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

If you cannot find a drip, then it is probably a check valve. They all become old eventually, and not seat completely. A minor annoyance and on most water systems a bit of a job to replace the valve. Most RVers just live with it rather than try to fix it.

I would venture to guess 70% of the time it will be the city water inlet check valve not seating. Go to it and push it around a bit.

All 3 trailers I have been in and owned never bumped. EVER. So those that say it normal: maybe for your trailer but not the ones I have owned.

This indicates a slow loss of pressure.. This can be a dripping faucet, a leak somewhere in the system or the pump check valve letting pressure blead off back into the supply tank. OR: if you have a quick fill valve.. The QF valve may be leaking back to the tank as well.

Inspect for leaks, if you find none, then it's up to you weather you want to fix it or not. Mine is doing that as well just now.

Twomed wrote:
They are demand pumps. Designed to run when you turn on the faucet. More expensive pumps or adding a surge tank can make it a little more home like. If it runs periodically when all is turned of...you may have a leak somewhere.

I agree with this --- your very first response.

Our 1990 RV does not do that unless there is a leak --- somewhere (which can include a leak in the pump itself - draining back into the FW tank).

Ours never burps once the air is out of the system. First place to look for a leak is that stinkin' little plastic check valve in the fresh water connection. Replaced mine with a manual valve.

enblethen wrote:
That is not normal.
You could have a small leak somewhere.
It could be leaking back through the pump.
To start isolating problem, I would get a cap for the output of the pump. Disconnect outlet line, install cap. Listen for pump to cycle. If it does cycle, but not as often, pressure is leaking back through the pump. You can dis assemble the pump and look for something as small as a hair allowing this to happen.
If it does not cycle, the problem is in the rig's system. It could be water heater pressure relief valve, city water check valve, toilet ball valve.
Make and model of your rig would help.
What part of WA?

Or you could do what we did. Nothing. It has done it for 7 years now.

That is not normal.
You could have a small leak somewhere.
It could be leaking back through the pump.
To start isolating problem, I would get a cap for the output of the pump. Disconnect outlet line, install cap. Listen for pump to cycle. If it does cycle, but not as often, pressure is leaking back through the pump. You can dis assemble the pump and look for something as small as a hair allowing this to happen.
If it does not cycle, the problem is in the rig's system. It could be water heater pressure relief valve, city water check valve, toilet ball valve.
Make and model of your rig would help.
What part of WA?

Ok, if you don't have a visible leak in the system "after" the pump then your pump is leaking down, that is back into the freshwater tank! I can leave mine on all day and it may cycle a handful of times, and that is just a quick couple tenths of a second on/off!

Matt_Colie wrote:
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.....
Matt

Gonna disagree with you - the Shurflo in my 1999 Sunny can be left on all the time and only cycles when the water is in use.
Same with my 2000 Citation and my 1999 Class A.
So in my experience, "burping" is not normal.
If you really want to stop it, you may need to overhaul your pump or put a check valve in the input line to prevent reverse flow.

fj12ryder wrote:
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.

Had to be a coincidence.

Fresh water tank is suction side of pump.
Pump cycling is triggered by pressure switch on discharge side of pump

Is your fresh water tank really, really full? :B