Pressure Washer Diagnosis

[Beamer]

Our pressure washer, rated for 2000 psi, is now maxing out at about 1300 psi.
We've had it many years but it's not overused by any means and it's just occasional residential use through the years.
I tried a couple new nozzles around the original provided orifice size with no change.
What should I be looking to to find the issue?

 

[Jswain]

Our pressure washer, rated for 2000 psi, is now maxing out at about 1300 psi.
We've had it many years but it's not overused by any means and it's just occasional residential use through the years.
I tried a couple new nozzles around the original provided orifice size with no change.
What should I be looking to to find the issue?

Do you have a picture or model number?

 

[Beamer]

Dirt Killer H200 with Kranzle pump.

In general though, what could cause lower pressure than design spec?

 

[Jswain]

Dirt Killer H200 with Kranzle pump.

In general though, what could cause lower pressure than design spec?

I would start by removing & cleaning out the 3x suction & 3x discharge valves on the pump. Pretty easy place to start. Assuming you already checked the water inlet screen.

Was asking about the pump as some of them are non serviceable.

Dirt in the valves could keep them from closing completely, could be a dislodged or torn oring etc.

 

[M635_Guy]

I would start by removing & cleaning out the 3x suction & 3x discharge valves on the pump. Pretty easy place to start. Assuming you already checked the water inlet screen.

Was asking about the pump as some of them are non serviceable.

Dirt in the valves could keep them from closing completely, could be a dislodged or torn oring etc.

This man pressure washers

 

[rust in the eye]

Helpful to know is gas or electric. They operate differently.

 

[Beamer]

This man pressure washers

The screen had no debris other than a little surface rust in places. I haven't found a replacement listed. The tract was clean with no debris which was a little bit of a surprise as the feed plumbing is before our house filter for the well.

I pulled the six valves and again the tract appeared clean and free of debris. I suppose there could be unnoticeable grains of sand in the valves so I'll take a closer look. Something was a bit odd the three of the valves are different than the other three in that there are short intregral plastic tangs on three that appear to be limiters designed to hit on the screw in caps. On the other three the tangs are not attached to the valves but rather captured loosely in slots in the insides of the caps. I wondered if the tangs had sheared off the vavles but that wouldn't account for the slot in the caps.

Overall, anything I've taken off where there is water flow looks really clean.

I don't know if the pump oil has any affect but it's color looks due for a change. Unfortunately it's a odd one with a label stating Synthetic 5w50 and imprint on the fill cap showing 15w40. I've read (not in the manual) it should be non-detergent and I'm guessing a synthetic oil like Mobil 1 is going to be detergent.

 

[Beamer]

Helpful to know is gas or electric. They operate differently.

Gas.

 

[Beamer]

I never recall touching the control valve jamb nuts on the pressure control knob into the unloader but that's not to say it wasn't dittled with in the far past. Would the unloader have anything to do with the reduced pressure?

 

[LopezBart]

These are constant displacement pumps, so the pressure is set by the flow rate through the nozzle. Either your pump is worn and pumping less, or the nozzle is worn and letting too much water through.

 

[Beamer]

These are constant displacement pumps, so the pressure is set by the flow rate through the nozzle. Either your pump is worn and pumping less, or the nozzle is worn and letting too much water through.

I mentioned early on that new nozzles of different orifices were tried with no change.

I don't know how long they last but I think it's a commercial setup based on the 10 year warranty and current listings.
It's been over 10 years but it's only been used for personal residential maintenance so not that many hours on the clock. I'd be surprised if it's 50.

Do the pumps draw water from the hose or just use what is delivered?
Question is to rule out the feed hose from the water supply which I didn't suspect until now.

 

[LopezBart]

I mentioned early on that new nozzles of different orifices were tried with no change.

I don't know how long they last but I think it's a commercial setup based on the 10 year warranty and current listings.
It's been over 10 years but it's only been used for personal residential maintenance so not that many hours on the clock. I'd be surprised if it's 50.

Do the pumps draw water from the hose or just use what is delivered?
Question is to rule out the feed hose from the water supply which I didn't suspect until now.

The feed hose must be able to supply more water than the pump needs. If it doesn't the pump may cavitate and this will damage the pump. One way of checking is to have a pressure gauge on the feed line; it should show positive pressure at all times. It sounds like the bypass or unloader may be malfunctioning, though.

 

[Beamer]

The feed hose must be able to supply more water than the pump needs. If it doesn't the pump may cavitate and this will damage the pump. One way of checking is to have a pressure gauge on the feed line; it should show positive pressure at all times. It sounds like the bypass or unloader may be malfunctioning, though.

The pump documents note that it can be run dry, not that it has.
I have not heard any banging or other odd noises from the pump that might indicate cavitation as I understand it.

Back to the question, does the pump draw water in making for the potential of collapsing a flexible hose?
The hose meats the minimum size specified but is a different one than used in the past.
I'm just trying to take it off the list.

 

[seber]

No inlet filter after a well pump. I'd suspect a worn pump. It doesn't take much sand.

 

[LopezBart]

Back to the question, does the pump draw water in making for the potential of collapsing a flexible hose?
The hose meats the minimum size specified but is a different one than used in the past.
I'm just trying to take it off the list.

The hose should feel under pressure when things are running. If it feels slack, you need more water flow.

 

[rust in the eye]

Aside a worn pump (OP stated like this since new, no?)could be bypassing, restricted inlet or plain BS claim by manufacturer.
I'm curious to know how OP knows actual pressure.

 

[rust in the eye]

I never recall touching the control valve jamb nuts on the pressure control knob into the unloader but that's not to say it wasn't dittled with in the far past. Would the unloader have anything to do with the reduced pressure?

I sure think so.

 

[gizardlizard]

For future reference, use pump saver after every use and you’ll never have issues. Hard water has minerals in it and they can wreak havoc on pumps once dried out.

 

[Jswain]

Have you checked with another gauge that it is reading correctly? When you say you changed orifice sizes in the tips, you mean color, or actual orifice size? As they are sized for the output of the pump so if you installed one that was 2000psi @ 3gpm and your pump is 2gpm it would obviously be less then 2000psi

If you actually changed the orifice size to a smaller orifice and the pressure didn't increase I would say it's likely bypassing in the pump, whether it's in the valves or the module itself, cracked pistons etc. or the unloader is stuck unloading at a given pressure

 

[Beamer]

For future reference, use pump saver after every use and you’ll never have issues. Hard water has minerals in it and they can wreak havoc on pumps once dried out.

That's exactly what the manufacturer said today but rather to prevent seals from drying out.
Where is that available?

 

[Beamer]

Have you checked with another gauge that it is reading correctly? When you say you changed orifice sizes in the tips, you mean color, or actual orifice size? As they are sized for the output of the pump so if you installed one that was 2000psi @ 3gpm and your pump is 2gpm it would obviously be less then 2000psi

If you actually changed the orifice size to a smaller orifice and the pressure didn't increase I would say it's likely bypassing in the pump, whether it's in the valves or the module itself, cracked pistons etc. or the unloader is stuck unloading at a given pressure

No I haven't tried another gage. Oem american made gages are costly.

I tried different orifice sizes around the specified one, all the same color and new. Same pressure.

I previously mentioned that three of the 6 valves have broken nubs off their tops that project into the caps. A replacement valve kit is ordered to give that a try
.
After that, if not resolved, I plan to get an unloader rebuild kit to refresh the O rings, etc as suggested by the manufacturer.

It's being an education.

 

[Beamer]

No inlet filter after a well pump. I'd suspect a worn pump. It doesn't take much sand.

The pump has a strainer at the hose inlet. There wasn't a speck of anything in there other than slight surface rust on part of the strainer but not blocking the openings. Replacement is ordered.