Water pump operation question

[Tom C 47]

While using water from fresh water tank on our 2017 2800qs the pump comes on periodically for a second or two . This is while there is no use of the water and does not seem to effect the water level. Is this just the pump system just keeping the pressure available or should I be looking for a leak? I know the pump always comes on when we use water but this is just confusing to me. Thanks for any replies.

[sgtlm17]

It's possible you have a leak causing the system pressure to drop which in turn causes the pump to cycle to get pressure up again. It is also possible it's due to expansion and cooling down of your hot water. It can also be a small leak at a water shutoff point such as the toilet bowl trickling or an outside shower. Is the pump coming on frequently?

[rockfordroo]

You have a tiny leak somewhere. Doesn't take a lot to drop the pressure enough for the pump to come on. You wouldn't see it in the fresh water tank for DAYS, most likely.

[5picker]

How often does the pump kick on when not using water?

As mentioned...
A pump kicking on when no water is being uses typically points to a leak somewhere.
It can be a toilet valve, a faucet or some other very small leak.
It could also be leaking (ever so slightly) back past the check valve in the pump head.

I have seen sensitive pump pressure switches react to the air volume in the hot water tank expanding and contracting as it heats and cools.

[Tom C 47]

The pump comes on about every 10 to 15 minutes or so.

[rockfordroo]

Water is essentially "incompressible," so it doesn't take more than a couple teaspoons to drop the pressure enough for the pump to re-start.

[itat]

I had the same problem on my TT and discovered that one of the low point drains was leaking. My low point drains don't have ball valves, just a cap with a conical shaped seal. I replaced the gasket and the pump stopped cycling. I hope yours is just as easy to fix.

[BobHanke]

Check showers and make sure they are off at the handles....not the button on the shower head.

[roncurl]

I also had that issue on my motorhome. Searched and searched... ended up taking it in to the RV dealer I bought it from (had other issues to cover as well). As we chatted I mentioned that a while back I'd installed a valve to more easily winterize the camper (it didn't have a built in one). Well, long story short, that was the problem. I probably didn't close the valve ALL the way when it was last used. With a little tightening the pump has stopped running every 15/20 minutes. It's the simple things that annoy me! I have knack of over thinking a problem!

[McCormickJim]

Another likely problem, in addition to a possible leak, is the "back-flow preventer valve" is leaking due to failure or debris in it.

When all faucets are off, you'll hear your pump run for a few seconds to build pressure. When the pressure is built up, the pump stops running. Between the pump and your faucets is a back-flow preventer that prevents water from flowing back to the pump.

When the back-flow preventer is faulty or has debri in it that prevents it from fully closing, water seeps back to the pump. After enough seepage, the pump comes on for a few seconds to build pressure.

Your leak may be at a faucet or elsewhere as identified by others in this thread OR you may just have a faulty back-flow preventer valve.

Search "How to replace rv backflow preventer" on Google for ideas on how you can check and replace the valve yourself.

[HikerBob]

Check the water heater pop-off valve as that was the problem with our same issue. There was a tiny leak and just a little drip on the side of the trailer when water built up in the sheet metal liner around the water heater. Stand aside and pop the valve, but do be careful not to scald yourself. By "pop the valve" I mean pull up on the lever and release it quickly so the spring can re-seat it. If the problem continues, turn off the water heater and the water pump, release the pressure in the hot water line and open the pop-off valve until water flow stops. Pull and rotate the lever letting it pop back in several times. This will hopefully clean out calcium or other mineral build up in the valve. Hope this helps.

[Photo Lab]

The most frequent issue I have found wasn't mentioned above, and is not really harmful, such as a leaking faucet/connection would be, but rather a leaking check valve on the water pump outlet. this can be either a separate in-line check valve, or an integral part of the water pump, generally caused by a small piece of debris in the valve.

If you are of a mind to make a repair, shut off water to the pump, remove it and then remove the three long screws that hold the assembly. Remove the diaphragm, and flush everything clean with water. You will frequently find something like a very small grain of sand in the pump. If your pump is an old one, and the rubber parts are perished, the easy fix is installing a new pump head, which may be bought at most RV dealers. A lot cheaper than a new pump! In our 37 years of RVing, I've cleaned out a number of check valves, both integral to the pump, and separate.

[mypalal51]

I found a leak at the little element filter just in front of the pump. It is plastic and the weakest point in the system

[sgtlm17]

Originally Posted by mypalal51

I found a leak at the little element filter just in front of the pump. It is plastic and the weakest point in the system

That is before the pump and should not affect pressure in the water system

[CedarCreekWoody]

The leak may be inside the pump itself, allowing water to drain back into the tank. In case you will never see the leak.

[Jonol]

Check for a leak at the city water inlet, the automatic valve might be leaking.
On mime I put a plug wen I do not use city water.

[joe1141]

we had the pump bleeding off on our flagstaff. All it needed was an adjustment on the pump with the set screw on the side of the pump. half a turn in and pump no longer bleed off and runs every hour or so. All is good.

[rockfordroo]

Originally Posted by joe1141

we had the pump bleeding off on our flagstaff. All it needed was an adjustment on the pump with the set screw on the side of the pump. half a turn in and pump no longer bleed off and runs every hour or so. All is good.

You just raised the pressure so it takes longer to bleed off. You didn't fix the leak.

[Rokslinger]

aDo you have an icemaker inbyour fridge?

[Wolverine 1945]

Pump will also run from time to time if you have air in the system !!!