Electric Water Heater Expansion Tank - Bondiing?

[chuck b]

Installing a new electric water heater in cottage. Have noted in plumbing how-to books, that an expansion tank was situated on the cold water line before entering the water heater cold water inlet.

Is this a new requirement, and what is the benefit. Water heater will be on a well, not city water supply. It will have its own expansion tank.

Also on gas fired water heaters, should you bond the hot and cold water pipes to the natureal gas pipe as well.

Thanks.

[Cookie]

Since your well has a bladder tank you shouldn't need an expansion tank, as long as the water heater is on the same line as the well.

In answer to your second part, you should not bond the hot and cold water pipes to the natural gas pipe.

[LLigetfa]

If you have metal piping, it should be bonded to the electrical service ground. Unless there is a dielectric union insulating the hot side, it should already be bonded through the water heater. The gas piping should already be bonded at the service entrance. No need for additional bonding at the tank.

[hj]

I have a theory, that the hot and cold SHOULD be bonded together at the water heater, especially when di-electric unions are used.

[jadnashua]

As noted, the well's bladder tank should be able to handle any expansion as long as you don't have any extra check valves, you should not need it. But, some locales may require one. You need someplace for water to go when you have a closed system, and a check valve creates that. As long as the bladder tank is on the same side of the check valve as the WH, in theory, no extra one needed.