Small dripping at the gun

[stampedecarwash]

Hello I have a super savor ColemanHanna for wand wash. One of our bays has some small dripping at the gun/wand. Here is what I have checked so far:
1.Thought it might be the diaphragm in the solenoid valve for Rinse (which is normally closed) but no water comes out of that line when I open it from the Cross where hot water gets connected to (so the diaphragm is doing its job and the valve is normally closed unless the customer opens it by choosing the Rinse option).
2. Also thought it might some how be related to the check valve under the hot water tank and again no luck after changing the valve. One thing for sure, when I shut of the ball valve under the hot water tank the dripping stops (that's why I changed the check valve).
3. Also checked the spot free to make sure the plunger hasn't been left open, and nope no water comes out of the manifold (so plunger is good and closed).

 

[MEP001]

Does it still drip if the valve from the hot water tank to that bay is closed? It might need the spring tension from the check valve to keep it from running through with gravity since the tank is higher than the gun. Maybe also see if it stops dripping if you raise the gun higher than the tank.

 

[slash007]

I'm almost 100% certain you just need to install a check valve above the bay. I had to do that to all of my bays to stop dripping. It is just siphoning water from the tank and you need to install the check valve so that it introduces air and breaks the flow after being used.

 

[TheTallGuy]

I have the exact same problem.

 

[stampedecarwash]

Problem solved: Noticed this is the only bay with no check valve in front of the spot free line before teeing to everything else on the boom.(Don't ask me why, I guess previous owners didn't care enough) . Added the check valve and BOOM.
You might ask if there is was no check valve how come no high pressure water was coming back. So I should clarify that there was a check valve but after spot free was Teed to the tire cleaner. But now I also added a check valve between spot free and tire cleaner. I know weird setup.
here is a pic before adding the check valve. sorry didn't take a pic after and don't feel like going up there again, haha, but its between those two orange ends on the pic.

View attachment 1163