Would like to heat a hot tub from storage?

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Got the hot tub hooked two years ago this July. Just teed into one of the jet hoses and into the drain hose. Stainless steel pump draws from the jet hose higher in the tub, through a heat exchanger, and returns heated water to the drain line in the bottom of the tub.

In my case I added a UV sterilizer circuit that runs recirculating flow a few hours a day. Works real well, we dose the system with chlorine when we change the water a couple times a year, but other than that no chemicals and the water stays clear and fresh.

https://www.hearth.com/talk/threads/hot-tub-subsystem.69521/
 
Got the hot tub hooked two years ago this July. Just teed into one of the jet hoses and into the drain hose. Stainless steel pump draws from the jet hose higher in the tub, through a heat exchanger, and returns heated water to the drain line in the bottom of the tub.

In my case I added a UV sterilizer circuit that runs recirculating flow a few hours a day. Works real well, we dose the system with chlorine when we change the water a couple times a year, but other than that no chemicals and the water stays clear and fresh.

https://www.hearth.com/talk/threads/hot-tub-subsystem.69521/


Sounds good. As I get farther into the project, there will be more questions. Thanks!
 
What exactly is a hot tube?

hot-tub-care.jpg
 
Sounds good. As I get father into the project, there will be more questions. Thanks!
Why, does your dad usually ask a lot of questions? (or were you referring to your priest?)
 
I guess the Canadian Huked on Foniks is a bit different than ours?! :p
 
I was just teasing. I wanted to post something so that I was subscribed to the thread in case you get going on this idea.
 
Awesome....
 
I have a hot tub I plan to hook up to the boiler this summer. I'll be watching .
 
I copied nofossils design and plumbed a heat exchanger in line with the electric heater. Everything works like it did except instead of turning on the 220v heater it closes a relay to the zone valve down stairs, and its treated just like any other zone. The only drawback is sometimes it heats too quickly and I get an "overheat" shutdown on the tub. I just press reset and allis fine.
 
How do you keep the lines between the tub and the boiler from freezing when it is not calling for heat or if the boiler is out etc...
 
How do you keep the lines between the tub and the boiler from freezing when it is not calling for heat or if the boiler is out etc...

I insulated the lines between the house and the tub, only about 8 ft worth. While keeping the tube at 104 degrees it cycles fairly often, so it never gets a chance to freeze. The colder it gets the more often it cycles. I have storage so I'm never really out of heat. Even if the storage got really low it would just keep calling for heat and keep circulating the water. I suppose if I lost power for an extended period of time I might have a problem. But then again I've got backups to my backups.
 
I hooked mine up last summer. I did it a little different than ewdudley. I installed a 316 shell-and-tube HX in the hot tub and plumbed it in parallel with my furnace coil. Since my circulator is always on, it is always getting hot water. The HX is in series with the hot tub electric element, so all I would need to do is just install a switch to disable the electric element and the hot tub controls will take care of the rest. I haven't actually gotten around to this yet as the hot tub generally stayed above the set point, just from heating during daily filter cycles. I also have about 8' of lines that are installed within a deck joist cavity. I insulated these with rigid polyeurethane and about a dozen cans of great stuff (not highly recommended).
 
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