RV NOW: RV Water Heater Replacement

Jim and Joy McClain have owned and enjoyed this nice Contessa motorcoach for nine years.

Jim likes to do preventative maintenance and knew his water heater was on its last legs, so he opted to replace it while he was parked by his friend Wayne Kingston who also happens to be an RV Technician. Since they purchased a pre-owned motorhome, the water heater was nine years old and they also wanted to kick up the electric power from 700 watts to around 1500 watts – more than doubling the heating capacity.

Replacing a water heater is not difficult if you have the time and inclination to do it yourself. They ordered this nice unit for around $500 clams. It is a complete unit so all you have to do is basically swap it out with the old one.

First you turn off the propane and 12 volt electric to the water heater, and unplug the unit from the 110 volt electric plug (or in many cases disconnect the romex wiring that connects the heater to 110 voltage). Then you remove the door/cover and decorative trim. Drain out the water, being careful not to burn yourself.

Next disconnect the propane connection and push the copper pipe through the hole, then emove the retaining screws on the metal frame.

Take a look at this water heater installed in a Yellowstone 5th Wheel – how is it secured?

That’s right there is a strip of plumber’s tape wrapped around it. This was the same for the water heater inside the Contessa motorcoach. The problem is that we (yes I helped) could not reach the area where the water heater was secured by the tape, so we removed the metal frame on the old water heater, broke off the surrounding Styrofoam insulation and were able to get a screwdriver in to remove the screws that were holding the plumber’s tape in place. Vice-grips make good handles when removing the old unit.

This is what the old tank looked like.

The Contessa motorcoach has flexible hoses which allow for the tank to be pulled out. Some models will require you to become a contortionist and reach around two or three obstacles in order to remove the pipe fittings.

Wayne reused the power cord, but he put new electric connectors on before reattaching it to the new unit.

Before setting the new unit into the hole, Wayne installed new elbow connectors into the back of the new tank along with a new anti-siphon valve. He treated the threads with RectorSeal 5 (a thread treatment that helps prevent leaks – other products may be used here as well – it’s a personal preference).

As a side note, the previous anti-siphon valve was not working properly and was actually restricting water flow to the point that they didn’t have hot water to the bathroom sink and they had to use the water pump as an assist to get enough water pressure to take showers. Replacing this defective anti-siphon valve solved those problems.

Set the unit up near the opening on a ladder or just have someone strong hold it there while you re-connect the 12 volt connectors, water hoses (make sure you connect the hot to hot and cold to cold), connect the 110 volt power cord and pull the feed string through the propane line opening.

Notice that Wayne is pulling the propane supply line back through the hole in the new unit with the feed string that he previously tied to it for this purpose.

Here is a picture of the propane supply pipe with the string attached.

After attaching the propane supply line to the pressure fitting (no pipe dope or Teflon tape required since it is a pressure fitting) turn the propane supply back on and test the fitting connection for leaks using a solution of soapy water.

If you see bubbles emerging from around the fitting, check to see that it is threaded correctly then tighten it some more being careful not to over-tighten the fitting.

Now turn on the electric and fire it up to make sure everything works. Secure the metal frame with a few screws and re-attach the decorative trim and cover/door.