Expansion tank location ideas

**bones1** · 01-12-2012, 11:30 AM

I have a 3week old 66 gallon electric tank installed and at the time the guys didn't know there was a check valve in the whole house filter. I now need to install a expansion tank. I put a gauge on the bottom heater drain valve last night and it went to 115 lbs.The water heater has the cold inlet entering on the bottom and the top cold feed capped off of course.Would there be a problem with installing the expansion tank to the top of the heater in the capped off line?.I think it should work but would like opinions on this.
Thanks.

**ballvalve** · 01-12-2012, 12:13 PM

locate it on the store shelf. Heres an option, but noone around here likes it:

http://www.watts.com/pages/_products...ls.asp?pid=564

**Hackney plumbing** · 01-12-2012, 01:00 PM

It would be best to locate the expansion tank so that it doesn't stay hot all the time. Install the expansion tank between the tanks cold water stop valve and the tank. I personally would not screw it directly into the tank. If the expansion tank stays hot all the time the rubber diaphram inside the expansion tank will fail quicker.

If your cold water feed line connects to the bottom of the water heater,you also need an atmospheric vaccum breaker installed above the tank to keep the water heater from siphoning all the water out of the heater if the cold water line is broken and the water turned off.......for example...the main water line to the house breaks and you turn your pump or city water meter off,the water heater will siphon itself.

**bones1** · 01-12-2012, 01:12 PM

Thanks for the replies. I was not going to screw it directly on the tank but mount it on a wall about 3 ft away and above the tank. But an expansion tank fed from the top cold port 'dip tube" would function properly if my heater was fed from the bottom ?.

Quote
"If your cold water feed line connects to the bottom of the water heater,you also need an atmospheric vacuum breaker installed above the tank to keep the water heater from siphoning all the water out of the heater if the cold water line is broken and the water turned off.......for example...the main water line to the house breaks and you turn your pump or city water meter off,the water heater will siphon itself. "
No one ever brought that up when the system was installed, go figure.

**Hackney plumbing** · 01-12-2012, 01:22 PM

Originally Posted by bones1

Thanks for the replies. I was not going to screw it directly on the tank but mount it on a wall about 3 ft away and above the tank. But an expansion tank fed from the top cold port 'dip tube" would function properly if my heater was fed from the bottom ?.

Quote
"If your cold water feed line connects to the bottom of the water heater,you also need an atmospheric vacuum breaker installed above the tank to keep the water heater from siphoning all the water out of the heater if the cold water line is broken and the water turned off.......for example...the main water line to the house breaks and you turn your pump or city water meter off,the water heater will siphon itself. "
No one ever brought that up when the system was installed, go figure.

The diptube is not serving a function any longer if the cold is fed to the bottom. It can be removed. If you chose not to remove it the expansion tank will still work with the diptube left in the heater. I personally would remove the dip tube if its not being used.

You need the vaccum breaker installed. Install it in the cold water feed LINE and make sure the piping extends above the top of the tank by atleast 6" before screwing the vaccum breaker in.

**bones1** · 01-12-2012, 01:55 PM

So an expansion tank fed from the top cold port 'dip tube", that is now capped off , would function properly if my heater was fed from the bottom ?. I just need to know if this is a yes or no before I proceed any further.
Thanks for the info.

**Terry** · 01-12-2012, 01:58 PM

I have my expansion tank ten feet away. Anywhere in the system will work.

**bones1** · 01-12-2012, 02:14 PM

Hi Terry, thanks for the reply. My tank is bottom fed so I will plumb the expansion tank from the top cold capped off fitting and will work fine in your opinion.

**Hackney plumbing** · 01-12-2012, 02:27 PM

Locating the tank as to prevent convection from the water heater is a good practice to follow if possible. As I stated before,the rubber will fail sooner from the heat.

**bones1** · 01-12-2012, 02:42 PM

This was a reply I got on another forum: " You can place an expansion tank anywhere between the check valve and WH". In my case the tank would not be between the check valve and heater if I used the top cold port...true, does this matter?

**jadnashua** · 01-12-2012, 04:16 PM

It will work where you indicate. The critical thing is you want it on the cold water side (heated water would degrade the diaphram quicker), and it needs to be in a place on the tank side of the checkvalve. Basically on either port of the heater designed for cold would work as it is totally open between the two. Not sure why you're using the low feed, but it should work...the upper one with the dip tube does as well, and it's often easier.

**bones1** · 01-12-2012, 04:20 PM

Thanks for the input. I will post a picture of my( plumbers) set up later tonight.

**bones1** · 01-12-2012, 08:11 PM

Some pictures of my heater Name: IMG_0629 (640x480).jpg
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Name: IMG_0628.JPG
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The white GE filter on the right is the one with the built in unadvertised check valve causing the need for the expansion tank. The gauge pegged at 115 lbs on recovery.