LP Hot Water Heater Protocol

Let’s talk LP Hot Water Heater.

Since we have an Dometic Atwood Propane Water Heater – that will be the focus of this blog post. In other words I don’t have a dual electric/propane water heater. Also ours has an aluminium tank which does not require a sacrificial anode rod to keep a “steel tank” from rotting away.

I guess we just have a simple, turn the switch on and presto “hot water” in 10 minutes or so. Never-the less, the maintenance protocol would be similar to all of the different types of water heaters.

At the end of our camping season we must winterise Blue Streak, which I would imagine is the same for lots of folks. I would also recommend that those who are fortunate to travel year around do the following maintenance protocol at least once a year to make sure all is well (cold showers suck in my opinion).

Each fall we drain the water system completely (I have an entire blog post on winterizing Blue Streak here). The hot water tank requires a bit of care. First, make sure the hot water tank by-pass is on. This is to avoid anti-freeze going in the tank if you use it (which we do). Two reason to avoid this 1) the tank holds 6 gallons (27 litres) which would take a LOT OF ANTI-FREEZE, 2) it tastes yucky (a technical term).

Next, open the outside access cover to the hot water tank and find the drain plug. I should mention that the hot water tank SHOULD NOT BE HOT.  If you have to ask why? – then I recommend you have a dealer do this for you (just saying).

Typically the plug gets removed once a year, during winterising, to drain the water heater. It’s made of nylon (usually white in colour), because nylon won’t react with the metal in the tank which can result in corrosion.

Because the nylon is soft and easily damaged, it should be replaced with a fresh one every time it is removed. These plugs are NOT cheap on Amazon or at your local RV supply store. However, I found that at my local hardware store a 1/2″ NPT plastic drain plug with 15/16″ head costs about a $1.00. Get a few spares while you’re at it, saves a trip.

Heads Up! you’re going to ask: “How the @#%$ do I get this plug out?!?!”

Yep, it’s not conveniently located on RV water heaters, in fact I think it was design this way to drive us crazy..The number one thing is not to try to get at the plug with an adjustable wrench, it does not work!

You’re going to need three simple tools:

  1. a 15/16″ socket
  2. a ratchet wrench with a drive size that fits the 15/16″ socket (usually 1/2″ drive)
  3. an extension of 5-10″ length in the same drive size (mine has a swivel)

These are some tools you should carry in your tool box/bag in any event.

Once you have them all connected and on the drain plug – remember what my dad taught me: righty-tighty, lefty-loosey. OH! by the way be prepared for a gush of water as the plug comes out.

  1. Don’t stand directly in front of the plug (remember water is wet).
  2. You may need a bucket on the ground below the water heater (remember 6 gallons).
  3. Throw away the old plug so you’re not tempted to reuse it someday.

By the way, if you flick open the pressure release valve the water will come out faster.

Once the tank has drain you’re now going to have to do the maintenance (after all that’s why we’re here).

For this you’re going to require a hose connected to water and a Camco RV (or similar) hot water tank rinse wand (get it on Amazon). Use this to rinse out all the crud you will find in the bottom of your tank (also mineral deposits which are flaky white particles). Once you spent time doing this (personal judgement). The next step is highly recommended but, well it depends, it is in fact required if your water has a high mineral content (usually referred to as “hard water”).

This next step is a “white vinegar rinse”. I found an easy and effective way to do this. You will need some PVC pipe and fittings to make it happen. (see picture)

  • 3/4″ x 24″ inch PVC pipe
  • 3/4″ x 3/4″ Elbow connector
  • 1/2″ threaded to 3/4″ pipe connector
  • and a funnel

Screw the 1/2″ threaded connecter into the drain hole and the hand fit the elbow to the connector then the pipe and the funnel on top! No need to glue just hand assemble works great.

Now you will required to pour in 3 gallons of white vinegar and topped it up with water until it begins to drain out of the open pressure release valve. It works best if allowed to sit over night. Next morning simply turn to assemble to the left and drain into a bucket. After draining, take the PVC assemble apart and store it away for next year. Take the Camco Rinse Wand and rinse out any crud in the tank.

Installing the new replacement plug is just as easy, with one extra step. Have some plumber’s tape (aka White Teflon tape) on hand to wrap 3 or 4 turns tightly around the threads of the new plug before you begin to thread it in. This is important because once the how water tank in pressurized it may leak from the drain if you don’t do this.  What happens if there is a slow leak? (you ask?) The tank begins to loose pressure, which in turn will cause your water pump to cycle! (Oh, so that’s why it happens and I can’t find a leak any where – you say!)

Begin by screwing the plug by hand, to make sure it’s not cross-threaded. You should be able to give it a turn or two with your fingers. Once you’re sure it is going in straight you can switch to the tools to finish tightening it. Don’t forget to close the pressure release valve.

Once this is accomplished, open the by-pass valve and and fill the water tank. I find that this is best accomplished by connecting to the city water inlet rather than using the water + pump from the trailer’s fresh water tank. Open all the taps in the trailer to flush and then pressurize the system. Check for leaks – you’re done!?

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