Heater install....bypass line ?

Jun 1, 2012
Installing a heater this weekend. Should I install a bypass line for when the heater is not in use ? Ive heard yes and no but can someone explain the pros and cons.

Thanks ...love the site..learning so much
Jun 1, 2012
Thanks for the response....its possible I may have confused...Im talking on the water side. A bypass line for water to bypass the filter when not in use to continue to run the pump and filter.

I understand that I can just turn off the heater when not in use but continuing to run the water through the heater will limit the life of the heater. ( ?)


LifeTime Supporter
Dec 8, 2010
Mount Airy, Maryland
I don't think it will limit the life of the heater to run water through it all the time. To the contrary, stopping the flow of water through the heater would probably shorten the life of the heater more if you take into account that there is salt in the water and letting the heater dry up would certainly create some corrosion. Having a bypass would be effective if you ever had to do repairs on the heater, but you could certainly create a bypass when and if that happens. I don't have a bypass for my heater and run the heater pretty infrequently.


LifeTime Supporter
Jun 4, 2007
I have a bypass for the heater so if/when I need to replace it no worries. It's very easy to do and you won't have to worry about it later.


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
The advantage to having a bypass is that your system will run more efficiently when the heater is bypassed. The disadvantage is that a bypass means more parts, which means more ways for things to fail and more ways to make mistakes. For example, certain incorrect settings on a bypass can damage the heater (i.e. turning the heater on with one side on and the other off).