Atwood Water Heater Replacement Success Tips

[Audidog]

Here are some things that I did not find in the YouTube videos or forum discussion searches I encountered in the removal and replacement of my 10 gallon Atwood water heater on my 2008 Diplomat 40 PDQ.
The access to the heater rear is through a small black plastic door in the storage bay just right of the heater. The door is just behind the vacuum at the top of the wall. With a flashlight you will see a power cord plugged into a receptacle on the ceiling of the heater bay and there is a cable clamp screwed into the back wall of the heater bay that you must remove. You will see the pex piping for the cold (blue) and hot (red) water lines. The plumbing lines interfere with easy access to remove the lines from the tank but can be pushed around enough to get channel locks on the connectors to unscrew them. Mine were not removable by hand and needed channel locks to unscrew.
The heater front not only involves removal of a door but also a trim piece that you set aside to not get scratched. The new heater comes with a new white door and wall switch neither of which were used.
Once removed you will see that the back of the heater has the bypass valve and fittings that must be removed and transferred to the new heater. I used a 1 inch and 15/16 inch wrench to remove the fittings. You must cut the 7¼ inch long ½ inch red PEX pipe connecting the bottom tank port to the top tank port in order to remove the fittings. Minimum purchase of PEX pipe is 5 feet so you will have plenty left over pipe. I rented a PEX clamp crimp tool ($12 for 4 hours) and used pro circle clamps. There were pinch clamps used for original installation and they are a bear to remove without removal tool but can be done with small screwdriver and prying. Only poked one hole into my hand with this removal technique so be careful.
The power plug must be removed and reused. Twist connectors are found inside the black plastic square cover you will see on the tank rear. The wiring connector on the original tank must be reused so give yourself some wire length from the connector to splice (18 AWG) to the new tank wires. All wire colors match so straight forward on the splicing.
Gas line has a grommet and I had to use old grommet since new grommet would not fit over gas line fitting connector.
Had I known these things above would have saved me a lot of time. I was on a learn-as-you-go process so it took me most of the day to do this removal/installation and test everything upon completion. Hope some of the above helps someone getting ready to swap out their water heater.

[broadrun]

Originally Posted by Audidog

Here are some things that I did not find in the YouTube videos or forum discussion searches I encountered in the removal and replacement of my 10 gallon Atwood water heater on my 2008 Diplomat 40 PDQ.
The access to the heater rear is through a small black plastic door in the storage bay just right of the heater. The door is just behind the vacuum at the top of the wall. With a flashlight you will see a power cord plugged into a receptacle on the ceiling of the heater bay and there is a cable clamp screwed into the back wall of the heater bay that you must remove. You will see the pex piping for the cold (blue) and hot (red) water lines. The plumbing lines interfere with easy access to remove the lines from the tank but can be pushed around enough to get channel locks on the connectors to unscrew them. Mine were not removable by hand and needed channel locks to unscrew.
The heater front not only involves removal of a door but also a trim piece that you set aside to not get scratched. The new heater comes with a new white door and wall switch neither of which were used.
Once removed you will see that the back of the heater has the bypass valve and fittings that must be removed and transferred to the new heater. I used a 1 inch and 15/16 inch wrench to remove the fittings. You must cut the 7¼ inch long ½ inch red PEX pipe connecting the bottom tank port to the top tank port in order to remove the fittings. Minimum purchase of PEX pipe is 5 feet so you will have plenty left over pipe. I rented a PEX clamp crimp tool ($12 for 4 hours) and used pro circle clamps. There were pinch clamps used for original installation and they are a bear to remove without removal tool but can be done with small screwdriver and prying. Only poked one hole into my hand with this removal technique so be careful.
The power plug must be removed and reused. Twist connectors are found inside the black plastic square cover you will see on the tank rear. The wiring connector on the original tank must be reused so give yourself some wire length from the connector to splice (18 AWG) to the new tank wires. All wire colors match so straight forward on the splicing.
Gas line has a grommet and I had to use old grommet since new grommet would not fit over gas line fitting connector.
Had I known these things above would have saved me a lot of time. I was on a learn-as-you-go process so it took me most of the day to do this removal/installation and test everything upon completion. Hope some of the above helps someone getting ready to swap out their water heater.

Great write-up! Thanks for sharing. Your timing couldn't have been better for me. My tank cracked over the winter (forgot to drain) and I've decided to just replace the entire unit as opposed to ordering a new tank only.

Which unit did you order? I'm assuming that they manufactured these things to be able to fit into most all MH's. I had enough sense this time (rarely occurs with me) to save all the old fittings and I even removed the power cord just in case. I'm not going to replace it right away because we only use our MH in the summer in northern Michigan and you can't beat the lake for washing up. We've only ever used the shower once before...

Having said that, I do want to replace it at some point so I'll print out your post for future use.

Thanks again.

[Audidog]

I ordered the GC10A-4E. Shop around because I found the prices vary considerably from under $600 to above $900.00.

[broadrun]

Thanks. That's the one I'd be installing as well. I had the GC10A-3E but they don't make it anymore. I may have to tweak my wiring to make it work but I'm sure it'll work out.

[Old-Biscuit]

Originally Posted by broadrun

Thanks. That's the one I'd be installing as well. I had the GC10A-3E but they don't make it anymore. I may have to tweak my wiring to make it work but I'm sure it'll work out.

YES you WILL need to redo/add some wiring........different control schemes
2004 Atwood changed to a DC Control for both AC element and Propane so both use the circuit board for control and just one set of t-stats etc

Here is manual that will help with the 'conversion'
See pgs 23,24, 25
http://www.atwoodmobile.com/dealer-m...aterManual.pdf



Audidog
Just curious why you had to replace your water heater??

[Audidog]

I replaced it because it quit working on AC power. It wouldn't work on propane as well. I did the easy stuff like flush out tank and check to see if it had power but nothing obvious appeared to be the problem with it not working. My RV is 10 years old now and previous life was a showcase for a large company and was not used for living or camping that much. The water heater more than likely sat idle and did not get flushed out very often because the deposits that came out of it when I emptied the tank would have filled a 1/2 cup. It also had signs of considerable oxidation and rust. I'm sure it could be repaired by changing out the non-working components but I have limited time so the best option for me was to put a new one in. If someone is interested in my old unit let me know and we can get it to you if you pay shipping. I would hate to throw it away but will not be keeping it for parts. Hopefully the new one will last 10 years.

[Old-Biscuit]

Originally Posted by Audidog

I replaced it because it quit working on AC power. It wouldn't work on propane as well. I did the easy stuff like flush out tank and check to see if it had power but nothing obvious appeared to be the problem with it not working. My RV is 10 years old now and previous life was a showcase for a large company and was not used for living or camping that much. The water heater more than likely sat idle and did not get flushed out very often because the deposits that came out of it when I emptied the tank would have filled a 1/2 cup. It also had signs of considerable oxidation and rust. I'm sure it could be repaired by changing out the non-working components but I have limited time so the best option for me was to put a new one in. If someone is interested in my old unit let me know and we can get it to you if you pay shipping. I would hate to throw it away but will not be keeping it for parts. Hopefully the new one will last 10 years.

Not working on AC or Propane......
Sounds like lack of DC Power issue
DC is common for both heating sources

Also sounds like it would be a good replacement for someone.
10 year old Atwood still has many years of use left.

Maybe someone will take you up on the offer........

[broadrun]

Originally Posted by Old-Biscuit

YES you WILL need to redo/add some wiring........different control schemes
2004 Atwood changed to a DC Control for both AC element and Propane so both use the circuit board for control and just one set of t-stats etc

Here is manual that will help with the 'conversion'
See pgs 23,24, 25
http://www.atwoodmobile.com/dealer-m...aterManual.pdf



Audidog
Just curious why you had to replace your water heater??

Thanks Biscuit.

[broadrun]

One last question:

Since I've already discarded my old unit (3E), is there any reason not to install a tankless (on demand) water heater? Interested in hearing pros/cons.

[broadrun]

Originally Posted by broadrun

One last question:

Since I've already discarded my old unit (3E), is there any reason not to install a tankless (on demand) water heater? Interested in hearing pros/cons.

So, circling back to this thread. Seems I got no response to my last question about tankless water heaters. I still haven't replaced my hot water tank because, as I mentioned a few years ago, we rarely have a need for it.

Now, as I'm getting closer to retirement, no doubt I'll need to fix it sooner rather than later.

Seems like a tankless hot water heater would be the perfect solution for an RV but I've never worked with the so I have no idea.

[Old-Biscuit]

Tankless water heaters CAN be swapped........just pay attention to the water supply/power needs of ANY tankless you consider to use


Constant...consistant water supply FLOW is needed for sucessiful operation


Standard RV water heater fits/works without much fuss....IMHO

[broadrun]

Originally Posted by Old-Biscuit

Tankless water heaters CAN be swapped........just pay attention to the water supply/power needs of ANY tankless you consider to use


Constant...consistant water supply FLOW is needed for sucessiful operation


Standard RV water heater fits/works without much fuss....IMHO

Thanks Biscuit.

[broadrun]

One more thing:

Does anyone know if Atwood (Dometic) still makes the hot water heaters that still have the heat exchange feature where it heats the water with engine coolant flow through the tank?

On the Dometic Website they list the GC10A-E but not the GCH10A-E with the letters meaning:

G = GAS
C = Combo Gas/Electric
H = Heat Exchange...

Maybe there were mishaps with a cracked tank allowing coolant to spill into the coach and they discontinued it.

Just curious.

[Old-Biscuit]

Atwood GCH10A-4E on sale for $600
https://parts.unitedrv.com/products/...xchanger-94023