Spot Free and Soap/Bubble

[stampedecarwash]

Hello, In at least two of my bays I noticed in the middle of the spot free function, some soap/bubbles come out for few seconds, once when I washing my own car, and once a customer complained(He had a fairly clean car already just did a rinse and then spot free) . Then I tried to do rinse and spot free in all of the bays and it never happens. I kind of feel like maybe soap was already on the car??? I keep checking the quality of the SF tank and all the bays and they are all consistently 10ppm. Also checked the hot water tank quality (thought maybe a bad check valve make some soap/wax goes in to the tank), but the ppm is the same as City hot water ppm. (hot water has more ppm than cold water). I even tried to use soap in one bay and SF in another bay (thinking if the bays are some how related or there is an electrical issue making the soap solenoid valve to open for few seconds), but still the quality is 10ppm. Has anyone seen something like this before?

 

[MEP001]

Does your spot free tee in at the top of the boom with a separate check valve? I've had issues before where the spot free check valve doesn't seat 100% with low pressure (presoak and tire cleaner) and a little backs up into it and waits until spot free is engaged. If that's the case, you won't re-create it going from rinse to spot free.

 

[stampedecarwash]

Thats exactly right, I did pre-soak, Rinse and the SF and all of bays do that and I see some soap comes out but it goes away pretty soon...Is that normal? Should I really change all the check valves where SF meets the line?

 

[PaulLovesJamie]

I think I have sort of the same situation that you describe - about 5 seconds after selecting SFR, I get a small amount of soap/bubbles for a second or 2.
MEP might have the answer for you, I think I'll check into what he suggested. But I'll mention what I've always assumed to be the cause:
I think that for a typical customer, they use the low pressure functions first, then high pressure soap or rinse. I suspect that when they switch to high pressure, there is still some residual pressure in the LP lines, which is "held" there by the higher pressure of the soap or rinse cycle. Then, when they switch to SFR -- I have a 1 second delay timer on the SFR function to reduce cycling of the motor -- it gives it that 1 second to release the backed up low pressure lines, which results in a small amount of PS/TC/etc being released into the manifold, which I then see at the gun a few seconds later.
(btw, yes I do have separate check valves on everything at the manifold above the bay, including the sfr.)

 

[MEP001]

...I'll mention what I've always assumed to be the cause:
I think that for a typical customer, they use the low pressure functions first, then high pressure soap or rinse. I suspect that when they switch to high pressure, there is still some residual pressure in the LP lines, which is "held" there by the higher pressure of the soap or rinse cycle. Then, when they switch to SFR -- I have a 1 second delay timer on the SFR function to reduce cycling of the motor -- it gives it that 1 second to release the backed up low pressure lines, which results in a small amount of PS/TC/etc being released into the manifold, which I then see at the gun a few seconds later.

I've seen that same problem as well, but mostly on washes that have braided hose for the LP functions. I prefer nylon tubing, and I put tire cleaner, presoak and air into the same check valve, and I don't have a problem in that setup.

 

[Jeff_L]

I agree that you should check the sfr check valve above the bay. It’s the first culprit I always look at with this symptom.

 

[stampedecarwash]

changed the check valve to a brand new stainless steel check valve and exactly same thing. Its kind of a good news meaning its supposed to be like that and no need to change all bays check valves. The customers need to accept the fact that before actual spot free water comes out the line, sometime (depending on what the previous customer has used) there will be sopa for 1-2 seconds which they can easyli rinse it with the actual spot free. Cheers....