CAT Pumps 1540E - Pressure Issue

[rshiggaon]

Hello I have a CAT Pumps 1540E installed in my IBA, but it’s only reaching 400 PSI and won’t go any higher. So far, my technician and I have replaced the following components:

• Gauge
• CAT Pumps 31770 NBR Seal Kit with Stainless Steel Spring (for the 1540 Pump)
• CAT Pumps 31775 NBR Valve Kit
• General Pump YUB21405 Brass 21 GPM Trapped Pressure Unloader with Blue Spring (rated for 4500 PSI)

Despite these replacements, the pressure hasn’t increased at all. My technician inspected the pump head but didn’t find any visible issues. He’s now considering replacing the pump head, though he didn’t detect any clear signs of damage.

I’m not sure what’s causing the issue. Am I overlooking anything? Should I proceed with replacing the pump head, or would it be better to replace the entire CAT pump? I’d appreciate any advice you can provide. Thanks

 

[I.B. Washincars]

I would suspect a bad check valve somewhere, letting HP water back up somewhere...possibly into the RO tank. Unless the pump is pulsating, I wouldn't think the problem is there. Are you SURE that the belt is not slipping?

 

[pcb]

Does it have a low pressure option controlled by a solenoid opening and sending water back to tank? If so, solenoid may be stuck open.

 

[rshiggaon]

I would suspect a bad check valve somewhere, letting HP water back up somewhere...possibly into the RO tank. Unless the pump is pulsating, I wouldn't think the problem is there. Are you SURE that the belt is not slipping?

The pump is not pulsating; it produces a smooth sound. There are no check valves on the HP lines. The output of the CAT pump goes directly to the gantry HP tips, and there’s no visible leakage. A hose break would be noticeable, but that’s not the case here.

I haven’t yet checked if the belt is slipping, but it doesn’t make any unusual noises. I’ll verify and provide an update here. Good Point.

 

[rshiggaon]

Does it have a low pressure option controlled by a solenoid opening and sending water back to tank? If so, solenoid may be stuck open.

No, we don’t have anything like that. The output of the CAT pump goes directly to the tips on both sides of the gantry.

 

[Keno]

One thing I was told to try on SS pumps on this forum is to hook a bay hose and gun directly to the pump outlet to eliminate anything down stream as a diagnostic test. Probably can do something similar on a bigger cat pump also.

 

[rshiggaon]

One thing I was told to try on SS pumps on this forum is to hook a bay hose and gun directly to the pump outlet to eliminate anything down stream as a diagnostic test. Probably can do something similar on a bigger cat pump also.

This is a 3/4-inch HP hose. I will have to take several steps to make it work as you describe, lot of pain and new fittings.

At one point, I pinched the hose with a vise wrench to check if the pressure would increase. However, I vaguely recall that it didn’t make much of a difference. I need to repeat this test, will update here what I find out.

 

[Fatboy769]

@rshiggaon, do you have any pictures of your pump setup and/or pump stand?

 

[rshiggaon]

@rshiggaon, do you have any pictures of your pump setup and/or pump stand?

 

[rshiggaon]

This is a 3/4-inch HP hose. I will have to take several steps to make it work as you describe, lot of pain and new fittings.

At one point, I pinched the hose with a vise wrench to check if the pressure would increase. However, I vaguely recall that it didn’t make much of a difference. I need to repeat this test, will update here what I find out.

The pump is not pulsating; it produces a smooth sound. There are no check valves on the HP lines. The output of the CAT pump goes directly to the gantry HP tips, and there’s no visible leakage. A hose break would be noticeable, but that’s not the case here.

I haven’t yet checked if the belt is slipping, but it doesn’t make any unusual noises. I’ll verify and provide an update here. Good Point.

Update:

• Inspected the belt: no signs of slipping or noise.
• Attempted to pinch the output hose: couldn't pinch it much, but the gauge needle moved slightly (hair).
• Confirmed no check valves on the high-pressure hose; the hoses run directly from the pump to the IBA tips.

 

[Keno]

Did this start suddenly or over time? What kind of tips? Are they new? Worn out tips causing too much flow demand and decreased pressure? You sure your gauge working correctly? Just throwing out ideas. You can still test with a regular bay gun with an adapter in pretty sure. Turn your regulator all the way down and increase regulator pressure slowly with the bay gun attached to make sure your pump can make full pressure.

 

[rshiggaon]

Did this start suddenly or over time? What kind of tips? Are they new? Worn out tips causing too much flow demand and decreased pressure? You sure your gauge working correctly? Just throwing out ideas. You can still test with a regular bay gun with an adapter in pretty sure. Turn your regulator all the way down and increase regulator pressure slowly with the bay gun attached to make sure your pump can make full pressure.

We noticed this issue a few months ago and have tried various approaches to resolve it. As for the timing, I’m not sure if it happened suddenly or developed gradually over time, but I suspect it’s the latter. The only change I can recall was adjusting a few tips 2–3 months ago. I plan to revert to the old tips to see if that resolves the issue.

Additionally, to eliminate any ambiguity, I’ll install a regular bay gun next week as several people have suggested, and test it out. I’ll share updates once I have the results.

Thank you for all the pointers.

 

[chaz]

Debris in tip. Missing tip. Or worn tip.?

 

[rshiggaon]

I identified the root cause, the tip size was larger for a few of the new ones we replaced a few months ago. Using a regular bay gun and checking the pressure helped pinpoint the issue.

Another problem solved, thanks to the thoughtful input from this group. Much appreciated!