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Running hot and cold to SS pumps

Dan-Ark

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Replacing the tank system on our second wash. I have hot water plumbed to my Etowah valley low pressure tank rack. The pumps are fed from both sides of the manifold/head. one side has a solenoid valve wired to the rinse cycle, this side also has the lines feeding HP soap and HP wax. I do not know if the soleoids are NO or NC. It would seem to me I would want hot water mixing with the soap and wax and cold water rinse. the way I have it the hot water will come in the opposite side of the pump from the wax and soap, Is this correct? does the solenoid open cold water for rinse and city water pressure stops the hot water intake? or is the soap was hot water supposed to be on the same side and the solenoid closes forcing cold water to rinse? there is no guarantee that it was working right before because the prior owner did not have gas to the hot water heater working. Here is a pic of one of my pumpsl not sure why its upside down.pump3.jpg
 

MEP001

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Everything should come in on the same side of the pump, otherwise you'll get excessive turbulence which will cause cavitation, which will destroy your manifolds. Cat installation manuals require all liquid comes in one port and exits one port, but specifies they be on opposite sides. FWIW, I've plumbed all pumps in the last 15 years with the inlet and outlet on the same side, with the regulator also on the same side and the bypass routed to the same inlet. I prefer to plug the other inlet and I put only the pressure gauge on the other outlet, and since doing so I've stopped having washout issues completely. Before that I had to replace or repair 9 manifolds on one six bay car wash over a three year period.

All the solenoids in question (soap, wax, and rinse in the picture) are normally closed. You should have a check valve on the hot water line, and cold via the rinse solenoid just holds the hot water check valve closed and overrides the hot water.
 

Dan-Ark

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Thanks, so it is correct with the solenoid on the cold which makes sense if it is NC. I should move the hot water to the same side as the cold water and the soap wax feeds. there are check valves at the the hot water tank on the line to each pump. It seemed odd to expect enough draw on the soap and wax on one side and the water supply on the other, but this wash has been like that since 1989 or older. MEP, you have not steered me wrong yet and have helped me many times. Thank you.
 

MEP001

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I generally don't have any issue with soap and wax drawing no matter how the pump is plumbed, unless the water tank is significantly higher than the soap/wax tanks. It looks like you have a swing check valve on the hot water line - I prefer these, which have a captive spring and gasket so you won't have parts coming off the check valve and ending up in the pump, and it has a gentle amount of restriction on the water flow that seems to help the pump draw soap/wax.


FWIW I also see that you have a high pressure (JE Adams) check valve on the soap/wax line. I remove any check valve there and use the old D/H trick of plumbing those solenoids backwards. The spring pressure is enough to keep them closed against draw, and they act as their own check valve against the rinse pressure. One less thing to go wrong...
 

Dan-Ark

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the soap and wax are fed through solenoids in a manifold block. I'm not sure I could reverse those.
 

MEP001

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the soap and wax are fed through solenoids in a manifold block. I'm not sure I could reverse those.
No, only if you had individual solenoids for each function and each bay.
 
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