Low Pressure Problem

[MichaelGlenn]

I'm pulling my hair out... I swear this has to be something really simple:

I've just pulled all new hose at my wash in the process of rehabbing equipment. New Kip Solenoids/manifolds, new flojets, yada yada yada... I have ONE BAY that Tire Cleaner will not flow AFTER running high pressure. I initially assumed a bad check valve -I replaced check valve (on liquid) twice and I still have the same issue AFTER running high pressure. I've checked voltage, I really don't think it's my rotary switch, etc.

Important piece of info... when I turn switch to Tire Cleaner, I can feel solenoids energize so I know they have current but FLOJET will only begin pumping after I either increase pressure on liquid or reduce pressure on air.

So it appears to me that the HIGH PRESSURE is somehow air locking the FLOJET? Would this make sense even after changing check valve twice? Again Tire Cleaner is working just fine in all the other bays, just this one.

Help Help Help.

Michael

 

[ken-pro]

What are your liquid and air pressures?

Liquid pressure should be 60-90 PSI for Tire Clean. Air pressure should be 20-30 PSI LESS than the liquid pressure. If the pressures are to close together, the Flojet pump will lock up.

 

[MichaelGlenn]

Thanks Kevin. I want to say that I tried increasing the pressure accordingly but I will do so again to see if it makes a difference. As I mentioned, this is only happening in ONE bay... wouldn't the pressure issue be present in ALL the bays? By the way, I'm using non-metering blocks.

 

[MEP001]

Look at the solenoid on the tire cleaner - it sounds like the MOPD rating is lower than the system pressure.

If the high pressure was causing the problem, first thing you'd notice is the gauge on the tire cleaner would be pegged, second it would affect all the bays and not just one.

 

[Earl Weiss]

All bays have variations. Hose run length, nozzle wear etc. Different solenoids can have variations and debris could be partialy clooging a line so that can be a reson one is affected and not others.. I would set the air at 10 PSI and see what happpens. If that solved the lockup issue I would then gradualy increase air pressure if needed.

 

[MichaelGlenn]

MEP001: So I will try replacing the solenoid on the liquid side. As you mentioned regarding High Pressure... this would only be a problem if in fact the check valve is bad.. right? And if that was the case, it would affect ALL the bays? I do believe I had this same scenario happen last year at my other wash where one check valve on TC was going bad and was air locking the entire TC manifold which affected ALL the bays.

So I would think and if I'm understanding correctly, it's unlikely that the check valve is the problem and more likely that I need to swap solenoids and also check the hose feeding this bay?

Look at the solenoid on the tire cleaner - it sounds like the MOPD rating is lower than the system pressure.

If the high pressure was causing the problem, first thing you'd notice is the gauge on the tire cleaner would be pegged, second it would affect all the bays and not just one.

 

[2Biz]

How many CV's do you have on TC? My old system had 3. One on each liquid and air and one between those 2 and the HP hose as a backup. Do you have the backup CV? If so could it be that one hanging up? It sounds to me like a CV since it is only happening in one bay. Try swapping out the CV's with a bay that works. See if the problem follows.

 

[MichaelGlenn]

2Biz: I have one check valve from FloJet>Manifold to protect FloJet, then the next check valve would be above the bay where TC hose meets manifold. That's it.

M

 

[Randy]

Have checked the voltage to the solenoid valve when it’s energized before and after you run the High pressure function. Have you disconnected the hose from the solenoid valve to see if it will pump fluid when you’re having this problem? What kind of check valves are you using? Without being there it's pretty hard to tell you what the problem is.

We only have one Flo-jet pump left and it’s on the Foam Brush system. We replaced them all on the low pressure systems with Procon pumps years ago.

 

[MEP001]

Look at the MOPD rating of the solenoid before you swap it.

 

[2Biz]

You say you pulled all new hose....What size hose did you use? If you're using 1/4" tubing, its possible you could be loosing enough pressure out to the problem bay that theres not enough pressure to crack the CV? Is the problem bay the furthest one out from the ER? You said increasing the pressure made it work?

Here is an online calculator to help you calculate pressure loss for a given ID diameter hose and length of run. The loss will be a little higher since it doesn't take into consideration head pressure lost between the pump and the cieling.

http://irrigation.wsu.edu/Content/Ca...ssure-Loss.php

1/4" poly has an ID of .17” and 3/8” poly has a .25” ID. Its amazing there is that much restriction in ¼” tubing. But there is.

 

[MEP001]

You say you pulled all new hose....What size hose did you use? If you're using 1/4" tubing, its possible you could be loosing enough pressure out to the problem bay that theres not enough pressure to crack the CV? Is the problem bay the furthest one out from the ER? You said increasing the pressure made it work?

I doubt the tubing is the issue - the longest run I've got is over 100' and there's not a major issue with pressure loss.

 

[MichaelGlenn]

UPDATE -

I swapped hoses in the mechanical room liquid and air... Tire Cleaner appears to be flowing as normal, but air is NOW restricted. So this must have something to do with the hose itself. I got the ladder and tried to follow the hose from one end to other to look for an obvious kink or restriction... I guess i'll have to pull a new hose... It's really weird I know but i'm pretty sure i've eliminated just about anything else this could possibly be.

 

[MEP001]

There might be something in the line. You could try unhooking it at the boom and running air through it first.

 

[MichaelGlenn]

Question: following up a discussion from a while back, this may be an elementary question for all the car wash veterans but.. here goes.

How do I catch a failing check valve in the equipment room without having to climb on the roof unscrew low pressure lines and run the high pressure pump? My tire cleaner manifold (liquid) is getting high pressure coming back from one of the bays, nothing has blown off, just seeing pressure gauge maxed out and i'm having to release pressure on manifold to get tire cleaner moving to bays again.

 

[Randy]

Disconnect the hoses on the manifold in the equipment room one at a time, run that bays high pressure function and see if you get any pressure back though the disconnected hose. After you figure out which one is bad climb up on the roof and replace that one.

 

[MEP001]

Do you have air running to the bay for tire cleaner, and if so does it share the check valve with the liquid?

 

[MichaelGlenn]

Do you have air running to the bay for tire cleaner, and if so does it share the check valve with the liquid?

Liquid and Air are on separate check valves overhead at bay. I did find 3 bad Parker check valves yesterday!! I mean wow, when it rains it pours! We had a cold snap here last week, down in the 20s, wondering if that was part of the problem. Whats your recommendation on a quality check valve? Parker quality issues?

 

[Randy]

Liquid and Air are on separate check valves overhead at bay. I did find 3 bad Parker check valves yesterday!! I mean wow, when it rains it pours! We had a cold snap here last week, down in the 20s, wondering if that was part of the problem. Whats your recommendation on a quality check valve? Parker quality issues?

WOW!! 3 bad check valves, your right when it rains it pours. This is the only check valve we use https://www.kleen-ritecorp.com/p-1764-fluid-controls-check-valve-14-viton-ss-hp.aspx I can't remember when we had to replace one. We've had problems with the Parker checks failing after a few years.

 

[MEP001]

Your Parker valves are probably full of crud broken loose from the lines after that freeze.

You might consider putting the air and liquid on the same check valve (Fewer valves to fail) and using a Speedaire or equivalent air regulator that will bleed off excess pressure on the outlet side. It will prevent burst lines or locked up solenoids if pressure comes back from the bay.