Foaming wax in spot-free rinse??

[GregF]

Scratching our heads here... Does anybody know how our foaming wax could possibly be getting into our spot-free rinse tank and/or how the spot-free application could start out "spot-free" on our Laser 4000's spot-free rinse cycle, but be spitting out foaming wax by the time it gets to the right rear quarter panel?

Already replaced o-rings in the check valves above the automatic bay. Attendant said he definitely noticed a pinkish hue in the spot-free tank earlier in the week, so he drained the tank. Tank is currently very clear with "a little bit of foam/bubbles" on the surface of the water.

Could something possibly "backfeed" into the spot-free tank???

Is there any place besides the manifold above the bay where wax could be getting mixed into the spot-free water?

 

[MEP001]

It sounds like a check valve issue - yes, you can definitely get backflow into the tank. It sounds like there's high-pressure water feeding too. You may be mostly spot-free rinsing with water backed up into the hose to the tank, then you get a blast of the foaming wax that backed up before.

 

[GregF]

Any idea which check valve might be the culprit?

 

[MEP001]

There's likely only one check valve that stops the other stuff from getting back to the spot-free tank.

 

[madscientist]

mep1 is right, as usual. find the hose that delivers the spot free water up to the manifold and out to the bay. there is a check valve on it as it joins the manifold. that's the likely culprit, not check valve on the wax hose.

 

[lag]

Do you use the tank above the pumps to store the spot free water? And do you use the same water for your LP functions? if the answer is no then the following does not apply.

there is a small check valve at the bottom of the manifold for the solenoid tree that also could be the problem. I have also seen a solenoid stuck open ,and a bad check valve on the bottom of the solenoid tree allow chemical back to the tank above the pumps.

 

[GregF]

That WAS the culprit. My attendant replaced slightly worn o-rings on two of the check valves above the bay and was "positive" that he had eliminated the check valves above the bay as a potential problem. When I went to the site to help him out, he started showing me the battery of tests that he'd been performing, the first of which was to turn on the foaming wax output. As soon as he turned it on, the spot-free tank started bubbling & churning so we knew it had to be a check valve. It turned out that he'd had a little bit of a brain fart when he thought that the male/male check valve on the spot-free line was just "some sort of coupling." ...The other check valves that he'd been used to working with were f/f. So we took that check valve off and found a nice-sized shard of plastic jamming it up.