Low water pressure on 2 of my bays

[BigVic1993]

Good evening
wanted to thank everyone for the advice and help on my issues at my carwash i am new to this so its a work in progress.

i have 2 bays for some odd reason i only have 200 to 400 psi when i usually run my pumps at about 800 psi
i have replaced both pumps with brand new GIANT P56W pumps and it did not fix the issue all my other bays have great pressure
any leads on what else could be my issue

Thanks

 

[edredtop]

Check your spray tips for foreign objects, sometimes a bit of debris can plug the tip just enough to do weird things. Next check your unloaders. Here's an example of one...
3/8” Brass Balanced Unloader | Brown Spring | 7100 | Kleen-Rite (kleen-ritecorp.com)

 

[BigVic1993]

Ive checked every possible thing. ive replaced both pumps and nothing now. i gave up for the night and going to try tomorrow morning. ive checked for debris and all in the lines. all it seems to do is cavitate.

 

[MEP001]

It could be a leak in a line allowing air to draw into the system. Is the pressure up to 800 PSI with the trigger released, then when the trigger is pulled does the pressure drop immediately, or does it take a few seconds?

 

[BigVic1993]

without pulling the trigger the gauge shows 200 to 400 psi and when i pull the trigger it just cavitates and the pressure don't move at all just gets lower and that is with the new pump installed my belts are tight on the motor and water pump.

 

[MEP001]

Cavitation is caused by a restriction in the water supply. You may have pulsation caused by something else.

the pressure don't move at all just gets lower

So does the pressure not move at all or does it get lower? It has to do one or the other.

 

[edredtop]

Putting a new hose and trigger on at the pump in the equipment room, bypassing the unloader, will take everything downstream out of the loop and may be helpful. (Tape or hold the trigger open when you run the test)
I've had a restricted hose from the equipment room to the boom cause low pressure before.

Cavitating... restrictions or air leaks on the inlet side of the pump? Fresh rubber hose (like heater hose on an automobile) can collapse when placed under a vacuum especially if you have a dirty screen on the inlet. Is there a commonality between the two pumps like a shared water supply? Have you checked your soap and wax supply hoses to see if they are cracked and allowing air...? Are your soap and wax solenoid plungers tight, o-rings good? Fittings installed with teflon tape and snug?