Does anyone else's water pump do this....?

DanManz

Whenever we flush the toilet in our 2019 400 BDL, the water pump runs as expected during the flush and shuts off immediately after we let off the foot lever.  About three minutes later, the pump kicks on and runs for no more than one second.  After that, the pump shuts off and stays off just as it should.  This behavior seems to be related to the toilet as the pump never kicks back on after just using the indoor sinks or outdoor shower.  I don't see any evidence the toilet has a leak or is releasing water after the flush.  It sure doesn't use much water.  It's slightly disconcerting in the middle of the night as it always seems to happen just as I'm falling back asleep.  Does anyone else's pump do this and is there any reason for it?

pthomas745

Somewhere, your pump is seeing or sensing a drop in pressure.  There could just be the smallest bit of air entering through a faucet, or through one of the pipes, or a filter not completely tight, etc.  Usually, though the reports are of more consistent "running on" rather of just one second. 

In this thread (on a different issue) there is a discussion and video about adjusting the Shuflo pump pressure.  The pressure adjustment talk begins on the bottom of page one and continues on page 2, with a link to the video.  It may be a small adjustment to your pump might eliminate your issue.

https://tab-rv.vanillacommunity.com/discussion/5588/pump-problems/p1

ScottG

My pump has done something similar, but it's usually a random event in the wee hours of the morning that is not related to toilet use. I've always assumed it had to do with temperature changes causing very slight pressure changes in the system.

Your situation is curious. pthomas745's explanation seems most reasonable to me.

DougH

@ScottG Is that why they call it the wee hours of the morning?

ScottG

:-)

Bayliss

@DanManz, the below discussion thread might be helpful, including reviewing links to the videos it has:

https://tab-rv.vanillacommunity.com/discussion/6570/water-pump-not-pumping#latest

I agree with @pthomas745's comments.  Since this apparently is only happening after the toilet has been flushed, it would seem that there might be a very slight leak at the valve that releases water into the toilet bowl when you remove your foot from the flush pedal.  Since water will build up over the drain opening after each flush, it can be very difficult to detect a leak.  The best way to figure out if it is leaking is to (1) turn off the water pump; (2) drain the toilet bowl completely; (3) wipe out the toilet bowl and drain cover so it is dry, and let it air dry; (4) once it is dry, place a paper towel or kleenex in the toilet bowel down by the drain; (5) power "on" the pump at the control panel; (6) let it be for a few hours without flushing the toilet; (7) come back and see if the paper towel is wet.  If so, there's your leak.  You can do the same thing with the sink and shower, but that doesn't appear to be necessary, at least not yet.  [By the way, IF you have an outside shower, don't forget to look there for a possible leak.]

A couple other ideas:

Remove the filter cover on the pump and clean the screen.  It just screws off.  Read the thread I posted above.  I think it discusses it.  Be sure that the filter cap seats/seals properly when you re-attach it to the pump.

I remember reading on another site that this could possibly be caused by a bypass valve in your water lines not being fully open.  Apparently, this may fool the pump into thinking that it has reached its maximum pressure when the water is running and turn itself off.  I suppose it could work the other way and briefly turn the pump on, because it senses a slight drop in pressure.  Since it is easy and quick to do, check to confirm that the valves are fully open in "camping" (as opposed to bypass/winterization) mode.

Another interesting possibility that I have read about is that it could also be caused be the 'one-way' water valve (i.e., "check valve") where the external water hose hooks up to the trailer.  It was reported by one individual that they had that leak pressure when no hose was hooked up.  It was recommended that you try putting a hose cap on the water hose hookup threads (or screw in a plug) to seal that valve off from leaking pressure.  (NOTE:  That online post added that, "If the pump still cycles on, the one-way valve is OK and it is likely the pump."  I believe that the person who posted that info was expressing that if your water pump still cycles on and off occasionally (without running any water), then it isn't because the "check valve" is leaking pressure......rather, there is something wrong with the pump.....which might merely be an issue of it needing adjustment.)

Other than a bad or out of adjustment pump, the only other thing that might be causing the intermittent on/off of the pump is a partially blocked water line, which is discussed in some of the discussion threads on this forum.

Good luck!  Please be sure to let us know if you get it resolved.

DanManz

Thanks to everyone. Once I can get our camper off the road for a few days, I will investigate further and let you know. Making this whole thing even more strange is once I’m up to pressure, I can turn the pump off and drive all day. When we pull into a campsite for the night and I switch on the pump, it almost never runs to build up pressure. It’s amazing to me how tight the plumbing is and how well the system holds pressure. Once all the air is purged from the system, I never get any sputtering or anything less than a smooth flow.