I was given a hot tub/spa I'd like to hook up to wood boiler?

[VtRv]

Hi all, I found a prize on Craigslist this weekend. A free Hot Springs Jetsetter spa that I'd like to hook up to my Tarm boiler.

I've seen and read a few post on the topic but I'm still not sure what I'm getting into. It looks like I would need another zone and circulator and a heat exchanger to heat the water. I believe it was Nofossil that built a heat exchanger out of PVC and copper. I'd love to get some more info on how this is done.

Is it possible to wire it so that you could still use the built in heater when going away for a period of time so I wouldn't be using my gas boiler to heat the tub, unless this is an efficient way of keeping it. It also has the option of 110 or 220 volts, but set up for 110. Is there any benifit of switching over to 220?

I plan to put the tub on my back deck, or actually sinking it into the deck. How do you insulate the pipes once they leave the house to the tub which will only have a few feet exposed outside?

I hope I'm not getting into an expensive and difficult project but the tub looks in good shape. It's 9 years old but was used in a three season room until the owners decided to give it away due to lack of use.

Any advise, instructions would be appreciated. (layman terms please)

Thanks

 

[ManiacPD]

My friend just hooked his up to his Tarm. I'm headed over there this coming weekend for a cook out. I'll check it out and report back on Monday.

 

[VtRv]

My friend just hooked his up to his Tarm. I'm headed over there this coming weekend for a cook out. I'll check it out and report back on Monday.

That would be excellent thank you.

 

[Gooserider]

Hi all, I found a prize on Craigslist this weekend. A free Hot Springs Jetsetter spa that I'd like to hook up to my Tarm boiler.

I've seen and read a few post on the topic but I'm still not sure what I'm getting into. It looks like I would need another zone and circulator and a heat exchanger to heat the water. I believe it was Nofossil that built a heat exchanger out of PVC and copper. I'd love to get some more info on how this is done.

From what I've gathered, you want your heat exchanger to be made from Stainless Steel, or at least the spa side. Pool and hot-tub chemistry doesn't like copper, and since it's an open system iron and steel are also not good.

Is it possible to wire it so that you could still use the built in heater when going away for a period of time so I wouldn't be using my gas boiler to heat the tub, unless this is an efficient way of keeping it. It also has the option of 110 or 220 volts, but set up for 110. Is there any benifit of switching over to 220?

220 in theory draws less current than 110 power, and puts a more balanced load on your electric distribution panel. The actual power used stays the same. My feeling is that if you have to run a circuit to power the tub (which is likely), it would be better if it were a 220v line, but if you are going to run off an existing 110 line, it shouldn't be a problem to stay on 110.

NOTE! Check your code requirements - hot tubs and pools have a lot of extra and special requirements for electrical circuits feeding them and near by, water and electric can be a deadly combination, so make sure you do it right

It should be possible to set up the electric heaters as a backup, but I'm not sure just what would be involved. My first guess would be to either have some sort of manual control for the switchover, or set up the electrics to maintain a lower than normal temp, and rig the zone controls so that they will only turn on if the wood boiler is operating. That way if the gas boiler is operating the tub zone wouldn't come on, and the electrics would come on at some point when the water cooled down.

I plan to put the tub on my back deck, or actually sinking it into the deck. How do you insulate the pipes once they leave the house to the tub which will only have a few feet exposed outside?

Insulating the pipes should be pretty easy, I'd probably go with one of the wrap-on type insulation options since it sounds like you are going a short distance and will be staying above ground in a pretty sheltered environment. It MIGHT be worth looking at putting an electric heat tape under the insulation as well depending on how your circulation system works.

I hope I'm not getting into an expensive and difficult project but the tub looks in good shape. It's 9 years old but was used in a three season room until the owners decided to give it away due to lack of use.
Any advise, instructions would be appreciated. (layman terms please)

Thanks

I'd guess a middling level project for both cost and difficulty, but probably worth it.

Note that I'm not a pro at this, and haven't actually done this sort of thing, but I've read alot, and am going from that...

Gooserider

 

[btwncentres]

aaagh...just got wireless high speeeed...discovered this sight last night...stayed up 'til me head hurt...amazing site....building a boiler .....in my head......pipes running to where things will be......but as regards hot tubs...I wouldn't live without one... though I just did for 5 days ....which is another ...horror... story.......if you don't like, or have, all that electricity you could put an oil fired water heater ...which can be really cheap to run ... fast tub heat....diesel fuel works great.....then there's waste oil.....in line with the boiler......drill outlet in hot tub.....hook up Grundthingamebob pump....to heat exchanger//boiler...to water heater....to tee connection on main ..BIG...pump intake pipe....put a check valve behind this....the hot water has to go through pump and tub plumbing system...freeze protection....cheap to run....just use the big pump for the jets and to filter now and then....I built tub into a crawl under deck...tub was spray foamed and I insulated to R60 or more....I packed the beggar.....insul foam top...still not done properly...since the boiler doesn't exist I ran with oil all winter... used zip....enough in the tank to reach the outlet and then just dump in a jerry can now and then.........a good boiler would be great and me brother-in-law is importing vacuum tube solar...imagine a little yard of those...moola moola...oh well.... the main point of it all is to get the hot tub going..somehow....wonderful tool.......out all winterday...amazing....before you hardly move in the morning......after work...before bed........goodnight...........boy have I got questions...there are some smart people here.....................

 

[btwncentres]

....eeek..oh yeah..to run on 220 is cheaper... for the wire..same useage...... if going a distance with heavy load...lighter gauge than 110....get rid of heater and you don't need big wire at all....'member to use GFI"s somewhere in there......
Have fun.............

 

[2.beans]

heres some pics on how i tied into the hot tub

 

[Nofossil]

I made my hx out of PVC with 16' of 1/2" copper inside (8 pieces 2' long). Hot tub water is in the PVC pipe, and boiler water is in the copper. My hot tub has a tiny circ that runs 24/7. I just plumbed my hx in place of the factory electric heater and put a relay with a 220vac coil in place of the factory heating element. The relay contacts open a zone valve to allow water to circulate through the HX.

There's a lot more fancy control logic that determines when heat actually gets sent to the hot tub, but that's not necessary for happiness.

Keeping the electric element as backup is a little more complicated. It's a fair amount of current at 220 volts, so you need to be careful about how you mess with it. Basically, you'll probably want a manual 'disable' switch that prevents power from reaching the element.

Here's a link to a picture.

 

[VtRv]

Thank you all for the info. I've spent the day getting the tub up and running (I think). We'll see if it heats up overnight. I want to make sure everything is working before I spend the time and money to retrofit it.

I was able to fix the leak in the heater, which the spa dealer told me needed to be replaced. Mine also has a smaller circulater pump that runs 24/7. The previous owners didn't think it worked but I found a reset and was able to get it to fire up. Now the question is whether it heats up tonight.

Thanks again for all the info..

 

[paul2e]

There is typically a h2o line pressure sensor that will turn off the heater if the circ pump is off.

 

[ManiacPD]

Went to my friend's place Saturday but he never got it hooked up. He's planning to do it this summer so I'll post some pics when he gets it done.

Paul