RV Repair Manual
for the RV Do-It-Yourselfer
The typical RV comes equipped with a medium cost demand type water pump. These pumps were adequate for the RV water supply systems of a few years ago.
For various reasons, the water supply pipes have changed in the last few years. The popular pipe material is now "pex" type tubing. This material has advantages over the materials used for the last decade or so, but does come with its own set of problems.
One is the rigidity of the tubing. It is much "harder" than previous tubing and tends to 'chatter' more than ever. By 'chatter' I mean that it vibrates with the pulses of the water pump and creates vibrations against the floor, the walls, and the cavities within the cabinet spaces. This can result in very loud and disturbing "hammering" noise from the RV water system. One solution is to install a flexible braided hose to both the inlet and the outlet sides of the water pump. Allow enough length to include a loop in the hose so that the hose has room to move a bit to absorb the vibrations of the pump.
Another possible solution is to install sections of foam insulating material wherever the pex tubing comes in contact with the cabinets or walls. These come in tubular sections 4 feet long (available at your local building supply store) and can be cut to the needed length with a ulitity knife.
Various "fixes" can be attempted, but one of the best of all is the pump featured below.
This pump has no pressure switch, thus it creates no pulsations to bang the pipes against the walls!. It has a sensor that controls the motor speed, depending on the demand, so that the water flow and pressure is consistent. An added bonus is the lower amperage draw at low water flow levels ... an important factor for campers without hookups. So ... if you need a new water pump ... or you just can't take that hammering anymore consider the Flojet Water Pump.
Thanks go to Les Adams for this drawing: