Another cold weather heater question

[dcpickle]

I under stand I cannot run the heater to help with freezing issues, or to maintain the pool below 68. But we have a spa which can be isolated and heated separately from the pool. I expected to be able to put it in spa mode and heat the spa to some really warm temp and maintain it there for some hours, then return to normal pool mode with the heater off. With this scenario, the heater would light up with cold water at first, then stay lit until the water is say 90 degrees, which won't take long. Then maintain at 90 for awhile, then shut off. Do you think this is safe, or a problem? BTW it's a Jandy 400k BTU gas heater.

 

[gkw4815]

I've used my Jandy JXI400 as you've described (ie to heat the spa from low water temperatures) without issue so far (heater is 2 years old).

You don't want to run the heater below 68 degrees or so for extended periods, but unless your spa is very large, you'd probably heat it past 68 degrees within the first 30 minutes or so of running the heater.

 

[JJ_Tex]

That is how I too use my heater. My understanding is that the condensation risk is mitigated when you run your heater continuously to prevent it from cycling on/off.

So heating your spa from 50 to 90 degrees would be fine because your heater would continuously run until reaching the desired temp. Using your heater to keep your pool at 65 degrees would not be okay because the heater would continuously cycle on and off and cause condensation.

Here is more on the topic:

Heater Condensation - Further Reading

www.troublefreepool.com

 

[1poolman1]

I under stand I cannot run the heater to help with freezing issues, or to maintain the pool below 68. But we have a spa which can be isolated and heated separately from the pool. I expected to be able to put it in spa mode and heat the spa to some really warm temp and maintain it there for some hours, then return to normal pool mode with the heater off. With this scenario, the heater would light up with cold water at first, then stay lit until the water is say 90 degrees, which won't take long. Then maintain at 90 for awhile, then shut off. Do you think this is safe, or a problem? BTW it's a Jandy 400k BTU gas heater.

Not a problem. The spa will heat much faster than the issues can occur. By the way, unless you like lukewarm bath water, 90 is somewhat cold for a spa.