My hot water heater seems to occasionally cause the water pressure to increase a lot. Is this what the expansion tank is for? If so how large is the tank and where does it go?

my hot water heater seems to occasionally cause the water pressure to increase a lot. Is this what the expansion tank is for? If so how large is the tank and where does it go?

Hey Jim,
When water heats it expands. If you have a check valve or a backflow preventer installed on the cold water supply to your house this leaves the hot water no where to expand to except out the T&P relief valve on the heater. The expansion tank gives the hotwater a place ro expand. Check out expansion tanks at; http://www.accentshopping.com/store/heating/waterheaters/expansiontanksdomesticpotablewater/DET-5-M1.asp
And a typical installation,(see image). Good luck and ifyou have more questions I'm as close as a click. Tom