Cat 310 Hammering

[Jerry33]

I've had a total of 3 carwashes with 22 bays all with cat 310s in my 33 years as a self-service wash owner and thought I'd seen and repaired it all. I have one now that I cannot stop pulsating and hammering. I replaced the valves and checked for cylinder wash out; replaced the head; replaced the entire pump (and the bearings were bad on the one I took out but didn't stop the pulsating), replaced that head; replaced the pressure regulator; shut off the weep and the soap and wax feeds; water feed from gravity feed hotwater tank and from city are ok; check valve to the HW tank ok as there is no push back into the tank. Of course I remove the tip from the wand before testing and makes no difference. what am I missing?

The pressure gage shows a dip and surge of only a few pounds but the slapping of the hose in the trough is horrible and the trigger gun jumpinf with the ratta-tat-tat of the hose makes you think you have the rifle on full automatic.

All of the changes to equipment and hoses makes no difference at all. Same pulsating rhythm.

what is left to check

thanks. jdf

 

[Dick Nitro]

oh my lord, I went through a similar head banger few months ago… it was terrible. Overhauled one of my pumps for basically no reason

very very long story short, maybe have another look at your suction check and make sure there’s no issue there. Make sure the nipple isn’t screwed in too far or the flat of the poppet will barely clear the nipple rim when the pump is running and it will starve, causing the pulsing. Only screw the nipple enough to get it to seal, don’t bottom it out. Attached is a pic of what NOT to do.

 

[Dick Nitro]

It will trick you because water will flow freely through the hose and check from the gravity tank and you’ll think there’s no obstruction, but it will starve the pump after a few seconds of running. I honestly love troubleshooting, but this one was traumatic for me. Best of luck

 

[Jerry33]

oh my lord, I went through a similar head banger few months ago… it was terrible. Overhauled one of my pumps for basically no reason

very very long story short, maybe have another look at your suction check and make sure there’s no issue there. Make sure the nipple isn’t screwed in too far or the flat of the poppet will barely clear the nipple rim when the pump is running and it will starve, causing the pulsing. Only screw the nipple enough to get it to seal, don’t bottom it out. Attached is a pic of what NOT to do.

Nitro,
what "feed" is this attached to and is that a check valve the nipple is screwed into? Looks like it could be the city water feed and I don't have check valves on those hoses. All of my washes were designed and built by Magic Wand, now long gone, and none have (or had) check valves. I did not check the pressure or continuous flow to that pump from that supply line and I will now. When disconnected i did open the shut off valve and shot water 3 feet or so but but I should have let it flow for longer than that. Might be a partial blockage. If the nipple you are showing is to the soap/ wax feed, then I have totally shut those off and again no check valve in any of the other pumps. Same with the week which does have a check valve but again I pinched off the hose and it had no effect. I will change the check valve anyway to see if that makes a difference. thanks

 

[Dick Nitro]

I’m referring to the main water inlet to the pump, not the soap.

if you’re inlets are plumbed to pressurized city water, then the situation I’m describing is less likely, but still worth looking at.

in my experience, the biggest “WTF is wrong with my pump” issues are - something obstructing the suction/inlet OR air being sucked into the pump suction from a hole or loose fitting/swivel on the suction line. Air can also ingress from loose fittings on the regulator return line.

here’s some pics of my inlet check valve for clarity.

 

[Jerry33]

It will trick you because water will flow freely through the hose and check from the gravity tank and you’ll think there’s no obstruction, but it will starve the pump after a few seconds of running. I honestly love troubleshooting, but this one was traumatic for me. Best of luck

Nitro,

Funny. Oh does that give me a flash back from a couple of days ago. I forgot how much pressure the gravity feed has until I disconnected the hose without draining the tank. If I had a video of it I'd win the DUMMY AWARD as the water shot out of the open 3/4 inch brass pipe and my trying to reattach the pump hose to it caused it spray in every direction and soaked me from face to feet. Hard to think when all he** is breaking loose but I finally decided to let it flow and drain the tank. It just "boiled" upward instead of 360 degrees in all directions. What a mess.

I didn't check the solenoid that opens and shuts off the city water supply because I have a shut off valve on that hose and so I shut it off and the system is designed to allow free flow from the gravity tank (previously a hot water tank, now only cold in it) and there was no difference in the pulsations.

From your other suggestion, I'll check the pressure and flow from the city supply.

thanks,
jdf

 

[Jerry33]

I’m referring to the main water inlet to the pump, not the soap.

if you’re inlets are plumbed to pressurized city water, then the situation I’m describing is less likely, but still worth looking at.

in my experience, the biggest “WTF is wrong with my pump” issues are - something obstructing the suction/inlet OR air being sucked into the pump suction from a hole or loose fitting/swivel on the suction line. Air can also ingress from loose fittings on the regulator return line.

here’s some pics of my inlet check valve for clarity.

Nitro,
Thanks for the advice. Got to go to the Wash now.
jdf

 

[Jerry33]

Nitro,
Bingo! I checked the city water feed, plenty of water and pressure; Checked the gravity feed again and lots of water and ample pressure. However, I did replace the inline check valve to the gravity setup and the pump runs smoothly and oh so quiet! FINALLY.

I benched checked the check valve afterwards and it works perfectly but it went into the trash. All effort of changing heads and pumps and valves and endless hours of checking this and that was for naught (except the first pump body change revealed a grinding noise when turning the belt pulley so it was a matter of time for that to crap out).

Thanks for making me check the water input again. Cross your fingers it is still working ok when I go there tomorrow. Gremlins and all that are always working in my absence.

jdf

 

[Dick Nitro]

Nitro,
Bingo! I checked the city water feed, plenty of water and pressure; Checked the gravity feed again and lots of water and ample pressure. However, I did replace the inline check valve to the gravity setup and the pump runs smoothly and oh so quiet! FINALLY.

I benched checked the check valve afterwards and it works perfectly but it went into the trash. All effort of changing heads and pumps and valves and endless hours of checking this and that was for naught (except the first pump body change revealed a grinding noise when turning the belt pulley so it was a matter of time for that to crap out).

Thanks for making me check the water input again. Cross your fingers it is still working ok when I go there tomorrow. Gremlins and all that are always working in my absence.

jdf

Great news! Fingers are crossed.