Best way to install expansion tank


Old 02-26-20, 01:16 AM
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Best way to install expansion tank

What is the best way to install an expansion tank without sweating pipes? I plan to install a new gas tank soon and the current setup would allow flex lines to connect from the supply lines to the tank. Two ways I have seen or have thought of seem the simplest:

1. put a tee on the cold inlet and hook the supply like to the top. Run a short threaded length of pipe off the side with a 90 and screw the tank into that.

2. put a tee as mentioned above but mount the tank to a bracket on the wall or on a shelf and run a flex line from the tank to the tee.

Are both of these good options and if so, which one is the better set up? Is brass the best type of pipe for this setup, or galvanized?
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Old 02-26-20, 05:31 AM
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What gas tank are you referring to? Any gas supply to your heater will be using totally separate piping than an expansion tank which will get plumbed into the water line.

Which way to mount the expansion tank depends a lot on where your heater is located and the space available. I do not like a tank hanging sideways only supported by the pipe. I would mount the tank straight out the top and have your water line come in on the side of the T. Or you can remotely mount the tank like you mentioned. Just make sure to properly support everything.

Personally I would sweat fittings over using threaded as it can sometimes be difficult to get them tight enough to seal AND get a T to line up the way you need.
Old 02-26-20, 05:51 AM
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Gas tank as in gas fired storage tank water heater. All kinds of storage tank water heaters need expansion tanks.

A belt or strap attached to the ceiling joists can also be used to support an expansion tank. Use a stud finder to find a joist if the basement is finished. But do not jerk the expansion tank upward.

Under some conditions an expansion tank can fill with water. Water is heavy and an otherwise unsuppoorted waterlogged tank can put a lot of strain on the plumbing, possibly resulting in a major leak.
Old 02-26-20, 10:52 AM
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I can't put the tank straight up from the water inlet on the tank because the inlet is right next to the exhaust pipe so there wouldn't be room for the tank. I have seen a lot of examples like the one below where it is off to the side so it can clean the exhaust pipe, but I do understand the tank would get heavy if it filled. What if I put a block or something between the top of the tank and the horizontal pipe to support the weight of the tank?

The other option I thought of was just mounting the tank on the wall like the lower picture (probably with the water outlet on the bottom though instead of the top) and running a flex line to the tee.

Will either of those methods work?

This last pic shows my current setup and a new tank is going to be similar where the vent would be in the way.

Old 02-29-20, 01:04 PM
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After going to a couple of different stores and asking for their opinions, they all suggested the first method I listed above: tee, nipple, 90, threading the tank into it. The last guy thought I only needed a 2 gallon since that is all that is required for a 50 gallon water heater but said it will be fine if I put a block of wood or something under the pipe to support it. I bought all of the brass fittings so I think I will go this route. Should I still stick with the 5 gallon though or get a 2?
Old 03-01-20, 05:20 PM
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I'd use the smaller one. .................
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