Replace Atwood Water Heater

[Harve]

I have undertaken the big job of replacing my Atwood EHM4 hot water heater. Mine just doesn't work any more. I purchased one from Amazon for about $235 plus shipping. First off, the replacement is not exactly like the original one in my 2001 HD. The new one came with a spigot for one of the drain locations. OK, I will be abandon one of the drain lines that dumps directly to the outside. Now, I will drain with a garden hose attached to the spigot.


Some things I've learned that I will share:


1. Take a deep breath because it looks daunting at first (and it is) but you can tackle this if you take your time. It is in a very cramped space and the unit isn't really designed for the Rialta. It IS a marine water heater and is designed for a boat.


2. You will need to make cuts in various existing water supply and drain lines to get the water heater out. These lines are 1/2" (nominal) PEX lines. You can buy everything you need at Lowes or Home Depot in the plumbing department.


3. The existing system of elbow joints and in-line connectors is "old school" and difficult to work with. There is easier stuff to use and it is a "compression" system. Push the tube in the end of the connector and slide the lock ring. Voila, you're done.


4. Invest in a PEX cutter and a saw for tight spaces. You'll need to make some cuts in very tight spaces to get the old hot water out and reinstall the connections.


I'll keep you posted on other things that I learn about this install.


As an aside, I discovered that the motor heat hot water line had a leak. Basically this is loop that runs from the engine and goes through the hot water heater. This is water and anti-freeze that runs from the engine. The heat from this tube runs through the hot water heater and you get hot water as soon as you pull into your campsite. I will replace the hose (looks like a piece of radiator hose) and the clamps. BTW, this piping makes a pass through the heat exchanger underneath the wardrobe to provide heat in the back portion of the coach.


I'm also replacing the hot water switch and will keep you posted on how that goes.

[bigdan]

thanks a lot for the nice " how to "


very useful !


Dan

[Harve]

There has been discussion in the past regarding the "dreaded" red reset button on the Atwood Water Heater for the Rialta. The difficulty arises when the water temperature exceeds the preset it will shut-off requiring a very arduous ordeal to gain access to the reset button. If you want to undertake the replacement of this "ECO" (emergency cut-off in Atwood speak), you can purchase Atwood part #90037 ($13.95). You can find it at Amazon.


If you choose to replace your water heater as I've done, the updated versions sold by Atwood already have this new combination thermostat/limit switch (ECO) on them. Voila, no more red reset button to deal with.


The replacement of the water heater is slow going because of the slight modifications that Atwood has done on their newer model. As a result, the Winnebago plumbing doesn't quite line up. For example, the new model comes with a spigot to drain the tank. You can now use a garden hose hook-up and run the line outside of the RV to drain if you wish.

[bigdan]

Thanks ,


I might have to work on mine….my friend who slept in the Rialta at new year eve , accidently put the switch "on" ….(hivernized)


I should test it with an ohmeter today ….


maybe only the reset went off…ill see



If I have to replace the whole unit ill get the same that you bought , the drainis a great improvement !



Dan

[Harve]

Dan,


I've worked on this for nearly a week to get all of the connections sorted out. There are many plumbing connection challenges. I have had coolant leaks at the water heater and I now understand why. The hose fittings weren't adequately clamped and the hoses themselves weren't long enough to get a good fit.



The spigot on the new model goes off at a strange angle making difficult to connect to the drain line. It makes connecting to the hot water inlet on the water heater just above the spigot difficult to connect as well. Another complication is the existing water drain valves (that go through the floorboard) and the tubing that must connect to the spigot and to the hot water line.



It's a big job... and I thought I was going to give this to Camping World to install. They would have given up on this one. This is like 3 dimensional chess playing. The good news that tomorrow I hope to get the unit in place and make all of the final connections. I will test the water lines when we have a day above freezing here in Atlanta.

[bigdan]

good luck !



give us some news about it



Dan