CAT310 pump

Have two CAT310 pumps with issues.

One comes on as normal at 1300PSI but drops to 600-700PSI when wand handle is pulled. I changed all six valves as they looked worn. Issue did not improve.

Other pump comes on as normal to 1300PSI but drops like the other pump plant pulsates. Checked those valves too but the ones removed looked newish so I probably changed them recently.

Before I remove the head wondering what else to check or remove or replace that could cause the issues. Does not feel like the regulator since pumps come on to expected PSI. Any ideas?

I probably will replace the regulator next.

The first pump could very well be a regulator issue. I'd swap the regulator from a known good regulator if I didn't have spare. The second pump has a seal problem or the head is washed out. Your going to have to pull the head off and inspect the seal seating surface of the head.

Have you replaced the nozzles recently? Belts good?

Greg Pack said:

Have you replaced the nozzles recently? Belts good?

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Yes to both

Try the Check valves on the pump suction. After a lot of hell, this is the first thing I inspect when I have pump issues

Roz said:

Have two CAT310 pumps with issues.

One comes on as normal at 1300PSI but drops to 600-700PSI when wand handle is pulled. I changed all six valves as they looked worn. Issue did not improve.

Other pump comes on as normal to 1300PSI but drops like the other pump plant pulsates. Checked those valves too but the ones removed looked newish so I probably changed them recently.

Before I remove the head wondering what else to check or remove or replace that could cause the issues. Does not feel like the regulator since pumps come on to expected PSI. Any ideas?

I probably will replace the regulator next.

Click to expand...

Question: Why would your system be at 1300 PSI when the trigger is not pulled? Shouldn't the unloader drop that pressure until there's a demand? I think mine run at about 150 PSI until there's a demand (trigger pull).

The second problem can be caused by a foreign object in the valves, even if they are brand new. Check all 6. I had a utility meter reader throw his monthly plastic lock out tags in my water reservoir a while back that coincided with a brand-new pump installation. I found a piece of his tag in one of the valves after a pulsation problem developed.
(yes, I have in-line screens now on the intakes )
Also, any kind of intake restriction can cause a seal to be dislodged/damaged causing a pulsation too.
Definitely change one regulator to see what, if any effect it has.
Let us know what happened, love a happy ending.

edredtop said:

Question: Why would your system be at 1300 PSI when the trigger is not pulled? Shouldn't the unloader drop that pressure until there's a demand? I think mine run at about 150 PSI until there's a demand (trigger pull).

The second problem can be caused by a foreign object in the valves, even if they are brand new. Check all 6. I had a utility meter reader throw his monthly plastic lock out tags in my water reservoir a while back that coincided with a brand-new pump installation. I found a piece of his tag in one of the valves after a pulsation problem developed.
(yes, I have in-line screens now on the intakes )
Also, any kind of intake restriction can cause a seal to be dislodged/damaged causing a pulsation too.
Definitely change one regulator to see what, if any effect it has.
Let us know what happened, love a happy ending.

Click to expand...

No that is not how CAT pumps in the self service bay work. You set the initial high pressure rinse pressure by adjusting the regulator. Many owners set this psi to 1000-1100 but it is a personal preference. We like to have a higher initial psi as our customers really appreciate the extra pressure. The wand has a nice feel for them. When you pull the trigger this allows more water thru the handle so the pressure drops anywhere from 100-250 psi from the initial high mark depending on the tip used. Pulsation is often caused by a particle in a valve. When I change valves I change all 6 so they age at the same rate/time. I usually blow air from a can into the opening before replacing the new valve. This usually will dislodge anything that could clog a valve. In talking with CAT tech support they recommended new seals for the pistons and to inspect inside the head. That’s the next move when I return to the wash. If something was stuck inside the wand tip I should see issues initially and when I pull the trigger. I am just seeing the issue when the trigger is pulled. The tips are new so anything inside would be gone when I replaced them. My guess is that the seals need to be replaced inside the head.

Roz said:

No that is not how CAT pumps in the self service bay work. You set the initial high pressure rinse pressure by adjusting the regulator. Many owners set this psi to 1000-1100 but it is a personal preference. We like to have a higher initial psi as our customers really appreciate the extra pressure. The wand has a nice feel for them. When you pull the trigger this allows more water thru the handle so the pressure drops anywhere from 100-250 psi from the initial high mark depending on the tip used. Pulsation is often caused by a particle in a valve. When I change valves I change all 6 so they age at the same rate/time. I usually blow air from a can into the opening before replacing the new valve. This usually will dislodge anything that could clog a valve. In talking with CAT tech support they recommended new seals for the pistons and to inspect inside the head. That’s the next move when I return to the wash. If something was stuck inside the wand tip I should see issues initially and when I pull the trigger. I am just seeing the issue when the trigger is pulled. The tips are new so anything inside would be gone when I replaced them. My guess is that the seals need to be replaced inside the head.

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Ive always set my pressure in self serve bays adjusting the regulator with the gun trigger pulled in.

Since you have two pumps having same issue are you sure there not being starved of water? Are they both drawing from same tank? Is there check valves on the incomming water supply that could possibly not be opening all the way. Not sure of your set up. Ive always found seals to be more of an issue for pulsating than valves. I defiantly have had a lot of valves have stuff stuck in them but seals usually does it for me. Thats just me though.

Roz said:

No that is not how CAT pumps in the self service bay work. You set the initial high pressure rinse pressure by adjusting the regulator. Many owners set this psi to 1000-1100 but it is a personal preference. We like to have a higher initial psi as our customers really appreciate the extra pressure. The wand has a nice feel for them. When you pull the trigger this allows more water thru the handle so the pressure drops anywhere from 100-250 psi from the initial high mark depending on the tip used. Pulsation is often caused by a particle in a valve. When I change valves I change all 6 so they age at the same rate/time. I usually blow air from a can into the opening before replacing the new valve. This usually will dislodge anything that could clog a valve. In talking with CAT tech support they recommended new seals for the pistons and to inspect inside the head. That’s the next move when I return to the wash. If something was stuck inside the wand tip I should see issues initially and when I pull the trigger. I am just seeing the issue when the trigger is pulled. The tips are new so anything inside would be gone when I replaced them. My guess is that the seals need to be replaced inside the head.

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I've only been doing this for 21 years at 4 locations with 22 Cat 310s what do I know?
You must use weep guns. I'm in Cali and don't. That may be the disconnect.
My "idle pressure" is around 150 PSI and when the customer pulls the trigger, the unloader ups it to our predetermined 1200 PSI.
Checking the valves for a FO is super easy as you know and personally would be my first check unless you know it's probably time to replace the HP and LP seals.
I totally agree with Blanco's take above.
You're right on the tip, I've never had a pulsation from a blocked tip, just weird spray patterns or no pressure.
Good luck Roz

Yes we have weep guns. Interesting, never knew about the different approach starting with a lo psi. Are your pumps 310?

Setting the psi when handled pulled is also news to me but i guess it depends on your teacher. I do wonder if that is a bit risky as the delta in psi can vary based on the size of the tip. We use an 05 but do experiment from time to time with an 06 and 07 as well as different gun handles to see how they perform. If you set the psi when handled pulled then the top psi may go higher than you expect which I was told is not good for the pump. I know the 310 can go up to about 2200 but was told a long time ago not to exceed 1500 on a regular basis. Anyhow I may remove the new valves and blow more air into the openings as I do get the feeling that the issue is with the valves.

I am constantly learning whenever I talk with other owners so I do appreciate hearing how others do things at the wash. The nice aspect about our business is that there is more than one way to achieve a great customer experience.

We do not have check valves on the water supply, just a large backflow preventer. Our city water psi is great at 80-90psi. May has been a slow month here given a lot of rain so issue with us being slammed in all 6 bays. I do wonder if a handle can be bad however recently replaced the handle in one of the bays in question.

Thx for the ideas.