to the liquid.) I'm having the same problem with all bays not working... already replaced Flo-Jet, replaced common wire on manifold, etc... tire cleaner keeps failing...

While troubleshooting the problem i've noticed that if I turn air off to the manifolds and allow pressure to drop, when I turn air back on, bays seem to work! So frustrating. Does this sound like a bad check valve issue and similar to what you experienced?

I think the next thing to do is get on the roof and start replacing check valves.

 

[JGinther]

If the pressures or needle valves (if installed) are not set correctly, the air pressure for foaming the chemical can exceed the pump pressure causing the pump to not operate. If lowering the air pressure only (not the pump feed pressure) makes the pump start working, this is the problem... Just one more thing to check...

 

[MEP001]

It's also possible that the pressure is higher than the solenoids are able to open. Check the MOPD rating on the solenoid and make sure the pressure isn't higher than that.

 

[jprb]

After changing all four (one to each bay) check valves at the manifold above each bay, the system has been working properly (for almost a year now!) I assume the back pressure from the leaking check valves was locking up the flojet pump.

 

[MichaelGlenn]

Got on the roof today, found one check valve that sure enough was failing... hope this is my fix! Thanks.

 

[MichaelGlenn]

update: one week later, tire cleaner still working... seems this was the answer!