CAT 310 Pulsation/Hammering Start Up

[JAM]

Hello- looking for a little help on this one as I can’t seem to pin point the issue. Short of replacing the entire pump.

I have been trying to figure out what’s going on with one of my bays pulsation/hammering on start up. When starting the HP rinse the system will pulsate badly for 30-45 seconds and then come out of it and start running smooth. This only happens in this 1 bay.

The issue coincidently started when my weepmizer started running continually during cold temps. The longer it weeps and sits without running the worse it gets. When I stop the weep it seems to be fine on start up.

I am running a CAT 310 Pump- gravity fed hot water line. I have rebuilt the pump, installed new valves, installed a new pressure regulator, checked water flow, replaced the hot water line check valve, checked for leaks, I have cleaned the water tank filter, etc. I even tried putting a check valve behind the weep line Dema valve thinking maybe water was getting away.

Nothing seems to cure it. Any other ideas? What am I missing? I have attached a video on start up.

 

[Randy]

Is your weep water going though the pump? If it is try connecting it to the high pressure line with a high pressure check valve and get rid of that galvanized nipple, galvanized fittings and pipe have no place on car wash equipment.

 

[JAM]

The weep is going into the inlet of the pump. All 3 of my pumps are set up like this one. Only this one is giving me issues for some reason.


I was running a husky 307 air diaphragm pump recycling weep up until this year with no issues.

Any reasons for someone plumbing the weep into the inlet side of the pump?

 

[mucoucah]

Did you ever figure it out?
I had similar problem.
Turns out there were a handful of things: unloader discharge was going back to tank, which increased the suction flow a lot and made the pump cavitate. The suction hose would have been ok for the normal flow, but the extra from from unloader was too much.
I piped the return to the suction. But then the T was too close and the hose had no give (braided). I replaced with a flex hose, added some piping to the unloader return was about 1ft away from suction, and added a pulsation dampner (it never had one before).
This made a huge difference.

These cat 310 run rougher than the 5cp. My previous 310 killed itself so i made all these changes until it calmed down a bit.

 

[JAM]

Did you ever figure it out?
I had similar problem.
Turns out there were a handful of things: unloader discharge was going back to tank, which increased the suction flow a lot and made the pump cavitate. The suction hose would have been ok for the normal flow, but the extra from from unloader was too much.
I piped the return to the suction. But then the T was too close and the hose had no give (braided). I replaced with a flex hose, added some piping to the unloader return was about 1ft away from suction, and added a pulsation dampner (it never had one before).
This made a huge difference.

These cat 310 run rougher than the 5cp. My previous 310 killed itself so i made all these changes until it calmed down a bit.

I ended up having too much weep water flow pressure. I adjusted using the needle valve to reduce the amount of water.