Replacing Atwood Water Heater

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Replacing Atwood Water Heater

February 28, 2020, 08:13:06 am

Howdy Everyone!

I'd like to replace my aging (1994) Atwood Propane/Electric/Exhaust Gas water heater on my 1994 U280 40ft, and I'd love to hear from people who either have done it themselves, had it done professionally, or even just researched it. I'm within a week or so of making a purchase decision.

My requirements are that I need both propane and electric, but don't really need exhaust gas. I'm not married to a tank-based solution, so tankless suggestions are welcomed too. I'm happy to DIY if it is simple enough to do, but if it gets complicated or dangerous, I can have it professionally installed. I really don't want to do this more than once, so I want to get it right the first time.

I'd love to hear from the community :-)

Mark

Re: Replacing Atwood Water Heater

Reply #1 – February 28, 2020, 08:39:18 am

Mark, We replaced out 10 gallon heater with a 10 gallon (Attwood I think) electric/propane heater. Same size and footprint. Getting to rear facing connections via a hole in forward wall is tight but not too hard. We use the electric element most of the time and never run out of hot water. These heaters come in models that also have over the road heating by the main engine too.

The concern with tankless heaters, that I have no experience with, is enough capacity to heat the flowing water to a temp you are happy with. Some do and some do not. So research these carelfully and you will find one that makes the grade.

Re: Replacing Atwood Water Heater

Reply #2 – February 28, 2020, 09:01:32 am

Assume your water heater is also "motor-aid" so engine coolant circulates through a coil in it.

Re: Replacing Atwood Water Heater

Reply #3 – February 28, 2020, 09:02:28 am

Quote from: defendertx – February 28, 2020, 08:13:06 am

...but don't really need exhaust gas.

Can't help with your new heater choice, cuz we're still using our 27-year old original Atwood heater. Will watch the responses to your question with great interest - it's only a matter of time before we'll need a new one.

One small correction. It sounds like you think the "engine heat" (motor-aid) option is supplied by exhaust gas. Actually, it is done by circulating engine coolant around or through the water heater tank. I think it is a very nice option, but if the new water heater has both electric and propane heating elements, you could achieve the same thing (on the road heating) by connecting the 110V electric mode to a inverter powered circuit.

Here's a good look at what's involved in the replacement project:

Replacing a Water Heater

Re: Replacing Atwood Water Heater

Reply #4 – February 28, 2020, 09:03:15 am

On our 95 300 we replaced the water heater with the same Atwood model which included the engine heat feature.
jor

Re: Replacing Atwood Water Heater

Reply #5 – February 28, 2020, 09:09:47 am

I'm with Chuck,
Don't know about and never heard of an exhaust gas option.
Must be referring to MotorAide with heat exchanger.

Re: Replacing Atwood Water Heater

Reply #6 – February 28, 2020, 09:46:52 am

I replaced mine. Same footprint with the exception that the new one comes with a relay for the electric element instead of the thermistors on the back. To avoid use of the engine aid I just connected both ends of the hoses to the gate valve and keep it closed.

Re: Replacing Atwood Water Heater

Reply #7 – February 28, 2020, 10:03:15 am

All,

OK - I think it should be pretty obvious how much of a newbie I am

I said exhaust, but Bret is exactly right, I meant to say engine coolant. Yes, I have that model. And thanks for the suggestion to just bypass that feature by connecting the hoses together if I don't want to use it. I doubt it is something I would use very frequently. My model can hold 40 gallons of propane, so any time electricity is not available, I'll probably just be able to use propane.

Thanks for everyone that is commenting! I'm still collecting data.

Mark

Re: Replacing Atwood Water Heater

Reply #8 – February 28, 2020, 10:29:41 am

If you have a motor aid water heater stay with it.
When you arrive at your destination you will arrive with a tank full of free hot water.

Re: Replacing Atwood Water Heater

Reply #9 – February 28, 2020, 10:38:59 am

Quote from: defendertx – February 28, 2020, 10:03:15 am

I doubt it is something I would use very frequently.

Why would you NOT use the MotorAid feature (if you have it)? You might as well use the excess heat generated by the big engine for something besides heating the atmosphere and contributing to Global Warming. Like John says, IT IS FREE!

The second best option for heating the water going down the road would be electric (like I said above). If your batteries are fully charged, then your alternator doesn't have much to do. Might as well use it to charge the batteries (BOOST on) to power the inverter to heat the water...

Using propane to heat the water (while driving) would be my last choice. You have to pay good $ for the propane. Why "waste" it?

Re: Replacing Atwood Water Heater

Reply #10 – February 28, 2020, 10:59:47 am

Quote from: Chuck & Jeannie – February 28, 2020, 09:02:28 am

Can't help with your new heater choice, cuz we're still using our 27-year old original Atwood heater. Will watch the responses to your question with great interest - it's only a matter of time before we'll need a new one.

Here's a good look at what's involved in the replacement project:

Replacing a Water Heater

I agree with using the same unit for replacement as original.

The above link helped me immensely. This year, I replaced my original 22 year old unit with the same unit. I did so only to prevent an issue when traveling out of town where it might be difficult to change. Of course replacement does not guarantee this.

This I chose after 5+ years researching many other options and talking to others that went to different units. Sometimes simpler is better, and the original type is the best for all around use.

If you do change to the same unit, you will have to change out the switch. The unit comes with a white switch, I found this black one better matches the interior.

GAS/ELECT W/HEAT EXCHANGE, DIRECT SPARK | 80-1375 | by PPL

Repurposing the "hot water dispenser" toggle switch.

Re: Replacing Atwood Water Heater

Reply #11 – February 28, 2020, 11:19:27 am

Personally, I would not overthink this. Just get the direct replacement and save the time and aggravation of trying to make something else work

Re: Replacing Atwood Water Heater

Reply #12 – February 28, 2020, 11:47:00 am

John, Chuck & Jeannie, and Jack,

Thanks for the input. Actually I was just thinking that having the coolant connection was just one more thing to break, but, after listening to the compelling arguments, it doesn't really seem like it is a problem. Also, you all make good arguments for keeping what I have. If I think about it, the hot water heater I currently have (which is a 2E, not a 4E), HAS lasted a good long time. If a replacement lasts just a long, then it really would be a smart purchase. Plus, I wouldn't have to think about how to change the system - compatibility is built in.

Thanks for the good advice everyone!

Mark

Re: Replacing Atwood Water Heater

Reply #13 – February 28, 2020, 12:03:27 pm

Just had it done. Bought it on line for $600 to my door from United RV in Texas. Had my dealer install it. I went with gas only as the new electronic start is not compatible with the existing wiring and they would have had to run all new wiring and gas is more efficient anyway. I kept the engine water heat model

Re: Replacing Atwood Water Heater

Reply #14 – February 28, 2020, 12:47:28 pm

Quote from: dans96u295ft – February 28, 2020, 12:03:27 pm

Just had it done. Bought it on line for $600 to my door from United RV in Texas. Had my dealer install it. I went with gas only as the new electronic start is not compatible with the existing wiring and they would have had to run all new wiring and gas is more efficient anyway. I kept the engine water heat model

Dan, I'm sure for you, yours will be just fine.

For others, wiring is pretty simple. As I remember, I used mostly the preexisting wiring. Also electric is free in most parks I use. A combination of electric and gas gives you a faster recovery rate. The motor aid type water heater is just a great plus. My advice is replace like for like.

$160 more, and an hour more, at most, (that was for me completing and I had never done one before) for the rewire seems like a bargain to me to get the above features.

If you cannot wire yourself or have an experienced installer available, at least install the right replacement unit and complete the wiring later.

Re: Replacing Atwood Water Heater

Reply #15 – February 28, 2020, 12:52:11 pm

("The second best option for heating the water going down the road would be electric (like I said above). If your batteries are fully charged, then your alternator doesn't have much to do. Might as well use it to charge the batteries (BOOST on) to power the inverter to heat the water...")

Chuck, Yours must be wired different than ours, WH is not powered from the inverter. Only works on electric when on shore power or generator.

FWIW we enjoy having the Motor-aide option. Free hot water when you stop at a rest area for the night.

Re: Replacing Atwood Water Heater

Reply #16 – February 28, 2020, 01:41:36 pm

Quote from: FourTravelers – February 28, 2020, 12:52:11 pm

Chuck, Yours must be wired different than ours, WH is not powered from the inverter. Only works on electric when on shore power or generator.

No, ours now works the same as yours. But I mentioned up above in Reply #3 the possibility of wiring the electric element to a inverter powered circuit. I would consider doing that if I installed a new 2-way heater that did not have the MotorAid feature.

Re: Replacing Atwood Water Heater

Reply #17 – February 28, 2020, 02:05:18 pm

Following this with high interest, we have considered replacing our original water heater.
Just can't justify it yet, the old workhorse still heats perfectly fine, gas or motor aid (never used), no electric.

Chuck and Justin,
You guys talked me into opening the motor aid option on our next trip.
Previous owner never used it, and it appears the original owner never used it.
I "exercised" the shut off when we bought the coach now it has the occasional drip out of the stem.
After seeing the drip I envisioned catastrophic failure at a most inopportune time with hot coolant, under pressure, spewing
and flooding the compartment, me up front watching temps climb wondering ....?
It's been in the closed position since.

That said I'm opening it up.
Boy is the DW going to be surprised when we stop for the night.

Re: Replacing Atwood Water Heater

Reply #18 – February 28, 2020, 02:15:23 pm

Quote from: Phranko – February 28, 2020, 02:05:18 pm

Previous owner never used it, and it appears the original owner never used it.

Just the opposite situation here - our previous owners (all 4 of them) apparently always used it and never closed the valve. The valve looks to be original, and I would be afraid to try to close it at this point, for the same reason you mentioned. But as I said, I don't know why I would ever want to close it. I can't imagine needing more heat from the dash heater - it already puts out more than we ever use.

If you decide to open the valve, do it before you go on a trip, and have a backup plan in case it breaks or leaks. Better safe than sorry.

PS: In case you decide to install a new valve. They sell rubber hose pliers at auto parts stores. You can use them to pinch off the hoses so you can change the valve without losing a lot of coolant. Example below:

Amazon.com: Hose Clamp Pliers, 3Pcs Nylon Fuel Water Line Clamp Tool Hose...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Replacing Atwood Water Heater

Reply #19 – February 28, 2020, 02:24:02 pm

Consider using some hose pinching pliers to clamp off the heater hose on both sides of the old gate valve, and replacing it with a 1/2" brass ball valve. Get a pair of heater hose fittings from an auto parts store (or Amazon), as a regular hardware store barbed fitting will seep from time to time (that coolant is slippery!). I replaced ours with two valves in order to completely isolate the motoraide loop for removal, but using one will do the job for adding or subtracting cabin heat.
Don

Quote from: Phranko – February 28, 2020, 02:05:18 pm

Following this with high interest, we have considered replacing our original water heater.
Just can't justify it yet, the old workhorse still heats perfectly fine, gas or motor aid (never used), no electric.

Chuck and Justin,
You guys talked me into opening the motor aid option on our next trip.
Previous owner never used it, and it appears the original owner never used it.
I "exercised" the shut off when we bought the coach now it has the occasional drip out of the stem.
After seeing the drip I envisioned catastrophic failure at a most inopportune time with hot coolant, under pressure, spewing
and flooding the compartment, me up front watching temps climb wondering ....?
It's been in the closed position since.

That said I'm opening it up.
Boy is the DW going to be surprised when we stop for the night.

Re: Replacing Atwood Water Heater

Reply #20 – February 28, 2020, 09:43:02 pm

I am not a full timer and my past heaters were dual and I still used the gas option, so not a big deal to me. I may add electric later. I dry camp most the time as well

Re: Replacing Atwood Water Heater

Reply #21 – February 29, 2020, 09:05:48 am

I'm saving this thread as a pdf for my documents file. Lots of good info. My electric side of the water heater doesn't work, but I've used the motor aid and propane. Had to replace the pop off valve which had started to release water as it came up to temp. Worked fine since that replacement.

Re: Replacing Atwood Water Heater

Reply #22 – February 29, 2020, 09:15:14 am

Chuck, Don,
Good advice, I'll get started on that today.
Once I have all the parts in place we'll make a local run with the old valve open to gauge results.
Good picture Don, always helps to have a picture.

Thank You!

Re: Replacing Atwood Water Heater

Reply #23 – February 29, 2020, 10:45:49 am

Getting the trim off was the worst part of the entire job. Drilled pop rivets, etc. They charged me 3 hours labor but didn't wire in the electric. The tech didn't seem confident in that area and their service manager had just retired for help so, I didn't want him experimenting on my MH. Later and after all this info, I'll get it wired up
Thanks

Re: Replacing Atwood Water Heater

Reply #24 – February 29, 2020, 03:39:16 pm

Howdy Everyone!

Its the weekend, and I'm working on the RV :-)

OK, silly question: As you know, I have a GCH10A-2E. This means gas, electric, and engine coolant modes. Is there a way to "force" it into electric mode? I've read through the documentation and don't see anything about that condition. I've turned the propane "off", so there is no gas getting to the water heater. Now, what I want to do is "force" it to try heading with electricity. I assumed, maybe incorrectly, that merely turning off the propane would cause the water heater to sense that it would not light, and then try electricity next. But, I'm not really sure about it. RV is powered by a 50 Amp circuit, and all other electrical devices are working. Anyone have any insight?

Thanks!

Mark

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