Water Heater - Tongue-Mounted

The camper did not come with a water heater, and while it was easy to heat water on the stove or in an electric pot, it would be more convenient to have hot water available from the faucet. Convenient, yes ... but a real challenge to figure out!

Prepping the WH

A 2.5 gal "point-of-use" water heater from Home Depot was just right - about the same size as a 20# propane tank. It had a drain, an adjustable thermostat, and an electrical plug. The water inlet and outlet were female pipe threads in the top of the WH; I put a 1/2" male pipe (MIP) x female pipe (FIP) elbow in each one. On the inlet side, I added a 1/2" MIP x 3/8" compression adapter, and on the outlet side I added a 1/2" MIP x male garden hose adapter. That was the hardest part of the whole project - getting those connections watertight! I worked in the basement and used our washer hoses to test the connections. It took 3-4 turns of Teflon tape on the male ends (wrapped in the direction of the threads) and a lot of muscle with the pipe wrench before they were sealed. I bought a standard PVC pressure-relief valve pipe, cut it to reach to the edge of the WH, added an ebow and another piece of pipe to reach the bottom of the heater. The arrangement was awkward and fragile, so I replaced the downward pipe with a piece of large heat-shrink tubing. The tubing wouldn't get caught like the pipe did, and vented water would still be directed to the ground.

Mounting

To mount the WH on the tongue, I ha to move our single propane tank to one side. It was originally secured through cross braces with 2 threaded rods. I drilled a new hole in the cross-brace for the inner rod, but the outer rod now hung slightly over the side of the tongue. A galvanized 2x4 hanger just fit up under the tongue and the flange gave me the fastening hole I needed. The rod wasn't quite long enough to reach, but I was able to extend it with two rod-extender nuts and more threaded rod from Lowe's. I then tightened the longer rod with a wing nut  under the 2x4 hanger. The WH sat on a Lynx leveling block that just fit the space next to the propane tank (plywood would work, too) with a piece of non-skid shelf pad on the Lynx block. Two rubber bungees criss-cross over the WH, hooked to the tongue, making it secure tor travel. Since none of this was permanent, we could leave the WH at home and move the propane tank back to its original position.

Electric Connection

From the outlet behind the refrigerator, I added an appliance (A/C) extension cord which I wired to an outlet on the dinette side of the refrigerator cabinet. I used another appliance extension cord to connect the WH to that outlet. We stored the second extension cord in the battery cabinet, and simply pulled it through the old battery vent hole (see Electrical Mods) to the WH. Since the WH was on the same circuit a the sink-cabinet outlet, it was a simple matter to pull the inside plug when we used the sink outlet for another heating appliance, such as a coffee maker or electric kettle. No need to reset a thrown breaker!

Cover

The propane tank and WH were both protected with a zippered vinyl double tank cover in polar white. I replaced the original propane hose with one long enough to go under the cover to the regulator.

Water Lines

Getting cold water to the WH was the easy part. I used a brass Y with a male leg connected to the water inlet in the side of the camper. The female end of the Y aepted the campground water hose, and the other male leg connected to a 10' reinforced 1/2" hose with a barbed female hose adapter on one end, and a barbed 3/8" female compression adapter on the other. The compression end of the 10' hose was screwed to the 1/2" FIP end of a 2' braided stainless steel faucet supply with a 3/8" compression fitting that was fastened to the WH inlet compression adapter. The 10' hose was the only water line we needed to connect when setting up the camper. The 2' supply stayed with the WH and a male nylon screw cap to keep it clean during travel. 

Getting hot water inside the camper was a lot more complicated. To run through the camper frame instead of under it, I took advantage of an existing hole near the propane line. I used a hex male-hose x 1/2" MIP fitting (which fit through the hole) and an O-ring on the front side of the frame, screwed it to another hex male-hose x 1/2" FIP fitting on the back side, then wrenched them together. That gave me a secure connection through the frame, with male hose threads on both sides. From the WH outlet, I connected a 3' braided stainless-steel washer hose to the fitting on the front of the frame. A 4' hose was connected on the backside of the frame, fastened with cable ties to the propane line under the camper.

I didn't want to drill a new hole in the camper, so I removed the plastic drain cap and used the existing floor hold behind the fridge. An inexpensive camper water-inlet fit there - just barely. I drilled a few small holes around the edge of the inlet plate to maintain some drain. Because the fridge fittings forced me to set the inlet off-center in the floor hole, I could screw only one side of the plate to the camper bottom. On the other side of the plate, I used a longer screw into a piece of scrap wood set o the floor across the hole. With both screws tightened, and the outer edge of the plate caulked, the inlet was secure. The outside of the inlet had female hose threads to which I attached a male-to-male hose adapter for the female end of the under-camper washer hose. The inside inlet threads were 1/2" FIP to which I added

an adapter for the 3/8" compression end of a 12" braided stainless faucet supply. The other end of the short supply was connected with am MIP x MIP adapter to the FIP end of a 30" dishwasher supply. (Note: I had to connect 2 supplies because no one makes a 42" supply. My other choice would have been to cut a 60" dishwasher supply to the right length and use a barbed fitting for the inlet in the floor.)

The compression end of the 30" supply was threaded through an existing electric-wire hole in the fridge wall (which I enlarged a bit, after digging out the foam insulation), behind the furnace at the level of the wheel well, and into the sink cabinet. It  connected with a 90-degree compression adapter to a barbed PEX adapter on the bypass valve under the sink. It sounds a lot more complicated than it really was - everything went together beautifully. What a treat it was to have running hot water!