Atwood Water heater question.

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LarsMac

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So, remember the thread I posted about racing the nasty weather and getting the RV winterized just before the cold front rolled in, back on October?
Well, it seems that I missed a very important step.
When I finally got time to look at de-winterizing, which came after I got the new Gravel/rock pad set up, I started with a gallon of water with half a cup of Bleach in the tank, turned the pump on, and began flushing the pipes of antifreeze.
All was going very well, until I decided to open up the water heater. I flipped the by-pass, and water started flowing into the heater tank. ... and then began flowing right back out, again, on to the floor underneath.
After mopping up the water, and trying to get a look at where it was coming from, it seems that the problem was that I failed to open the drain, so a small amount of water at the bottom, probably in the drain are froze, and split the weld.
Well, fine. Lesson learned. Don't forget that drain valve, ever again.

So, I get to buy a new water heater.

There seems to be a couple of options. Replace the whole unit. But WAIT, the Atwood WH that is original equipment is discontinued. I can find a couple of them online, for the wonderful bargain of just a few bucks shy of $1000.
I can find a tank for around 200-300 bucks. That looks like an adventure.
Or, a new Dometic equivalent replacement can be had for a tad under 500.

So the question? Has anyone here actually replaced a tank on a water heater? Preferably the same model? ID this actually a logical notion, or should I just by the Dometic Equivalent model, and slap it in? I've done those "Just by the parts and rebuild the thing, and save a bunch of money." things before. They usually end up costing a lit more time than the money I saved was worth.
Am I just over thinking this?
 

John From Detroit

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You are not the first to make that mistake (Short story follows)

You might want to Consider replacing ONLY the tank.. Tank comes (or at least the one I got)( comes with all the parts needed and a New 1500 watt heat element (Which I replaced with a 375 watt element more on that later) you will need a propane torch or other heavy duty heat source to "Expand" some locking rings (heat them up they get bigger).

The short story: When my Rig was brand new they dealer had a problem with the install of the tow bracket on my towed... Walking through the shop with the consultant, an insurance adjuster, and myself we passed the Insurance man's client. A busted water heater lying on the floor next to the rig I said "Forget to empty it" Consultant said "Yup". (That's the easy way to learn)

The 375 watt element
Elements are standard size physically I put in a 1500 Watt 240 volt element since W = E^2/R using that on 120 volts means 1/4 the power.. Takes a bit longer to heat the water but for me not an issue. Really cut down on breaker tripping when on a 30 amp site.
 

Gary RV_Wizard

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A little water in the tank should NOT cause freeze damage. There is plenty of room for a "little water" to expand. Are you sure it isn't a water line?

If you do need a new tank or heater, Dometic is the same as Atwood - they bought the brand and changed the name.
 

WILDEBILL308

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I think I would look for a all new efficient unit. Yes it might work to just replace the tank but then the rest is still 20+ years old.
Good luck
Bill
 

LarsMac

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A little water in the tank should NOT cause freeze damage. There is plenty of room for a "little water" to expand. Are you sure it isn't a water line?

If you do need a new tank or heater, Dometic is the same as Atwood - they bought the brand and changed the name.
the leaking only occurs when the by-pass valve is turned to allow water into the tank. I cannot get a good look at it, but it appear to be coming from where the low point drain connects to the tank.

Without removing the WH, I don't think I am going to get a good look at where the leak actually is, and probably will take that to determine what caused it.
 

LarsMac

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I think I would look for a all new efficient unit. Yes it might work to just replace the tank but then the rest is still 20+ years old.
Good luck
Bill
Good point. The newer model from Dometic is identical in cut-out dimensions, but a little deeper. I will have to modify the pipes for it to fit.
Hopefully, it lasts another 20 years.
And, more important, the price is far more reasonable.
 

JayArr

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I replaced the tank only, it was easy. You need to pull the old one out either way and you need to remove and replace the pipes on the rear either way the only place it saves you is removing the front gas valve and pilot assembly, the exhaust screen and the drain plug. My tank came with a new expansion relief valve for up top so it just screwed in. Lastly are some rings that hold the front metal cover to the tank which can be tricky but I cut a hole in a piece of wood the same diameter as the tank pipe and just tapped the ring on easy peasy.

On the rear of my tank I used some pipe to extend the connections to where they were easy to connect to the trailer plumbing.
 

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CharlesinGA

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Good point. The newer model from Dometic is identical in cut-out dimensions, but a little deeper. I will have to modify the pipes for it to fit.
Hopefully, it lasts another 20 years.
And, more important, the price is far more reasonable.
Check your dimensions again. the new Dometic model is about a quarter inch taller and about an inch and a half narrower, leaving you with a gap to fill somehow. They could have easily made the black mounting pan the same size as the original, but chose to screw things up royally for everyone. I see a good aftermarket business making a stamped metal pan (and matching door) that can be swapped onto a new Dometic to make it fit the original opening.

listen to Jay above, replacing the tank is not that hard to do. I also see it suggested to use short sections of PVC pipe the proper size to drive the metal rings in place (you need new ones). Depending on where and how it is cracked and its overall condition, it can easily be welded also.

Charles
 

LarsMac

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The new unit is deeper but the width and height appear to be identical measurements.
The plumbing shouldn't be too radical a change. I'll have to verify once the new unit arrives.
 

LarsMac

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Check your dimensions again. the new Dometic model is about a quarter inch taller and about an inch and a half narrower, leaving you with a gap to fill somehow. They could have easily made the black mounting pan the same size as the original, but chose to screw things up royally for everyone. I see a good aftermarket business making a stamped metal pan (and matching door) that can be swapped onto a new Dometic to make it fit the original opening.

listen to Jay above, replacing the tank is not that hard to do. I also see it suggested to use short sections of PVC pipe the proper size to drive the metal rings in place (you need new ones). Depending on where and how it is cracked and its overall condition, it can easily be welded also.

Charles
You are correct, I see. I should have caught that.
That will make it very inconvenient. I would be fine with putting in a unit with larger outside dimensions. but making up for a unit with smaller dimensions is a bit of a reach for my resources.
I may have to re-think replacing the tank.
In the mean time, this week's road trip will be without hot water.
 

LarsMac

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So, I've ordered the tank. We'll see how much of a PITA it turns out to be.
Have I mentioned before that I am more of a Software guy than a Hardware guy?
 

8Muddypaws

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After 45 years in programming etc. I saw the error of my ways and retired. :LOL:

I didn't find it difficult to remove the tank on my Atwood at all. The Hardest part was getting at the connections on the rear. The rest was simple.
 

LarsMac

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Well, I ended up finding the Atwood original model at a shop in Greeley area. The Dometic replacement showed up this morning, too. Still waiting on the Tank only. The Dometic refit is going back, unless I find a buyer in the next few days.

It seems that the hardest part of the task will be to get in under the sink to disconnect the plumbing in the back of the tank. I am not small enough to climb in under the sink and get to the connections with two hands. I barely can get in there with one hand.
When the tank shows up, I plan to rebuild the old one, and keep it around as a "Hot Spare"
 

LarsMac

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So, in the "Nothing is as easy as it looks" category,.., the bottom fitting, for water inflow, appears to be a plastic elbow simply screwed in to the port, unlike the top (Outflow ) fitting. So, I have to remove the hose for the inflow from the elbow. I've loosened all of the twist clamps and and none of the hoses seem to be agreeable to sliding off the fittings. I have never messed with this kind of fitting before, and am a tad cautious about breaking anything. whatever I try, I can only get into the space with one arm at a time, and I find myself in a very awkward position, unable to apply any useable force at the point where it is needed.

So, my question: Are these fittings also glued in place? Or am I simply dealing with plastic that has been in place for so long it is simply stuck and require more force to separate them? ? If the fitting on the bottom had been the same as the top, it would have been quite simple to remove those fittings and move on, but I need to pull the lower line so that I can remove that elbow, and preferably acquire a new elbow fitting just like the upper one for the new tank.
Perhaps I am making too much of it, and I should just cut the inflow line and deal with it after the fact, when I have room to work in the space without the water heater in place.
An aside. I wonder if this is how Winnebago/Itasca built the thing, or did something happen to the original fitting for the inflow, and previous owner applied a little Georgia Engineering to fix it?
From the workmanship of the rest of the vehicle, I highly suspect the latter.
 

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Gary RV_Wizard

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Not typically glued, but I have no knowledge of how Winnebago does assembly.

Plastic tubing like that gets forcably expanded as it slips over the compression fitting and then the compression nut clamps it down over the insert barb. Followed by years of aging and heat/cool cycles to make the plastic nice and brittle. It's pretty common to have to apply heat or simply cut it off to remove. If it won't budge, I'd cut it off and re-assemble with new Pex tubing.
 
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JayArr

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I agree with Gary, cut it all out and put the new tank in with Pex.

Take a look at the picture I posted above. I bought two "street elbows" and two 12" threaded pipes and two unions for the valves and connected it all up before I installed the tank, that way I only had to make two connections to the trailer and they were in a much more accessible place.
 

LarsMac

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Well, it's been a while. A lot has been going on. We got so busy that I did not have time to work on the tank. I finally had to take the Dancer in to the shop to get things done.
And thanks to Steve at Country RV in Fleming, CO, the Dancer is all happy, again.

I learned a valuable lesson. The old water heater had a petcock valve in the drain plug. That was a bad idea. The petcock valve and stem went deep enough up into the tank that it did not drain the tank as well as I expected.
So, when I though I had drained it last winter, well, there was likely a gallon or more still in the tank. and, well, ..., see pic.
A rather expensive lesson.
 

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John From Detroit

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I doubt one gallon would do much damage but.. Your evidence is hard to ignore.

I got my education on "Forgot to empty the heater when winterizing" The easy way... Somebody else forgot. I got to see the results as we walked past his rig in the service bay with the insurance adjuster. Not my heater. That's the 2nd best way (I also read about it that's the best way so when I saw it I knew what had happened) .
 

LarsMac

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So, lesson learned. The petcock, apparently had become clogged from sediment in the tank, and had never drained. (that split was in the top of the tank, BTW)
Putting a petcock in the drain plug proved to be a really bad idea, and relying on it for draining the tank was even a "more bad" idea.
 
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