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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 21997
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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My contractor installed a Weil-McLain water boiler. He said

Customer Question

My contractor installed a Weil-McLain water boiler. He said an expansion tank is not needed. Is one required? What could happen if I don't install one?
JA: How long has this been going on? And how severe is the problem?
Customer: Just a few days. Haven't had to turn the heat on yet
JA: Do you plan on doing the work yourself?
Customer: No, I would hire another contractor
JA: Anything else we should know to help you best?
Customer: No, thank you
Submitted: 4 days ago.
Category: HVAC
Expert:  BillyHvac replied 4 days ago.


My name is ***** ***** I will do my best to assist you. I am looking over your question now and will respond shortly.

Expert:  BillyHvac replied 4 days ago.

Every boiler should have an expansion tank except for steam.

You are heating water..the water expands....that is the entire reason for the tank.

The only way I would say no is if the boiler has a built in expansion tank which I have only seen on a very few imports.

Short story is you have to have an expansion tank to accommodate the water expansion