When I am hooked up to the campground water supply my fresh water tank fills up. How can I correct this problem? Thanks! —George B.
When the city water pressure feeds fresh water into the on-board fresh water tank it means one of two things: either a “quick fill” valve is left open (or is faulty), or the check valve in the outlet side of the water pump has failed.
If your coach is equipped with such a quick fill valve (one that allows the fresh tank to be filled while connected to city pressure), it may have failed even if it is in the “off” position.
But it could also be that the backflow preventer (check valve), positioned at or near the outlet side of the water pump has failed. Though rare, this does happen from time to time. In most cases, this check valve is integral to the pump. (Note: A few RV pumps do not have this check valve as an internal component.)
It’s not necessary to replace the complete pump. Simply add an aftermarket, in-line check valve to the outlet fitting of the pump and leave the defective one in the pump if it cannot be removed. If it’s stuck in the open position it will still allow water flow and the new, in-line check valve will prohibit the city water pressure from back-filling the tank. Simple fix!