HP soap / Hp wax getting into R/O

[JustClean]

Hi guys,
This is my problem:
I have Mark7 self serve equipment. When switching from either HP soap or HP wax to low pressure RO water, it either takes at least a minute for clean water to come out of the gun (closest bay) or even no clean water at all (farthest bay). It never has done this before. Would you have any ideas?

 

[MEP001]

Does your system have a separate pump for the spot free to the bays? If so, one of the check valves on the spot free lines to the bays has failed.

 

[JustClean]

Hi Mep,
yes, got a separate pump. Thanks for the input. A technician was telling me the same so I'll come back when it's working but I need to shut down all bays for it.

So it means the soap can go through the failed check valve and ends up in the R/O line for all the bays?

 

[MEP001]

Yes, it's not uncommon to have happen.

 

[JustClean]

But that would mean the check valve AND the R/O valve must have failed for the soap to get into the line?

 

[MEP001]

Solenoids don't stop flow in reverse direction, so if you aren't seeing spot free running in bays it shouldn't be while another is running then your RO valves are ok.

 

[JustClean]

Okay, I've done more testing.
1.
Possible reason: Check valve of R/O broken, HP soap or HP wax being pushed in
towards the R/O manifold and mixed up.

Test: Removed all R/O hoses at solenoid & checked for any soap/wax coming back from the pump.

Result: Bay 1 few drops of water came back out of the hose. Rest fine. Since I didn't have a new check valve I turned off a valve before the R/O solenoid to prevent contamination. Checked again. Soap is still coming out. No change. So it can't be the check valve.

2.
Possible reason:
ALL HP Soap & HP wax solenoids blocked due to a recent chemical change (I doubt it).

Test: Turned on soap at the bay until running out of the gun. Closed of HP soap & wax at solenoid. So nothing should be coming out anymore. I still could count to 90 until the R/O water got a bit cleaner.

I have no ideas anymore.... Thanks for any input.

 

[MEP001]

Do you have an auto bay drawing from the same RO tank? You might have a failed check valve there.

 

[JustClean]

Yes, both my autos draw from the same tank. However, when I opened the pipe that comes from the R/O tank and feeds all the self serve R/O solenoids, the water was clean and cars of both autos come out clean...

 

[MEP001]

Assuming your RO tees in at the top of the boom, since you've eliminated anything backing up into the lines the only other thing I can think of is that the hoses are trapping some soap and releasing it in with the RO water. The only quick test I can think of to confirm this would be running wax through it for a few seconds, which should remove the soap from the lines.

 

[JustClean]

Assuming your RO tees in at the top of the boom, since you've eliminated anything backing up into the lines the only other thing I can think of is that the hoses are trapping some soap and releasing it in with the RO water. The only quick test I can think of to confirm this would be running wax through it for a few seconds, which should remove the soap from the lines.

I switched to soap to run it for a minute then I switched to wax until it came out and then R/O. No soap was coming out but the wax took again a long time to clear.
My next step would be to switch back to my HP soap and wax to see if they clear the line better. Fingers crossed. If you have any other suggestions please don't hesitate. Thanks a lot.

 

[JustClean]

I changed back to the old chemicals: same story. It takes at least about one minute to clear the line - either HP wax or HP soap.

Are my hoses getting too old and rusty so they trap soap (6 years)? My R/O pump has the same pressure as always...

 

[MEP001]

If it's the same every time in every bays, I'd suspect the lines. Does the RO tee in at the boom? If so, it wouldn't be a huge cost to replace them all in one bay to test.

 

[JustClean]

Another day - another test:

3.
Possible reason: Hoses to the bay old, retaining soap.
Test: Connected another long hose at the pump and checked the time it takes to switch over.

Result: It took about 40 seconds to change over which is still too long.

I am getting really frustrated. The other option I could think of is that maybe the R/O pump lost its strength to push the R/O water through? But it looks normal to me when it finally gets out to the gun and also in the auto...

PS Sorry forgot, the R/O doesn't tee in at the top of the boom but at the pump.

 

[MEP001]

It's not unusual to have a long changeover if it has to purge the bay line. One of the washes near us runs the RO through a separate pump at 500 PSI but runs it through the the same HP line to the bay, and the farthest one from the room takes a full two minutes to clear the line.

Is this something that only recently became a problem or are you maybe just noticing it for the first time? In either case, I'd strongly recommend running the RO to a check valve at the boom.

 

[JustClean]

Is this something that only recently became a problem or are you maybe just noticing it for the first time? In either case, I'd strongly recommend running the RO to a check valve at the boom.

Mep, I think you are right. I am getting to the bottom of this. It seems to be a combination of things. I can't say I fixed it but the time it takes to switch over has come down a lot. I replaced the pressure tank and the main check valve on the R/O pump. Both were...hmm...still okay but not 100% I think. The pressure of the tank may not have been right. The main check valve shutting off...but not 100% only 99%. Now I am down to 40 seconds at the farthest bay. I may have also never noticed it as I usually switch from HP rinse to R/O. But you are right: I am going to run separate hoses to the bay to eliminate that problem. Thank you again for your help