Water Heater with built in thermal expansion

[dbailey75]

I just received a letter from the county water system, they're going to install a new water meter and backflow preventer. They've instructed me to have a thermal expansion device installed, but if I have a water heater made in 2001 or later, it should have one built in to the unit. My questions is do water heaters have a thermal expansion tank built in? At this point, my water heater is 11 years old and it's not working a well as it did a few years back so this is a good time to replace it, but do I also need to install a thermal expansion tank?

Thanks
Dan

 

[hj]

espansion

NO HEATERS have an internal expansion device, regardless of when they were manufactured. You have to install an external expansion tank somewhere in the system, or provide for the expansion someway. There are special toilet fill valves which will bleed off excessive pressure so that a tank is not necessary.

 

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[Toolaholic]

yo db

sounds like the city just hired a new engineer

 

[dbailey75]

Thanks for the quick response.

 

[Gary Swart]

Thermal expansion tanks have been extensively discussed on this forum fairly recently. If you can sweat a joint, you can easily install one. Watts has a couple of sizes available and they come with easy to follow instructions. The main things are to support it well and balance the pressure of the tank with the supply. I suggest adding a pressure gauge on the supply side to make this easier. The tanks run about $50, a gauge is $10, and fittings maybe $2. The units are installer between the pressure regulator and the water heater and are usually suspended from the ceiling, but other possible mounting methods are shown in the installation instructions.