Fluctuating pressure

Steven Button

Steven Button

Administrator
...seems to be one problem after another just now with my hot water skid... I've now got a slight fluctuation in pressure with the trigger gun on (between 2800psi and 3000psi), there is no fluctuation when in bypass mode.

I think I've ruled out an inlet side leak - I noticed a lit of vibration at the pump from what looks like a loose belt. Can a loose belt cause pressure fluctuation?

What else should I be looking for? There are about 370 hours on the pump, oil level is good.

Can it be the unloader - last night there was a loud 'knock' about 3 or 4 times when I let the pressure off.

Thanks for anyones thoughts!! :indecisive:
 
Steven Button said:
...seems to be one problem after another just now with my hot water skid... I've now got a slight fluctuation in pressure with the trigger gun on (between 2800psi and 3000psi), there is no fluctuation when in bypass mode.

I think I've ruled out an inlet side leak - I noticed a lit of vibration at the pump from what looks like a loose belt. Can a loose belt cause pressure fluctuation? Yes it can

What else should I be looking for? There are about 370 hours on the pump, oil level is good. No leaks around the pump head?

Can it be the unloader - last night there was a loud 'knock' about 3 or 4 times when I let the pressure off. Could be...but usually won't fluctuate. The pressure goes, and doesn't come back

Thanks for anyones thoughts!! :indecisive:
Click to expand...
........
 
Belts always look loose to me when they're running. Is the fluctuation fast like the needle is shaking or slow up and then back down? The times I had a belt slip the pressure would slowly go down and up as the belt would catch and slip. I always think the unloader is the first suspect also. Maybe it will go away.
 
This is a long shot but we keep losing psi and our rig was in and out of the shop with no help. We found a hose that had a cut inside the house. Look for a soft spot in hose.
 
That sounds like the slipping belt to me. If you can get a look at the pulley and you see the spokes 'changing' as they spin thats the pulley slowing as the belt slips - you could test it by spraying some belt dressing on it and see if that stops it but change the belts even if it does. Have a good look at the belts to see if they're slick or messed up - good luck!
 
I had a similar problem with the pressure changing. I REPLACED my belts with the correct size and it is steady as a rock now. I tried the unloader first and it didn't help.
 
Guy Blackmon said:
I know this sounds stupid, but check your inlet filter. And please don't ask me why!!!!:banghead:
Click to expand...

That was my first port of call... a few grains of dirt, still the same after cleaning.

The one good thing about the breakdowns is that I'm learning more about how the equipment works, not the manner in which I want to learn, but I've got to stay positive. :yes4:
 
respect the tech

Russ, good call..
pressure-feed it for a fast answer..
It's another good reason to have a "dual-source option" on your pump system..
the troubleshooting would have taken less than 5 min..
check the water filter,
check the unloader for bypassing to the tank when the gun is open,
pressure-feed the pump to find leaks,
check the belts for tightness,
then, call a tech ! No time for guessing.
...Stop wasting time away from contract-sales !
If you let a tech show you how fast he can do the troubleshooting,
you also get to have him explain it to you..
That is the fastest and best "education" you can get.

by the way, if you have the system tank-fed,
and the bypass already flowing back to the holding tank..
make sure the thermal relief valve is removed from the inlet of the pump..
it will suck-air at the damndest time,
and it might NOT leak when you do the pressure-test !

everyone of you needs a tech..
find one locally, ask LOTS of questions,
and ALWAYS tip him ! Nobody wants to work for free. :meeting:
Remember this.. it helps him to grow you.
The guys that don't respect the tech, don't get the best prices. Eh?
Also, if the local tech is not prone to helpful answers.. find a new service center.
this is one important aspect of mangement you MUST learn, to grow a successful business.


call or e-mail me for Dual-feed plumbing images.
I share more than just attitude.:dirol:
 
... I forgot to post my results... :nono:

It was loose belts that were the problem this time - relatively easy fix (other than having to get under flatbed to unbolt skid, jack skid up to get to the bolts, then put it back together... lol). Been working like a charm again!

Hey Jerry, can you email me the dual feed plumbing images please? Is it literally two feeds into directly into pump?

thanks to everyone for all their help.
 
PLUMB your pump for reliability.

Yep, dual lines will balance the feed-flow into the pump..
remember the last set of seals you replaced..??
the one farthest from the source had the most "rat-bites" Eh?
cavitation eats the seals FAST !
"the perfect water supply" feeds the pump evenly as possible, with unrestricted flow.
feed a 5 to 6gpm pump with dual 5/8" lines from a 1" filter.
feed a 7 to 8gpm pump with dual 3/4" lines, with dual 3/4" filters, from a 1 1/4" line.
feed a 10 gpm pump... NOT !!.. they are too expensive..
get dual 5gpm pumps for less cost, less expensive seals,
..less downtime (from special-order parts).
You could get electric clutches on both, and still have lots of money left over,
and even longer-term lower-cost... my favorite (business-related) words.

e-mail me for images info@PressureWasher.net
I'm glad to help.
 
My accountant told me free troubleshooting assistance is "non-profit"..
I showed him my repeat-customer rate..
..he got all quiet.
:nhl_checking:
 
Russ Spence said:
my first stop would definatly be the unloader
Click to expand...

Ditto, pressure loss is either seal kit needed or worn unloader. I hate Belt Drive I dont care what anyone say's Gear Drive is rock solid.
 
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