Dual State Water Heaters advice

Old 09-14-15, 05:59 PM
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Dual State Water Heaters advice

Hello - I have Dual 40 gal Natural Gas State Water Heaters and one is starting to leak. I was hoping for advice please.

Tank Info.:
- Models #s PR6 40 NBRT971 (leaking)
PR6 40 NORT980

- Input 38,000

- Made 1996

We noticed that the water was not warming up very hot anymore and knew it was time to find some replacements.

The last couple days I have been looking into maybe going tankless and now I have noticed one of the tanks is leaking into the drain pan. There is some rust & corrosion and now feel that I just need to forget the tankless idea and get these replaced fast.

So here is what I need some advice with.

1. The one unit that is for the upstairs has barley ever been used, besides trying to keep some water running through the pipes every once in a while. Since they are both over 15 years, the one unused one that looks brand new, do I need to replace both right now or can I what on the barley used one? It does still work, and not sure how bad the build up might be, but wanted to if I should do both at the same time?

2. Since we have nobody using the upstairs hot water, can we just get 1 - 50 gallon unit to replace both of the 40's and re-plumb to feed hot-water upstairs and down stairs?

3. It looks like both units water supply is dasiey chained together and the only valve I see is one before the upstairs unit. (The one not leaking) I would really like to shut the water off to the one that is leaking, but would shut off water to both? Am I missing something or is this how dual systems are usually plumbed?

4. I just replace my ACs logic board and blower motors, so I not afraid to jump in and try replacing these on my own, but want to know if there are hidden problems that can arise? What I mean is it looks like the water supply on top, gas hook-up on the side and flute on top. A couple restraining straps, over flow pipe and that looks like that is it. If everything gets tighten down and I get the old heavy ones drained and out of the way, could it be as easy/hard as lugging the new ones in place and making the right hook-ups?

I am unaware if codes have changes since these were installed, but trying to get some insight before I start to tackle this project.

Sorry so long, thanks in advance,
Old 09-20-15, 06:08 PM
Join Date: Mar 2010
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In many cities you need a permit to install a water heater. In many cities the qualifications needed to hook up gas are more strict than for hooking up water or electricity.

In most cases it is necessary to shut off water to both water heaters regardless of how they are plumbed.

At the very least you need to:

1. Very important, shut off heat for both heaters.
2. Turn off water.
3. Drain the leaking heater.
4. Disconnect the leaking heater.
5. Cap ot join the free inlet and outlet pipes (join for a daisy chain, cap for heaters in parellel)
6. Turn on water supply and also hot tap upstairs.
7. Wait for water to gush from open tap and let it run ffor a minute.
8. Turn good water heater heat back on.

If you replace two water heaters at the same time and they are connected in parallel, shut off one's water supply while waiting for the open hot tap to gush water. After the tap runs water for a minute shut off that heater's supply and open the other heater's water supply and wait for air to clear out and water to resume gushing from the tap for a minute. Finally you can turn the water heaters' heat on.

Last edited by AllanJ; 09-20-15 at 06:43 PM.

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