Hot tub project

[lawandorder]

So I am in the process of pickig out a hot tub for our deck and have a few questions. I am considering hooking into myTarm system. How is this best comleted. One issue is that my Tarm is in a boiler room behind my garage, piped underground to my house but the hot tub would be installed on the far side of the house. Where do i hook up for the hot tub?? At the point where the piping from the boiler enters the house or where i tie into my home system? How much more wood would I be usng and how do I figure out what size heat exchanger should i look for? I plan on buying a hot tub that is well insulated and would be installed on a raised deck off the front of the house. I plan on also insulating the underneath/sides of the deck to help with wind/snow etc... Sorry for so many questions but I want to plan for it now so I can figure out the best course to follow. Thanks

 

[bruce]

build that deck strong enough to hold a car!! my hut tub with 330 gallons plus the shell and 4 people is over 2 tons in 96 sq ft
that will be much cheaper than my electric bill

 

[Nofossil]

Several people (including me) have done it. I built a DIY exchanger and run it as a zone on my heating system. There are several threads here plus some explanation on my site (in my sig).

 

[lawandorder]

nofo- did u notice a large increase in ur wood consumption?

 

[Bad Wolf]

I used the No fossil design for a heat exchanger run as an extra zone. Its hard to tell what the increase in wood usage was since each year is different just because the temps are different. If I had to venture a guess, I'd say no more than a cord in a year. That is from 7 to 8 cords. I keep the tub at 104f and we had some pretty cold nights here in the last year. I only glitch I've found is that there must be some residual heat in the HX or something because every now and then I get an "OH" reading meaning "over heat" and the tub shuts down. I just hit the temp button and it will display the current temp and come back on if its below the set point. I may install a tempering valve so the HX doesn't see the same 180f degree F water that the house sees. Even when its bitterly cold out the tub only calls for heat for a minute or two at a time.

Greg H

 

[Nofossil]

I never noticed an increase in wood consumption, but that's because I had the hot tub plumbed in to the hydronics before I had a wood boiler so the hot tub has always been part of my heat load. I think it's maybe 30,000 BTU on a coldish day.

 

[bpirger]

Did you place the HX at the tub? Is there room inside the tub for this? Or can you actually get the tub with a HX plumbed already within its plumbing so it is just a matter of hooking up two lines? I could imagine setting a controller to keep the tub at say 104 with the boiler HX and setting the electric control within the tub to maintain say 95, then if the fire ever goes out or for whatever reason the hot water isn't hot...the electric will kick in. Is this readily doable? Are there any tub manufactuers that are more setup for this than the other? I have a spot on the patio for the tub, set it up when I did the pour back in 2003, but never installed a tub. Someday....

 

[Nofossil]

Did you place the HX at the tub? Is there room inside the tub for this? Or can you actually get the tub with a HX plumbed already within its plumbing so it is just a matter of hooking up two lines? I could imagine setting a controller to keep the tub at say 104 with the boiler HX and setting the electric control within the tub to maintain say 95, then if the fire ever goes out or for whatever reason the hot water isn't hot...the electric will kick in. Is this readily doable? Are there any tub manufactuers that are more setup for this than the other? I have a spot on the patio for the tub, set it up when I did the pour back in 2003, but never installed a tub. Someday....

I put the tub against an outside basement wall and cut through the wall so that I get at all the tub mechanicals from the basement. The HX is mounted in the basement next to the tub. I don't think ANY tub manufacturer ships with a HX installed.

I use the tub's built-in controller - I just wired a relay with a 220vac coil in place of the heating element, and the relay contacts act as a thermostat to call for heat for the hot tub zone.

My 'no wood' backup for DHW and space heating is the oil boiler. It's also my backup for the hot tub. I use my controller and a switch on the wall to manage the priority of the hot tub. If I'm not going to use it, it's the lowest priority heat load and it doesn't get heated from storage or oil. If I want to use it I throw the priority switch and my controller finds heat for it wherever it can, including storage or oil.

 

[lawandorder]

One of my concerns is the hookups into aheat exchanger and will here be enough room to handle all the hookups and controls as well as wether or not this is cost effective

 

[wood thing]

This is a project that I would like to do as well. I have an indirect hot water tank not being used. Would this work for a heat exchanger for the hot tub ? It is 40 gal. Thanks

 

[Bad Wolf]

My HX is actually outside the tub enclosure under the steps. My HX is in series with the electric heater, I just installed some 90's at the unions between the pump and the heater and and looped it out and back in again. That way I can always return it to the original set up if I want. I wrapped the HX in insulation and covered it with an extra piece of EPDM. The Pex lines are insulated with the black 3/4 foam from Home Depot. The tub cycles often enough that I never worry about freeze ups. Probably losing more heat than I should but it works. I suppose I could have gotten another temp sensor and relay, and left the existing one set at 95 but I'm basically lazy.

 

[afblue]

I am sure an indirect DHW tank will work, you will have to plumb it so it cuts down the flow into the hot water tank becuase it needs time heat the water. My only other concern is the chemicals in the hot tub if they would eat away indirect hot water tank. The indirect water tank would have to be set to a low temp to not overheat the hot tub water, if it was the case of chlorine, and it vaporize. If you are using a salt water system like a pool, anything steel would also be a caution.

 

[lawandorder]

So, I am still trying to figure all of this out but one concern now is will this obviously void my warranty for the hot tub?? Maybe I should wait until the first year is over and make sure everything is working with the hot tub before its modified