Extra-Large Water Heater Expansion Tank
Hello and thank you for your time.
I recently purchased a house in which I’m preparing to do some upgrades, including replacing the water heaters. Right now there are 2 small electric tank heaters (in parallel) that are original to the house–late 70s. I plan to install one HPWH to replace them.
In the crawlspace of the house there is a very large water tank upstream of the water heaters. My guess is about 60-80 gallons, situated horizontally on concrete pedestals. The main cold water line branches to this tank, a line exits the tank and feeds only the cold inlets on both WHs. No ordinary expansion tanks on the WHs.
The only explanation I can think of is an expansion tank, but why so large? Has anyone ever encountered something similar? The reason I ask is because I’d like to remove it if unnecessary (add a regular expansion tank with the WH replacement). The house water is spring fed and gravity pressurized to about 80 psi. No backflow valves or anything like that.
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