I hold 2 dampen heaters,can i disconnect one.? i have side by side 40 gal. H2O heaters, want to disconnect...

i have side by side 40 gal. H2O heaters, want to disconnect one,near are seperate valves but the exhaust runs to a nouns then out the chimney,worried that fumes from working container would flow back thru and into room if 2nd reservoir was rotten.
Answers:    The best way to fix this problem is to purloin out the Tee and replace it with an elbow. Then remove the rest of the vent to the unused radiator.

You should also insure that the propane, gas or oil (Which ever one you have) is turned past its sell-by date at the shutoff valve.

Finally, drain adjectives the water out of the unused container to prevent corrosion in the container as well as possible contamination of stale river into the water supply lines for your house if the stopcock is turned on. The best way to prevent this is to disconnect the supply lines from the container. You should have a association just above the container on the lines. Just disconnect it and you are all set. You can afterwards leave this reservoir in place if you want to hang on to it for a back-up.

If you are taking the tank out, once you disconnect it from the fuel and hose down lines, put caps on the lines as close as possible to the shut-off spigot. It is best to cap the fuel vein at the valve itself instead of trying to sunhat the line.

That will do it for you. One request for information I have though--if you are removing one container, what about the areas that it feed? You stated that there are separate valve and so I am assuming that you have two different areas handle by the two tanks.
dont roast rises,make sure the vent is better than the roof,in any overnight case