thermal expansion/ closed water system

[Jerome W. Young]

A.O. smith recommends xpansion tanks on a closed water systems. i had a condo this am and the plumber installed a new heater yesterday. no xpansion tank or device was installed that i could see. Is a condo a "closed water system" and or do they had relief at a common area anywhere?

[Mike Schulz]

Jerome your question is a little hard to decipher and your spelling is horrific :)

I'm going to give it a shot::p
A municipal water system is a (closed water system) and it is under
pressure. That is how the water is delivered to you home. Since the
pressure is greater than atmospheric, when you open the faucet, the
water flows.
But one can argue the wording because for water to flow it has to draw air from somewhere which typically is the vent on top of a water tower.:eek:

In our area you have to take out a permit for water heaters and install it to todays code which includes expansion tanks. I'm not sure about electric water heaters though?

Not sure what you mean by this (and or do they had relief at a common area anywhere?):confused:

[Jerome W. Young]

I was abbreviating, although not that brief for expansion. I know that is not how you spell it. Other than that, I dont see any spelling errors. Thanks for the input.

[Jerome W. Young]

yeah the grammar was bad too. I was in a hurry damn it. :D

[Mike Schulz]

(and or do they had relief at a common area anywhere?):confused:

[Jerry Peck]

A condo building will typically have a closed water system, which requires a 'pressure relief device', which could be just a 'pressure relief valve', which, of course, brings up the question as to 'where in tarnation are you going to dump the pressure relief discharge to? Unless there is a pan under the water heater, and the water heater will not be setting in water, and ... and ...

[Jerome W. Young]

Thanks, What would be an example or alternative to a closed water system?

[Jim Luttrall]

A standard single family home with NO check valve or pressure reducing valve at the meter would be an example of an open system. The water pressure can bleed back into the city water main (ever see the small movement triangle "rock" back and forth when all the water is off in the house?) Any check valve or regulator that impedes the flow of water back to the main makes it a closed system since water can only flow into the system.