Low Pressure Cat 310

[864real]

I just purchased a 4 bay SS. Its my first one and trying to do my own service on equipment to know how everything operates. 3 of the bays run at 1000PSI (plan to increase) but have one that is at about 500. Was thinking first order would be a pump seal replacement, but is there something else to look at first? Do regulators go bad? If so, how do you know if pump or regulator causing low pressure? What else should i be checking?

Also, to increase the pressure, do you just tighten the brass fitting that comes out of the top of regulator?

Thanks for the help.

 

[MEP001]

Knowing how crap these check valves are, I'd start there. The tell-tale sign that it's failed is that all the other bays will weep when this pump is running.



The nut on the regulator does adjust the pressure, but do not crank it up. Those very rarely fail and cause low pressure. I can't tell you how many times I've fixed problems caused by people cranking the regulator down trying to solve a low pressure issue. It's almost never the regulator.

 

[864real]

Thanks for the response.

I don't get a weep at other bays. What is that valve used for? to release pressure or something when servicing?

If that isn't leaking, and likely not regulator, would pump seals be next steps?

As for cranking it up, would going from 1000 to 1200 psi be considered "cranking it up". or are you talking about in this situation when the pressure is really low like this one with 500 psi and trying to get it up to 1000

 

[Randy]

Does the pump pulsate?

Is the belt tight on the motor?

What size nozzles/tips are you using on your guns? I like 1505 nozzles

Do you have any check valves leaking by, weep, presoak, tire cleaner etc. I'd start by disconnecting the 2 weep hoses at the bottom of the check valve, start the pump and see if you have water coming out of the check valve, if you do the check valve is bad. The check valve is there to stop high pressure from back feeding into the weep system.

Have you removed the valves looking for any broken O rings or debris in the valves?

To raise the pressure tighten down on the brass nut on top of the regulator stem. Only do this like MEP said after you correct the current problem you have. I run my 310 pumps at 1500 psi.

 

[MEP001]

The check valve I pointed at is for the weep, or freeze protection. If it fails, the other bays will weep and there will be a loss of pressure. So that's probably not bad, yet.

 

[2Biz]

I've never seen a pump plumbed where the weep had to flow through the head to get to the HP hose! And I doubt I would use a Swing CV on the inlet water supplies to keep weep from backfeeding the gravity tanks...If you are in a cold climate and your tanks overflow in the winter, the swing cv's would be the problem. I wouldn't trust them the way they are needed to work in this design....The picture below is a much better design. Weep is injected into the HP hose out to the bay. A 2000# Rated SS CV is used to keep weep water from backfeeding into the pump and gravity tanks. When the pump is running, the second cv between the weep line and HP hose keeps HP from back feeding the weep. Much better and robust design.

Also, if the weep supply is daisy chained to each pump, I would think it would be problematic keeping the weep to each bay regulated consistantly. I attached a picture of what I designed so you can see the difference. And there is a difference! The ball valves on my weep system is for a semi-automated air blowdown, washer fluid injection system I have for closing down and winterizing during extreme cold. Usually -5° and colder. I ripped out the old system and designed/installed this system about 10 years ago. I haven't touched the needle valves since I installed it.

 

[MEP001]

I've never seen a pump plumbed where the weep had to flow through the head to get to the HP hose!

I have, many times.

And I doubt I would use a Swing CV on the inlet water supplies to keep weep from backfeeding the gravity tanks

There are swing checks that have a plastic seal on the flap that seats 100%.

if the weep supply is daisy chained to each pump, I would think it would be problematic keeping the weep to each bay regulated consistantly.

We in the south only weep 2-3 days a year. I tend to throttle back the main weep supply, but some people just run it full blast.

 

[2Biz]

I really don't understand your response? If you don't remember, I started out with a "Supposedly" Top Of The Line Mark VII Pump Stand. It was plumbed in a way that was virtually impossible to work on. I don't know if this was intentional on the engineers part (for service $$$) or they just had their heads up their a$$! Anyway, just trying to educate the new operators that there are many ways to build a pumpstand. Some work long term, some don't or create more issues than necessary!

 

[MEP001]

It's just input, not meant in any way to be a critique of your comments. I do remember, I've done a rebuild of the same stands, and I'm still not 100% happy with the outcome, mainly that the guys I did it for have made some not-so-smart changes to it that have caused some complications, and now I'm running it and dealing with the problems they caused.

 

[864real]

So still having the low pressure issue when in use.

When the gun is not running the pressure is at 1000psi as expected (pressure regulator set to 1000). As soon as water flow starts, pressure goes to about 600psi. Swapped nozzles with another bay and the pressure loss is still there, so not the nozzle tip. The pressure drop happens on both gravity fed and city supply water so thinking not a supply issue. Pump does not sound cavitating or different than other pumps. Did a seal replacement and all looked ok. Checked belt and oddly enough this is the best belt of the 4 and is tight (have to replace other 3 now that have cracks in them). I removed the line from bottom of check valve when running and no water was coming out to confirm cutoff for weep is good.

So the pump will make pressure, but seems not when there is any volume of flow. Any thoughts on what to check next?

 

[2Biz]

You need to set pressure with the gun trigger pulled. BUT if you have a 400psi difference between trigger pulled and not, then you seem to have a regulator issue. You should not see more than 50-100PSI difference between trigger pulled and not, as long as you have weep guns. 400psi difference is too much bypass pressure. Do you have a spare regulator to install? Or try swapping the regulator with a known good running bay.

 

[MEP001]

Are there check valves at the boom? One of those could be bad and pressure is making its way back through. Spot free would be a likely culprit since you'd probably see the others overfill.

It could be the regulator. Normally I would pinch off the bypass hose to see if anything is flowing, but yours has a high pressure hose which you can't pinch closed. You could replace it, or try loosening the nut all the way with the pump off, leave it a couple threads with no tension but make sure it's still engaged, then turn on the bay with the trigger pulled and adjust it. If there's a piece of debris caught in the regulator, that should let it flush out.

 

[Randy]

Here's a easy and fast way to determine if the equipment down stream of the pump is to swap hoses at thepump andseei f the p\low problem goes with the hose or stays at the pump. If it stays with the pump then you know you have a pump problem, if it goes with the hose then you know you have a problem down stream of the pump.

 

[864real]

There are no check valves at boom and we don't have spot free rinse. I think Randy has a great idea with swapping the hoses to the bay and I will try that next and try to flush the regulators. Thanks

 

[MEP001]

Did you ever check the tip?

 

[864real]

Yes, swapped tips between 2 bays and same pressure issues. I've order 2506 tips but don't have yet. Currently has 4008 tips.

 

[864real]

MEP, you mentioned backing regulator off all but a couple threads, but that makes pressures really low. I did that. But wasn't sure if that would be for and unloader vs regulator.

 

[MEP001]

Either, they regulate the same way. You have a Paraplate BR5-2 balanced pressure regulator.

 

[2Biz]

try to flush the regulators.

How do you flush a regulator?

 

[2Biz]

MEP, you mentioned backing regulator off all but a couple threads, but that makes pressures really low. I did that. But wasn't sure if that would be for and unloader vs regulator.

When you tried doing what Mep suggested, did you try setting pressure with the bay gun trigger pulled? Do you have a spare BR5-2 regulator?