Rebuilt CAT 310 Pump...now no High Pressure

[Car Washer]

Last week I had a hose break on top of the building. Prior to that everything worked fine. I fixed the hose, but after fixing I had a lot of pulsing at the wand. I changed out the tip (it was clogged) with no change... pressure was great, but still a lot of pulsing, so I inspected the pump ( CAT 310) and it had a slow leak at the bottom by the little tray where the wicks sit . I shut down the bay for the week and ordered a rebuild kit. Last night after rebuilding the pump I went to test it and the pump would not start when High Pressure functions selected. The motor starts...belt turns, but no High Pressure. After a minute or so it trips the "reset box" and shuts off the motor. Low pressure functions work fine. What could be wrong?

Side note the last time this bay did this ( Low pressure functions work...High Pressure doesn't) it was the rotary switch in the meter box. Could it really be a coincidence that a hose breaks, pump leaks and now its a rotary switch...all in a week?

 

[Randy]

When you had the pump head open did you happen to check the ports for wash out or erosion? Check to make sure you have water going to the pump, disconnect the water supply to the pump to verify that you have water to the pump. It almost sounds like to have a plugged up hose. Try this disconnect the hose that goes out to the bay, attach a short hose and gun to the discharge of the pump and turn the pump on.

 

[Dick Nitro]

Start by checking the pump valves. Half the time a bit of metal or crud or thread tape can wash its way into the suction valves after I tighten all the fittings back down when rebuilding, especially if I’m reusing old brass fittings.

While the top (discharge) valves and plugs are out, look down inside and spin the pulley by hand and verify that the plungers are thrusting back and forth properly. Of course - MAKE SURE YOUR BREAKER IS OFF when doing this or any maintenance.

if there’s nothing obvious wrong with the aforementioned, inspect your suction line check valve from the water source. The springs can separate from the poppets in a worn check and will starve your pump. If you can verify that your pump is receiving and sending water but still has almost zero pressure, I’d be looking for a leak somewhere between the pump and the wand.

 

[Dick Nitro]

Also… make sure the regulator isn't totally unloaded

 

[Greg Pack]

If you have gravity feed only sometimes you have to prime the pump. Take the hose off at the pump and try to start it. If it doesn't start moving water you need to check the pump inlet for proper flow.