WW 2.0 loss of high pressure

[WashFixer]

I've got a Water Wizard 2.0 that that I can only get 600psi on the HP rinse. I pulled apart and cleaned out the unloader and was able to get 800psi for about 30 seconds, then back down to 600. there is no water returning to tank through the medium pressure solenoid. There is no leaks that I can find.
It seems to me like it is either an unloader issue or HP seals in the pump (Cat 3535). What do you guys think? Thanks!

 

[MEP001]

I test the unloader by pinching off the bypass hose. Coleman may use a steel braided hose, but I could do this with the D&S units I used to service because they used a polybraid hose. If you don't feel any water getting through the bypass hose, the problem is with the pump or the belts are slipping.

 

[Greg Pack]

I've never really had a problem with the unloader that a set of o-rings wouldn't fix. Is it running smooth?

I see you looked for hose leaks, A couple other things I can think of is a RP solenoid stuck open that is allowing HP in both the rocker panels and HP oscillating nozzles at the same time. Also, there is a Dema dump valve on the boom that could be stuck open. You probably would notice, but thought I'd mention because I'm guilty of overlooking the simple things all the time.

As big as a pain as it is to rebuild the 3535 on a wizard 'd take quick look at the valves too.

 

[WashFixer]

Thanks for the ideas, I like them all.
When I was there yesterday I noticed when the HP rocker cycle comes on it makes a nice 1200psi so that tells me pump and unloader are fine and it seems like there must be a leak I'm missing somewhere.
I'll check out that dump valve on the boom, do you know what it's for or can I get rid of it?

 

[Greg Pack]

The dump valve is located under the boom cover, I believe on the driver's side. I think it may be only on units with onboard dryers but I'm not 100% sure. It is a dema medium pressure solenoid. It opens at the end of the wash for a few seconds when the dryers kick on, I assume to drain the lines and prevent nozzle dripping.

Along with that, the standard HP nozzle sizes on the wizard are 6-#6 SS turbos on the boom, 12-0503 IMEGS on upper spraybars and 6-0504 IMEGS on the lower spraybar. It wouldn't hurt to check those nozzle sizes and maybe just going ahead and replace them. I replace mine annually. I just use 1506 IMEGS in the boom and 0503 IMEGS everywhere else.

 

[WashFixer]

That is good info on the nozzles, thanks. I just replaced all the cartridges on the turbos with #8s since that's what was in them, but next time maybe I'll do #6s and save some water

 

[Greg Pack]

I believe the rocker panel uses the #8 and the boom uses #6