Pump Pressure

[borumrm]

I have a cat 310 pump that has been in service for a number of years. Yesterday I noticed the pressure gauge on the pump showed only 500 psi when the handle was pressed. I turned the regulator a few turns to the right and the pressue did not increase however when the customer releasesd the handle the pressure shot up to around 1700 psi.

So...what first...change the regulator, the gauge or rebuild the pump. Regardless of which I will need to order a part as I used my last regulaor and gauge last weekend at my other wash and have not ordered replacements yet

 

[MEP001]

When the pump can't produce pressure at a given flow, turning the regulator up does nothing. When the trigger is released, the flow is decreased and the pressure shoots up. So your regulator is not the problem. Either the pump needs work (Is it pulsating?), it's sucking air through a leak or it's not getting enough water.

 

[slash007]

I have a cat 310 pump that has been in service for a number of years. Yesterday I noticed the pressure gauge on the pump showed only 500 psi when the handle was pressed. I turned the regulator a few turns to the right and the pressue did not increase however when the customer releasesd the handle the pressure shot up to around 1700 psi.

So...what first...change the regulator, the gauge or rebuild the pump. Regardless of which I will need to order a part as I used my last regulaor and gauge last weekend at my other wash and have not ordered replacements yet

Seems like you need to replace your high pressure seals. I had a couple of pumps that were stuck on 500 psi and once the HPS were changed it worked perfectly.

 

[cantbreak80]

My first step in troubleshooting low pressure is to replace the spray tip. An old erroded spray tip oriface might be one or two sizes larger than spec, increasing flow and decreasing pressure. A trigger gun's weep oriface is smaller than the spray tip...that's why the psi jumped to 1700 with the gun closed.

 

[slash007]

My first step in troubleshooting low pressure is to replace the spray tip. An old erroded spray tip oriface might be one or two sizes larger than spec, increasing flow and decreasing pressure. A trigger gun's weep oriface is smaller than the spray tip...that's why the psi jumped to 1700 with the gun closed.

I second what cantbreak80 says. The first place to start is always to check the nozzle. I learned the hard way after replacing many parts one time trying to chase down a low pressure problem and all along it was just a worn nozzle.

 

[PaulLovesJamie]

spray tip/nozzle is important, but a bad one will not result in the symptoms you described.
I'll bet its the high pressure seals, possibly the valve(s).
I recommend checking the high pressure (outlet) valves first because you can check them in 10 minutes for a total cost of $0. If they look OK change the seals.

Now that I think about it though, MEP suggests looking at water supply and an air leak, that could cause your symptoms and is also a whoppin $0 to check out so I'd also look into that before I spent $ on seals/valves.

 

[2Biz]

If its the High Pressure seals, how could the pump build 1700psi on the gage? My guess is its the pressure regulator. What kind of regulator is it? I use Giant Unloaders and when they start to go bad, the pressure is all over the place.

 

[MEP001]

If its the High Pressure seals, how could the pump build 1700psi on the gage? My guess is its the pressure regulator. What kind of regulator is it? I use Giant Unloaders and when they start to go bad, the pressure is all over the place.

Unless the seals are so completely worn that they've all but disintegrated, the pump can reach a high pressure like that if the trigger is not pulled. Besides, the fact that the pressure didn't come up like that until he turned the regulator up tells me that there's nothing wrong with it.

 

[borumrm]

All good suggestions...It's about time I changed the tips anyway so I will do that first and pump / pressure is not pulsating like it is starved or sucking air. I did notice where I noted on the side of this pump that it was put in service back in 2002. I am betting it is time for a rebuild. Luckily I have a brand new spare pump on the shelf so I can replace it then rebuild the other when time allows. Heck if I have to do that I might as well replace the regulator at the same time...it looks pretty old and I did not mark on that one when I put it in service...I need to remember to do that .....thanks for all the good feedback.

 

[Ghetto Wash]

If the weep is introduced into the high pressure side of the pump there will be a check valve there to prevent high pressure from entering the weep system. If that CV goes bad it will cause the exact problems you are describing. Easy to check. Either remove the weep line to that bay and turn the pump on and see if it is leaking or leave the line on, turn on the bay and see of other bays are weeping when the problem bay is on.

 

[2Biz]

It's about time I changed the tips anyway so I will do that first and pump / pressure is not pulsating like it is starved or sucking air. I did notice where I noted on the side of this pump that it was put in service back in 2002. I am betting it is time for a rebuild. Luckily I have a brand new spare pump on the shelf so I can replace it then rebuild the other when time allows. Heck if I have to do that I might as well replace the regulator at the same time...it looks pretty old and I did not mark on that one when I put it in service...I need to remember to do that .....thanks for all the good feedback.

If you change the pump, regulator, and the tip all at the same time, then we'll never know what the culpret is!

 

[slash007]

If you change the pump, regulator, and the tip all at the same time, then we'll never know what the culpret is!

Lol exactly! I always like knowing what the problem was, so one item at a time is the way to go even if you go back after and replace the other components. Unfortunately a few times I ended up changing all of the components and then the problem turned out to be something else completely.

 

[2Biz]

I'm still sticking with it being a faulty regulator. When it goes into bypass, it shouldn't hit 1700 psi. Mine don't anyway (If its working right), maybe the pressure increases by 50 psi or less. And if it is a tip, how does it noticeably go from 1200psi to 500psi unless someone drilled it out.

Slash, I hope he takes your suggestion and fixes one thing at a time and reports back. This is the fun part, seeing if you guessed right or not.

 

[MEP001]

I'm still sticking with it being a faulty regulator. When it goes into bypass, it shouldn't hit 1700 psi.

Remember the first thing he did when the bay was running low pressure was turn the regulator up.

 

[borumrm]

I am definitely going to do one thing at a time...I am like everyone else I like to know what the heck corrected the issue. My plan is going to be as follows:
1-Change the tip and check
2-Change the regulator and check
3-Change the check valve for weep and check
4-Change the pump

Unless you all have other thoughts or ideas of other items that need to be inserted. I really appreciate all the suggestions and I will post the results.

 

[slash007]

I am definitely going to do one thing at a time...I am like everyone else I like to know what the heck corrected the issue. My plan is going to be as follows:
1-Change the tip and check
2-Change the regulator and check
3-Change the check valve for weep and check
4-Change the pump

Unless you all have other thoughts or ideas of other items that need to be inserted. I really appreciate all the suggestions and I will post the results.

Good luck. I would start with the tip but don't forget to add the high pressure seals to the list.

 

[MEP001]

I would start with the tip, but then I'd look at the weep check valve. The quickest way to check that would be to see if any or all bays are flowing what looks like weep when the bay with low pressure is running. If that's not the problem, instead of changing the regulator I'd test it. Tie off the trigger and run the bay, then pinch off the bypass hose from the regulator. If no water is flowing through the hose, the problem is not with the regulator.

 

[soapy]

Kleenrite has a good video of how to service the cat 310 pump. It shows you exactly what you need and how to do it. In addition to the seal kits be sure to have the cat tool PU33004 spanner wrench for removing the brass valves. You can also go on You tube and see several other companies that have servicing videos of the 310.

 

[ted mcmeekin]

Don't forget belt tension--we just went through this drill and last check was belt tension--which of course was the problem.

Ted

 

[borumrm]

OK...I know I am behind on this but I finally got around to changing the tip in the first 3 bays and here are the results. The original issue was pump pressure on bay 1 showed 1280 when bypassed but only 750 with handle pulled. I decided the check my first three bays and compare...found another issue....

Bay 1
Before Tip Change
Bypassed 1280 psi handle pulled 750 psi

After Tip Change
Bypassed 1400 psi handle pulled 900 psi

So tip change made a pretty good difference. I might be able to get a bit more pressure adjusting the regulator

Bay 2
Before Tip Change
Bypassed 1500 psi handle pulled 1000 psi
After Tip Change
Bypassed 1500 psi handle pulled 1200 psi

Interesting no change in by pass pressure but increase of 200 psi after tip change. Is it normal for bypass pressure to stay fixed?

Bay 3
Before Tip Change
Bypassed 1100 psi handle pulled 1100 psi
After Tip Change
Bypassed 1100 psi handle pulled 1100 psi

So what is the issue here? I am thinking regulator what say yee all?