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Rick, Construction Supervisor
Category: Plumbing
Satisfied Customers: 21780
Experience:  Licensed Master plumber with 40+ yrs. experience.
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I have two electric hot water heaters (50 gallons each) each

Customer Question

I have two electric hot water heaters (50 gallons each) each supplying different sides of my home. I am on municipal water. Do I need one larger expansion tank or do I need two smaller ones for each? I have been told I can put one on the supply line before both water heaters. Also my water pressure is 120 psi at an outside water spigot. There is a 25-75 psi PRV on the supply line. I have adjusted the valve and pressure did not change. Do I need to replace the PRV?
Submitted: 1 year ago.
Category: Plumbing
Expert:  Rick replied 1 year ago.

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

For expansion tanks you can do either. Whichever is more convenient but if you decide to go with 1 tank it must be sized for the combined storage capacity of both tanks. It really doesn't matter where you put the tanks since the pressure will equalize throughout all the piping in the house. Re: the PRV; if the pressure doesn't drop after you adjust the PRV and then draw some water to alleviate the excess pressure then you need a new PRV. You need to measure static pressure (no water running).