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.

 

[Car Washer]

I cannot for sure point to what actually was wrong, but your advice helped me get it going. I went back and tried the simplest thing first... which was to disconnect the outlet hose(the one going to the bay) from the deregulator as I remember that being the one nearly clogged with gunk from being so old( thanks Randy) Thinking this may be what might have sent trash into the pump or be clogged in general.
I then turned the water on to see if there was flow and there was... coming through the deregulator which reminded me that I had cleaned it... totally drying it to make sure there was no loose trash in it (thanks Dick).
Then I reconnected the hose and did a test run thinking the little bit of water in the deregulator might be enough to get things going. Took a little bit, the pump started making all kinds of racket, but thought it was trying to get going, so I crossed my fingers and let it keep doing its thing. It smoothed out, but my pressure was in the 2000 range when the trigger was pulled in the bay, so I dropped the pressure back to 1500 and things seem to be working fine!

Thank you all for the help...you never disappoint!

 

[edredtop]

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?

Remove the belt and see if there is abnormal resistance when you turn the pulley.
Pull the head and re-inspect the seals. It's not unheard of to mix up the high pressure and low pressure seals. If that happened you may have bits of seal (metal or rubber) interfering with your unloader making the pump (thus the motor) work harder and trip the breaker.
And I hope you ordered two kits so you don't have to wait a week next time.