Hot Water Tank replacement...

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Alaskan
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Hot Water Tank replacement...

Post by Alaskan »

Recently did a tank only replacement....they refer to it as a re-line

Note... This job is much much easier if you remove the floor section above the hot water tank in the hanging closet...!

Atwood Part # 91642 (GH6-4E)

Re-line $150 vs. complete replacement $450/$600 plus depending on the type of ignition you choose...

The re-liner kit consists of a new aluminum tank, now with a styrafoam insulation box, a new brass safety pop-off valve and 2 new steel rings that hold the pan to the tank...

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The flame enters the bottom there on the right and exits at the top left...these are the 2 fittings where the rings fit over to hold the pan to the tank....these are All that holds those 2 main sections together..

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These retainer rings hold the face-plate to the tank itself..

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Rear view of replacement tank with the styrafoam container...(you will not be using that tube assemble)

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New safety pop-off valve & new temperature control units..

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The card there (above) doesn't come in the kit...these are the 2 temp control units, one turns the tank on when the temp drops to a certain point and of coarse the other turns the flame off when the temp reaches a pre-set temperature .... as one of mine had a damaged electrical terminal I replaced them...$12.00 Atwood 91447 (DSI/TSTAT&ECO Service Kit)

Our hot water tanks don't last forever as they are aluminum. Corrosion or electrolysis will eventually get to them and they will begin to leak, usually you will see evidence of this first on the back of the tank as the cardboard covering will show stains or you'll see water on the floor of that compartment.

Its important to have an anode (zink) in our drain plug to prevent electrolysis...which eats holes in the aluminum tank over time...

So.....you can buy a complete new unit at about $450/$600 or you can do a re-line as the rest of the pieces don't wear out...

Removing the unit is very easy, 2 water lines on the back, propane line in the front (be sure to turn your propane tank valve OFF) and 20 screws outside and the unit slides right out.....as you slide the unit out you'll be able to disconnect the wiring.

Once removed the next step is to remove that front pan from the aluminum tank itself.

Remove the brass safety valve...you won't be re-using it as the re-line kits comes with a new one. Next remove the exhaust shielding.

You'll now see 2 round aluminum pieces about 2 1/2" in diameter, one at 11 o'clock and the other at 5 o'clock, these are actually part of the aluminum tank....around these 2 pieces you'll see a steel ring. These rings need to be removed, best done by cutting them with a dremel tool...once these two rings are removed you can separate the face plate (called a pan) from the aluminum tank....the hard part is behind you. The reline kit provides you with new replacement rings..

I made a little tool from a piece of aluminum tubing to use to install the new retainer rings on straight..

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Unit removed from Airstream...

NOTE... water input shut-off ball valve now installed, red handle)

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Ready to be installed back into its compartment...

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A replacement tank has an option that the old unit didn't have, and because our hot water tanks are located at the rear you wouldn't consider
using that option.

There is a tube here (below) that would also allow you to run water hoses to the unit that would include the hot water heater into your vehicles cooling system as another way to heat the water or to keep it while while traveling...
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This is the front pan when separated from the aluminum tank...

This is the ORIGINAL front pan....

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Made a little tool from a piece of aluminum tube to help install those steel rings straight and get them in tight against the pan...

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Here is a closer view of the steel ring that holds the pan into the tank...down there in the lower right where the flame enters the tank, the other ring is behind the exhaust shield up in the opposite corner...

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One of the 2 retainer ring at lower right..and the other would be behind the black exhaust cover at upper left...very easy to install, especially with a piece of tubing the correct size to use as a driver.

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Here is a better picture of the tank itself. The steel rings fit tightly over those 2 welded fitting on the tank..

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Last edited by Alaskan on Fri Sep 04, 2009 1:18 am, edited 13 times in total.
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skater
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Post by skater »

Good writeup. Did you put a water heater bypass on it for winterizing?

Also...heat with the engine's coolant? Aye carumba, that seems fraught with dangers. Let's see...running 40+ feet of coolant hose from the engine to the water heater...wow. Plus it'll cool off a good bit, I'd think, by the time it gets to the water heater.
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Post by Alaskan »

skater wrote:Good writeup. Did you put a water heater bypass on it for winterizing?

RJ....there is a dump valve that empties the tank directly onto the ground for winterizing if thats what you're referring to, thats been there as Airstream installed that...Iam sure yours has that

But...in re-doing all this I did install a shut-off valve on the input line to the tank so I can have the system active but not have water in the hot water tank...maybe thats what you meant


Also...heat with the engine's coolant? Aye carumba, that seems fraught with dangers. Let's see...running 40+ feet of coolant hose from the engine to the water heater...wow. Plus it'll cool off a good bit, I'd think, by the time it gets to the water heater.

ya....its NOT an option for us but in some applications it might well be...its very common on boats to include the hot water tank in the system...that would include the hot water tank in the system much like your cars heater

if you look you can see where the lines would hook up on the back of the hot water tank...only as a supplement to keeping the water warm/hot...obviously the closer the hot water tank is to the vehicles engine the more efficient that would be...and they make an insulation for the water hoses so they retain the temperature...
RJ....look at the 4th picture, I made a notation for ya.... :lol:
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Post by Alaskan »

I also installed a ball-type shut-off valve (red handle) so I could prevent the hot water tank from filling if I don't care to have it full at times.....

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Top view...tank drain for winterizing there at right with exit out through floor...

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Last edited by Alaskan on Fri Sep 04, 2009 1:13 am, edited 2 times in total.
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Post by skater »

No, the water heater bypass is used to let you fill the system with antifreeze (drinkable variety, of course) without filling the water heater.
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Post by Alaskan »

yep....my ball valve would allow you to do just that, but I wouldn't

It much easier to just remove all the water with the dump valves installed by Airstream and a little air pressure...

If you look in your Airstream B190 Owners Manual it says you're supposed to head to warmer climates in the winters rather than use that drinkable anti-freeze..... :lol:
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Waterheater Replacement

Post by craigmar »

Well we took the van to a small ceremony honoring WW II vets which my father in law is (B-17 pilot) and upon turning on the water pump so the grand kids could use the toilet, we discovered a huge leak coming from the water heater, specifically, around the pressure releif valve. After tearing the cardboard and insulation away from the tank there were no other problems found so I am going to do the re-line that Alaskan posted. I wish all directions were as easy to follow and so clearly put in writing and pictures. My only question though, is concerning those extra pipes that we won't use, do you cut them off, leave em on, plug them or what?? Thanking you in advance for the answer, Alaskan.
Last edited by craigmar on Sat May 28, 2011 11:58 pm, edited 1 time in total.
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Post by skater »

If it's leaking out the pressure relief valve, why not just replace the valve for ~$20? They do go bad, and any RV parts store should have one.
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water tank

Post by craigmar »

I thought about that option but after pulling all the insulation off looking for another leak as the whole cardboard backing was wet, I figure I might as well replace the tank seeing as it's what about 20 yr's old and I'm going to have to take the unit out to either reinsulate with batting or try to get one of those foam covers if they sell em so what the hey! We have been very fortunate as this van has not had very many problems as compared to some that I've read about and so this repair is kind of a drop in the bucket and will ensure, I hope, be good for another ten or more years at least and if it goes 20 then hopefully it will outlive me.
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short update

Post by craigmar »

after posting to Skater I did a search and did find that Atwood does offer either a cardboard and blanket insulation kit or a foam unit like the one pictured by Alaskan. They are priced about 8 and 15 dollars respectively so I may have to re-think the solution to my problem and maybe use the money saved by going the cheaper alternative, in filling the tanks for another adventure instead.
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Post by Alaskan »

If you've discovered wet cardboard on the rear of the tank it mostly likely has damage either from freezing or from electrolysis...and therefore it needs to come out.

The molded foam covering comes with the kit as does a new relief valve.

The tubes (input & output) that you asked about, its simply a heat exchanger within the tank therefore if you don't use them they require no caps and certainly not removal.

The drain plug should be the type with an anode to help prevent electrolysis...
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Waterheater

Post by craigmar »

Thank you for the reply's. Upon further inspection, it was not the relief valve but a split in the tank around the threaded area of the relief valve so it appeared to be the valve that was leaking. I have googled various sites for a re-line tank and it pays to shop around as there are quite a few price differences. I wonder also what the differences in tanks are as the one Alaskan refers to in his how to article is one number different than what is called for on the model I have. His part is 91642, the one shown for my unit is 91641 and yet all the pictures that I've seen of the tanks, they all look alike. I know that some of the photo's are generic, but is there a difference in all the tanks or do they just change with the year. I know there is a difference between the automatic vs the manually lit ones and also the sizes, 6 vs 10 gallons but all the 6 gallon tanks look to be the same.
Last edited by craigmar on Mon May 30, 2011 5:00 pm, edited 1 time in total.
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Post by Alaskan »

via Google...

Looking at pictures of that other number the heat exchanger, tube welding to the back, is not on that model.

That heat exchanger is used when you would run water lines from your engine cooling system to assist in making warm/hot water...common in boat applications, not so common in RV's and certainly not in a B190 where the engine is on the other end if the vehicle.. :)

Therefore, either number will be fine but I'd go for the part number without the heat exchanger

And yes...I see a huge difference in pricing on the net.
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re-line tank

Post by craigmar »

Your right Alaskan, I called Atwood today and talked to a rep that said the only difference is the heat exchanger tube on the back and either one could be used. He could not give an answer as to the price differences noted with the various sites and why the 42 might be cheaper on some sites and the 41 cheaper on others. It does pay to shop around especially on the shipping.
Atwood has a web site, www.atwoodmobile.com that has some manuals for thier products that you can download and also a link to fantastic fan as apparently they purchased that company in the past
Last edited by craigmar on Wed Jun 22, 2011 7:30 pm, edited 1 time in total.
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water heater

Post by craigmar »

Well,I hope this will be my last post on this subject. As noted in above posts, Alaskan did a great write up, enableing a person to easily repair a damaged water heater and/or water tank. Following his instructions it was no problem geting the unit out, in fact, I think the hardest part of the job is the clean up of the compartment and getting all the old caulking off. In shoping around, various prices could be found from $160 - over $500 for a totally new unit. Because my unit was an original with the 91 van it was going to be cheaper to get just the tank but them my dumb side turned off and I went to the local newpaper and their web site with classified ad's and found (motorhomes and parts) several local sources that were not dealers per say, offering everything from rewelding the tank split to new units taken from crashed motorhomes to refurbished units etc. maybe interest also for Onan gen sets for only a few hundred dollars versus thousands with retailers. I didn't think that a re-weld on my tank was a good idea because it was split right above and on both side of the pressure relief valve so instead I bought a unit taken out of a motor home which was a model G6A-8E which retails on the high end for over $500 and I paid out $150 plus a 1 year warranty ( the person I bought it from told me if I ever had a problem, regardless of time, that he would replace it. Doesn't get better than that.)
I have the new water line parts and am also putting in a ball valve like the one Alaskan installed so hopefully now with everything ready to go, I'm through posting on this subject.
One note, it does pay to shop around.
I thought I was through with this post but just wanted to say that everything went well except that I chose to wrap the tank with insulation only to find that the tank would not fit in the enclosure, found out that the dealer had taken the 6 gallon tank off and installed a 10 gallon so after taking the insulation from the top and sides, I left the bottom blanket on, installed everything with no further problems. I then used a can and 1/2 of expanding foam and covered the rest of the tank with that. It looks kinda like a blob from outer space since I haven't had time to sand it down and paint as the daughters were going to take it out but the insulation works great, hot water for more than two days and warm water after using some for dishes etc. sooner or later I will have to fire it up again but it is saving on propane by keeping everything hot.
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