Remodeling Tips and Reviews

Tips on Installing a Tankless Gas Hot Water Heater

Tips on Installing a Tankless Gas Hot Water Heater

Jan 10, 2012

While installing  a Takagi Unit in an attic recently there was a debate about code issues concerning the installation of these units. The question specifically detailed the water line plumbing to and from the unit itself. I assumed the code requirements were the same as a standard Hot Water heater. Turned out I was right. There are newer isolation valves on the market that can turn off and drain out the unit from both the cold feed and the hot feed. These are great for maintenance but are not mandatory in the 2006 Residential Code Book. It simply states that :

A 3/4″ water line must feed the unit with a ball valve to cut off the supply. It also states the a T/P overflow valve must be connected on the hot supply side of the unit as close to the unit as possible. The T/P must also connect into a 3/4″ line that runs to the outside of the house in the event the valve is opened.

A few other tips are that the gas line needs to be 3/4″ and have a ball valve. You can use a flexible gas hose to tie the line into the unit.

If the unit requires electric then you must be able to unplug or switch the unit off. I prefer a switch since it is simpler to turn off and on as needed. Make sure and label it so people don’t just flip it off.

Keep in mind that the venting must be stainless steel and will require a condensation drain for the water that accumulates inside the steel pipe when it is cooling after use.