Should I install a thermal expansion tank when I install new Gas hot water heater?
My current tank(installed 14 yrs ago when house was built!) does not have one, and I do not have a closed water system ( no check valve to city main) So I do not think it will cause damage without one. I would just ask the city building dept. but then they get curious and charge me $75 to get a permit for the tank install.
Thanks for any info on why we need exp. Tanks and if they are becoming mandatory to install.

Hey Dayslug24...

Codes differ from state to state and even town to town... so no easy way to answer your question here. Even if you knew the particular code in place in your state we would not be able to tell you what your town inspector requires.

If you don't have an expansion tank in place now then it is highly likely that you will not be required to install one now. You could always call the inspector and tell him that your water heater is getting old and you and a friend were wondering/arguing if a new water heater install needs an expansion tank..

I also like the idea of all water heaters getting a permit and getting inspected. $75.00 or less guarantees that your homeowner's insurance will pay for the damages should any occur due to poor manufacturing/materials, and it guarantees that all safety devices have been installed properly. I know this will be hard to believe, and I don't want to get all dramatic over this, but more then a few people have died because water heaters have been installed improperly (temperature and pressure relief valve got installed wrong).

Check out www.waterheaterblast.com (http://www.waterheaterblast.com) to see a video (at bottom of screen) of what can happen when safety devices are installed wrong.

Anyway, hope that helped some. Let me know if have more questions... ok?

MARK

Mark gave you very good advice. From my experience, Thermal Expension is a rare problem - but does happen. I would proceed with installing the heater and if you start experiencing Thermal Expansion problem than I would deal with it. It is relatively easy to install the thermal expansion tank.