Installing a bypass valve for my heater

JamesR

Gold Supporter
May 18, 2015
172
Nazareth/PA
I will be installing a new heater this spring. I'd like to have a bypass setup for times when the chemistry may be out of whack or in the very beginning of the season. Could I get away with a single Jandy 3-way installed on the inlet to the heater and have it divert to the outlet plumbing or should I go with three 2-port valves in the typical H pattern to enable me to completely close off the heater and bypass it?
 

Turbo1Ton

Gold Supporter
Dec 26, 2019
534
NE Oklahoma
Pool Size
14500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Check this out.


I would only do a 3 way with a check on the heater outlet, as this can prevent a dead head situation, that is very easy to do with multiple 2 way valves.

--Jeff
 

JamesR

Gold Supporter
May 18, 2015
172
Nazareth/PA
Thanks Tom. I read through that link. Those reasons are exactly why I want it with a bypass this time around. I’ll have to price out a 3 way and check valve vs three 2 port valves. If the heater actually had to be removed from the loop for some unplanned maintenance, would that check valve prevent 100% of the water getting past it. I can see a ball valve being pretty good in a 3 valve setup.
 

JamesW

TFP Expert
Mar 2, 2011
24,208
With 3 valves or (2) 3-way valves, you can end up locking pressure in the heater and that can make it run with no flow.

You would need to make sure that you turned the heater off to prevent it from running with no flow.

You should install a flow switch for the heater connected in series with the pressure switch to prevent running with no flow.
 

Zaffor

Well-known member
Sep 27, 2019
147
Miami
Pool Size
15000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
I use a single 3 way jandy with a check valve before it joins back into the original return plumbing. If operating manually this is simple and easy to operate. I think any time you setup multiple valves, it increases the chance of dead heading the pump.
 

avspin

Gold Supporter
Jun 3, 2015
168
Reno, NV
I opted for two 3 ways because my equipment is 4' below pool level and didn't trust a check valve. I know I have extra work to make sure I don't lock out the heater. But I've trained my self to open each valve halfway, going back and forth. Just makes me more aware. So far all is good.