Saturday, December 3, 2022


Water pump doesn’t pump


The RV Doctor

Dear Gary,
I’m having my RV winterized for storage. The dealer called to tell me that the pump doesn’t work. It is located underneath the fresh water holding tank. They unhooked it from the tank to pump antifreeze into the pipes and it wouldn’t work. Is it a suction pump? Does it have to be connected to the holding tank to work? —Walter

Dear Walter,
It’s not uncommon to disconnect the water pump from the fresh water tank in order to pump the RV antifreeze through the system. A better setup, however, would be a tee in the suction line between the pump and the fresh tank with a dedicated shut-off valve just for the winterizing purpose. This is easily added.

water-pump-rv-doc-rvt766RV water pumps are self-priming pumps, but on rare occasions they can develop an air blockage. When they told you the pump didn’t work, do they mean it runs, but does not pump? Or does the motor not run at all? If it does not run at all, it is probably a 12-volt DC electrical issue and not a priming problem. But if the power and ground connection is correct, it then may be necessary to “prime” the pump by pouring water directly into the inlet hose connected to the pump.

RV water pumps do “suck” the water out of the fresh water tank and they also “push” the water through the rest of the fresh water system whenever there is a demand for water. If an air bubble exists on either side of the pump, suction or downstream, it could cause a water flow issue. Further investigation may be in order here.

Read more from Gary Bunzer at the RV Doctor.  See Gary’s videos about RV repair and maintenance.

##RVT766 ##RVDT1240

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Joe Foster
2 years ago

A general question: In my Tiffin Allegro I have a lot of storage space under my RV. Several compartments have pass-thru spaces that are 10-12″ high. My storage boxes for this area won’t stay where the should. After a travel day I’ll open a compartment to find the storage boxes from the upper storage area have shifted and next to the compartment door.
I’ve tried velcro but this makes removal and replacement difficult. Any suggestions would be appreciated.

6 years ago

If the pump runs but no water moves, try sucking on the end of an open faucet with the pump on. If it starts to work you’ve removed the air pocket. On the other hand, if the dealer really completely diagnosed the pump as a failed unit, it’s probably just that.

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