Installed heater bypass on new HP, but was it really necessary?

suzook

Well-known member
Apr 15, 2014
570
Senoia, GA
So because of this forum, I DID install a heater bypass on my HP. Very basic, 3 manual ball valves. I am wondering though, when heater is not being used for months in the summer, I have heard bypass it. Well isn't water just sitting in it worse, than water flowing through it? I guess i could disconnect the HP plumbing and let it drain, but that's just a PITA. Just looking for some thoughts.
 
So because of this forum, I DID install a heater bypass on my HP. Very basic, 3 manual ball valves. I am wondering though, when heater is not being used for months in the summer, I have heard bypass it. Well isn't water just sitting in it worse, than water flowing through it? I guess i could disconnect the HP plumbing and let it drain, but that's just a PITA. Just looking for some thoughts.
Looks for a drain plug on the HP. Equipment like that should be drained in freezing weather so I’d guess there’s some kind of winterization port on it.
 
I have a pentair mastertemp and used pentair's instructions for the bypass which calls for a 3 way jandy and a check valve. They suggest leaving the three way partially open to prevent stagnant water sitting in the heater while only having a minuscule impact on flow. The ways yours is installed is great for the event where you need to bypass and remove the heater for maintenance.
 
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I have a pentair mastertemp and used pentair's instructions for the bypass which calls for a 3 way jandy and a check valve. They suggest leaving the three way partially open to prevent stagnant water sitting in the heater while only having a minuscule impact on flow. The ways yours is installed is great for the event where you need to bypass and remove the heater for maintenance.
I will probably just leave it open all the time. I really don't see the issue with water running through it. But, yes, having it, is nice in case i need to remove it from system, or a slam is needed. Although from what i have read, high chlorine shouldn't affect titanium heat exchangers.
 
Although from what i have read, high chlorine shouldn't affect titanium heat exchangers.
Our slam is less harsh than tap water. Possibly 3 to 4x less harsh. So maybe don't ever hose it off and you'll be OK. 😁

I will probably just leave it open all the time. I really don't see the issue with water running through it
That's why we have science. Run it both ways and note the wattage and RPM where all of your functions start to work, such as the SWG or skimming. Maybe it matters on your setup, maybe it doesn't. Report back with your data.
 
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Open all the valves. The water will preferentially flow though the bypass, yet leaving the HP open to flow a little water.

If you need to service the HP, then you can shut the valves to properly bypass it.
 
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Our slam is less harsh than tap water. Possibly 3 to 4x less harsh. So maybe don't ever hose it off and you'll be OK. 😁


That's why we have science. Run it both ways and note the wattage and RPM where all of your functions start to work, such as the SWG or skimming. Maybe it matters on your setup, maybe it doesn't. Report back with your data.
You mean with it open, and then closed to see what rpm SWG needs?
 
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And skimming, cleaning, etc etc. You'll sleep better knowing it matters and it's adjusted to be optimal or that it doesn't matter.
 
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I like purple :)

I need to do this for the summer months - although the geek in me wants to link it to a temp probe and automatically open it when the incoming flow is already above the set point...
 
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If you undo the unions, the heater will drain.

Just support the pipe before loosening the union nuts.

Once it drains, leave the unions connected but loose with a tiny opening between the parts.
 
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Very basic, 3 manual ball valves.
Ball valves are far from ideal. A better option is a quality 3-way diverter and a check valve. But what's done is done. If you do some plumbing renovations in the future, I would recommend switching to that configuration.

Well isn't water just sitting in it worse, than water flowing through it?
When you aren't using the HP, open all the valves. The vast majority of the water will flow through the bypass, a little bit will flow through the HP.
 

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