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MVH1's avatar
MVH1
Explorer
Mar 18, 2018

8 y/o Fresh Water Tank Pump

I have never used our fresh water tank pump and it’s 8 y/o. We are planning a big trip this summer and will be using it. What kind of maintenance should I perform on the pump before our big trip? Thanks
  • raston wrote:
    Regarding a 'short cycle' once in a while... it will even do that as the water heater cools down and the pressure in the tank drops (ever so slightly) as the water cools / contracts. Nothing to worry about.


    Interesting. I always understood that the air gap in the tank prevented that. I have only seen the pump kick on randomly two ways. Number one is when it has a leak which I have seen several with cheezy rv crimp fittings leaking and number two being an internal pump leak. My 17 year old pump started doing it and hasn't done it again since replacing it. Maybe someone else knows about the air gap in the tank because I'm pretty sure I've seen it mentioned on here.

    Out of curiosity I have tested a few different rigs by running the pump and shutting it off and turning it back on weeks later without the pump kicking on. That's a good tight system.

    One of my first TT was a pristine Jayco which had the water pump start randomly kicking on and it ended up being a hose crimp fitting at the water heater under the bed. It started to stain the water heater and the carpet but didn't soak the wood. My sons TT started doing it and I told him he better find it and it ended up being a hose crimp fitting in his basement near the filter and it started lifting the linoleum. I'd never ignore a pump randomly turning on.

    It could be an internal pump leak and that would be a good thing compared to it actually being a leak which starts doing very bad damage. It's all about knowing which one is actually happening and it may be expensive finding out.
  • You might check for an inline filter screen right at the pump. Ours has one that can be disassembled. Every so often it gets some gunk in it and needs a cleaning.
  • Thanks everyone for the response and great information. I appreciate it.
  • Regarding a 'short cycle' once in a while... it will even do that as the water heater cools down and the pressure in the tank drops (ever so slightly) as the water cools / contracts. Nothing to worry about.
  • TechWriter wrote:
    We carry a spare pump . . . just in case.


    One of the many spares I carry. Mine has served well for 9 years & pumped thousands of gallons. Believe I would trust an unused pump less than one that has had constant use over 1500 road nights.
  • If it has been unused for ten years, I would do a sterilization first. It has probably had water in the system at some time and what remained can grow stuff. One good cleaning should do it. If you are on a city water system, then there is enough residual chlorine to keep it good.

    Matt
  • Try it out and see if it works well before leaving.

    If it works, and doesn't cycle on and off when turned on but no water is being consumed, you've done about all the maintenance that could be expected. If it doesn't work, fix or replace it. Fixing might be as simple as disassembly and cleaning.

    I wouldn't worry if it does cycle on for a second or three once in a great while when not using water, say a couple times an hour or less frequently. That would mean a teeny bit of water is leaking back through the internal check valve in the pump, typically because there's a tiny speck of dirt or grit keeping it from sealing perfectly. Sometimes that will correct itself, but even if not, there's no real harm being done. (It could also be due to a drip or slow leak somewhere else in the water system, but I assume you'd probably have discovered any such already.)
  • Put water in it and use it some. Not just one time but run some water through it. When the pump is turned on and all the air has been bled from the lines you shouldn't hear the pump turning on momentarily when a faucet hasn't been opened. If you do hear it turn on for just a second or two it may have a leak in the system or an internal leak in the pump. Mine lasted 17 years.
  • I don't think there's any maintenance. I've done nothing to mine in 10 years runs great. Put water in the tank and run it, I'll bet it's good to go.

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