Bypass Valve On Heater

[jrv331]

When installing a pool heater is it necessary (or a good idea) to install a bypass valve so the water doesn't flow through the heater when its off? I have been reading on the internet and some sites say its needed and some say it is not.

I got a used Pentair Minimax CH and the manual says its needed if water pressure is above 120gpm.

Thanks for any advice
John

[CarlD]

I would assume that each manufacturer has its own requirements and you want to follow them to avoid voiding their warranty.

[aylad]

Equipment issues are NOT my forte, but I would think that installing the bypass valve is a good idea if for no other reason than to redirect water in the event of a problem with the heater. Heater coils have been known to degrade over time and create metal staining, etc, and it would seem to me to be a good idea to have an alternative in the event of problems, as long as it doesn't void the warranty.

Janet

[jrv331]

The heater is used so there's no warranty. The manual only mentions a bypass valve if water pressure is over 120gph, my pumps limit is only 80 on high. I was thinking of just installing the bypass incase something happens to the heater(like mentioned above) and to bypass the heater when its off.

I have read several threads of chemicals wearing out the heat exchanger, so bypassing it might extend its use time.
Thanks
john

[thepoolman1]

If you are going to do this, make sure to drain the heat exchanger when the water is not in circulation through the heater. You will have deposits left on the inside of the tubes when the water evaporates if you do not. They will build up, at times to the point of blocking the tubes nearly closed. If your system is not capable of of moving the maximum water flow, I would only put the bypass in case of there a problem with the heat exchanger. This is very rare if you maintain good water balance. Also, it is good to fire a heater at least once a month (once a week is better) for about 5 minutes to make sure it works and to help keep out the "critters."

The reality is that this is a lot of extra work and expense for very little return, unless it gives you peace of mind. If you are going to do this, make sure that you use valves made of CPVC (like Pentair, Hayward, or Jandy) so that there is less likely to be heat damage to the body.

[Poconos]

When I had my heater I did do the plumbing to be able to bypass the heater only to cut the flow resistance when the heater wasn't being used. As for using CPVC, I don't think that is necessary. In any heater operation situation I can't see any way the water temperature in the pipes can be anywhere near the softening point of plain PVC. I admit I can't remember what the recommended temperature limit for PVC is but it is way above what any water in the system should be. Please correct me if I'm wrong or missing something.
Al

[jrv331]

Thanks for all the help. I'm using Pentair 3 way valves for the bypass. I Mostly want to be able to avoid running water through the heater when shocking with high levels of bleach or some other chemical.
Thanks
John