Do ALL Rv's do this? If I leave the water pump on..

Suzzee,

For the first (and only the first) year that a potable pump is in service, it will not do as you describe. After that, they all do. The 40+yo PAR thumpers used to take two years to start, but after that....

Unless you are real sure of your situation, enjoy it. When you hear it, you know that the pump working and you have water in the tank. On one very rare occasion, the as less than expected. I later found that one of the system drains was dripping - about one drip every three minutes. When I fixed that it when back to one thump every half an hour or so. That is often due to the internal leakage of the pump valves - I have discovered.

Matt

Maybe it shouldn't have, but the pump would cycle periodically when no water was in use, and it didn't do it after I capped the tank.

I agree that it shouldn't have made any difference, but it sure was a coincidence. :) I didn't do anything else, just the cap. Go figure.

We use city water 99% of the time, so I suppose if you use the water pump a lot, a small loss of pressure over time could certainly occur as things expand and contract.

fj12ryder wrote:
Our pump stated doing that, and it definitely is not "normal". We found that our fresh water tank had a very slow drip at the outside drain point. I put a cap on it and the problem was solved.

Mine haven't done it other than that one time. You just have a very slow leak somewhere. Finding it could be an adventure. :)

If you are talking about your water heater pop off valve, then it is very dangerous to cap that off. If you are talking about the water tank, then a drip there will not cause the pump to short cycle! Chris

Dog Folks wrote:

SuzzeeeQ2012 wrote:
ok, detective work it is thanks everyone :)

Also check the pressure relief valve of the water heater. Ours will "weep' and the pump will kick in for a split second every 1/2 hour to offset the small water loss.

Yup. I used to experience the same thing - on the current and 4 previous RVs.

I have found that over time, the air gap in the hit water heater is taken up by water. The smaller the air gap is, the higher occurrence of the pump "blip".

When heat cycles occur, water expands slightly... Air compresses, water does not.

Part of my "arrive at the campsite setup routine" now includes opening the HWH relief valve (pump off of course) until no water flows out... Snap it shut.

The blip almost never occurs any more.

SuzzeeeQ2012 wrote:
to clarify: it will run a bit when I'm NOT using the pump...if it's left on, but not used.

perfectly normal if it’s not happening often… mine will cycle on like that every hour or two…

Old-Biscuit wrote:
a short burrrrup......good luck locating that source.

this is what I think is normal, not a 2 second run every hour.

Running every once in a while means plumbing system has lost just enough line pressure to close the pressure switch on pump and pump cycles.

Could be a very small leak/drip
Could be the internal check valve in pump leaking back to fresh water tank
Could be city water connection check valve drip
Could just be the change in pressure from water heater as the water heats and cools a bit (water expands/contracts when heated/cooled)

When it runs for a couple of seconds before shutting off then you have a leak.

A short burrrrup......good luck locating that source.

Our pump stated doing that, and it definitely is not "normal". We found that our fresh water tank had a very slow drip at the outside drain point. I put a cap on it and the problem was solved.

Mine haven't done it other than that one time. You just have a very slow leak somewhere. Finding it could be an adventure. :)

SuzzeeeQ2012 wrote:
ok, detective work it is thanks everyone :)

Also check the pressure relief valve of the water heater. Ours will "weep' and the pump will kick in for a split second every 1/2 hour to offset the small water loss.

SuzzeeeQ2012 wrote:
every once in a while, it will run for a second as if you're using the water.

Consider it normal.