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Tcp
Orientation of expansion tank for water heater.
Tcp

Looking to install an expansion tank for my new water heater. The old one didnt have one when I bought the house and just crapped out yesterday. Now I know the tank needs to be supported because if it ever fills with water it will be very heavy. I read that it shouldnt be installed upside down because if it should fill with water it will be a mess when removing it. However, can one be installed right above the cold water inlet to the boiler using a tee? if it should fill up once you drain down the boiler it will drain into the boiler no? Also the weight would be transferred straight down so no need to hang?

dj1
Re: Orientation of expansion tank for water heater.
dj1

First determine whether or not an expansion tank will be beneficial for you. If you have a check valve or pressure reducing valve in your system, then an expansion tank could be a good addition. You have to choose the right size tank to match your WH size in gallons and your water pressure.

Now, there are a few good locations for the tank, and they are all around the cold supply side to the water heater.

Your suggestion to mount the tank exactly on the water heater could work in certain situations, but I prefer the tank to be mounted about a foot away from the water heater - but still on a T in the cold supply pipe to the WH. Then support the tank with a custom built shelf off the wall.

Up, down or side way mount - doesn't matter. The main thing is to have the tank rest on the shelf.

Another good idea for convenience is to install a shut off ball valve, after the T and on the way to the tank.

Tcp
Re: Orientation of expansion tank for water heater.
Tcp

Yes I believe I do have a prv in the street. How would I go about sizing the tank? I have a 2.1 Watts from HD sitting in my garage. I have a 50gal kenmore gas heater. I'm not too sure of the pressure coming into the home at the moment. Will pick up a hose thread gauge from HD later today.

dj1
Re: Orientation of expansion tank for water heater.
dj1

Google "sizing an expansion tank" and you'll get sites with sizing calculators.

They will ask you to fill in info like: WH size in gallons (50), water pressure in the house (should be between 50 and 75), WH water temp (I keep mine below 120 in winter and below 105 in the summer), and so on. Then you'll get the recommended expansion tank size in gallons.

A 2.1 gal may or may not fit your needs, I'm not sure. If not, I'm sure HD will take it back.

Send pictures, you can upload them on a host like photobucket.com then post the link here.

Tcp
Re: Orientation of expansion tank for water heater.
Tcp

There was a chart right on the box doh! My 50 gallon heater and pressure does fall within that tank but how come some other brand tank require larger tanks for the same specs? Couldn't position it vertically so had to go the horizontal option also I like your idea of the ball valve before the expansion tank. Although the internet says not to do that because then you can isolate the tank from the hw heater, who is going to turn that valve?!?! not me! And you are right it is so much easier to change it out in the future. Here are some photos of the finished job (will insualte soon... lol). Thanks for your input! Let me know if you see something I did wrong.

Tcp
Re: Orientation of expansion tank for water heater.
Tcp

Hey I was also wondering, before I installed the flue vent there was a metal piece suspended or hanging over the opening of the vent. What is that?

dj1
Re: Orientation of expansion tank for water heater.
dj1

The installation looks good. If wall straps are required in your city, just add them now (they are required in earthquake zones, to make sure the WH doesn't topple down).

The spiral metal strip hanging down from the vent opening is call the flue baffle. It helps in the process of discharging gases produced by the pilot light and burner through the vent. It also helps in heat distribution and exchange inside the WH tank.

Mastercarpentry
Re: Orientation of expansion tank for water heater.
Mastercarpentry

The flue baffle adds greatly to efficiency, up to 40% better. Whatever supports the tank has to be able to hold it if it fills with water should the diaphragm fail. Being mainly a Carpenter with limited soldering skill I think plumbing differently. Valves and unions go in wherever a part will eventually need replacing with a copper or galvanized system. Plastic piping is easy to patch and recouple so that doesn't need the extras. Make future work easy when you can ;)

Phil

Tcp
Re: Orientation of expansion tank for water heater.
Tcp

Tested my house pressure the other day and got 80psi! Called the water company and they are sending someone down to check. I had left the tank set at factory pressure (40psi). If I wait for them to turn down the pressure before setting the air pressure in the tank will that harm it in the meantime? Also I'm thinking about installing a pressure gauge on the cold water line by the tank. Is that something good to have? I will be able to see spikes down the road if the tank fails. Couldnt find much of anything about it on the web which leads me to believe its not common practice?

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