Installing Gas heater

[jrv331]

This is a question for those of you with heaters. Is there any harm to constantly running water through the heater when it is off ? Will I extend the heaters life if I bypass it when its off? Will the constant water flow corrode the exchanger sooner?

I know I should have a bypass just incase something goes wrong with the heater, but I can handle that another way.

Thanks
John

 

[JasonLion]

Having a bypass is really nice for a couple of reasons, but most people don't actually have one. Aside from some unusual situations, the heater will last just about as long without a bypass as with. The most common situation where you might have to have a bypass is when the design flow rate of the heater is lower than the flow rate of your system, but that is fairly uncommon.

 

[jrv331]

Jason,
Thanks for the help. My pump is well with in the heaters limits. I was thinking of installing a by pass to avoid the heater when it was off, but then was thinking of what would happen to the water while it sat in the exchanger. Probably come out rusty and do more harm to the exchanger.
Thanks
John

 

[spishex]

I find no noticeable difference in the life of heaters with bypasses vs. without. And as you said, the still water becomes as much an issue as erosion would be. It also becomes an excuse to ignore the heater which can lead to small problems becoming worse.

In fact, I just got in from my last job of the day which involved a bypass doing more harm then good. The customer called Pentair who in turn sent me out for a warranty call because the heater wasn't working. The bypass had been left open and the heater was under pressure but with little actual water flow going through it and was thus overheating.

They can be useful but they won't make or break your heater. Your much more likely to have a problem from bad water chemistry than excessive flow.