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Author Topic: Outdoor Boiler used to heat hot tub?  (Read 2989 times)

engineman1714

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Outdoor Boiler used to heat hot tub?
« on: August 09, 2011, 03:32:11 PM »

Hello,

I have tried to find out more information online about heating a hot tub with an OWB but I didnt find much. I'm sure it can work but I am wondering on the heat demand of the hot tub. I also don't see many people using it for this application.

I would be using a CB 6048 to heat domestic hot water 65 gallon side arm, 3000 square foot insulated house and the hot tub. Winters here can drop to -25 at night.

My bad if this ? has already been asked, I did try to search for my own answer.
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RSI

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Re: Outdoor Boiler used to heat hot tub?
« Reply #1 on: August 09, 2011, 04:47:41 PM »

Yes, it can be done.
Will you be heating it during the winter? Is this the first year you had the boiler? If you have had it for a while you should have a pretty good idea if how much extra capacity it has.

I would recommend only using a tube in shell stainless heat exchanger. Some people may say to use a flat plate but the plates are so close together they can easily plug if you get anything in the water. Also, they are braised together usually and the chemicals in the water might eat the braising.
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It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so. - Mark Twain

engineman1714

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Re: Outdoor Boiler used to heat hot tub?
« Reply #2 on: August 10, 2011, 12:09:37 AM »

This will be the first year, and yes I was hoping to heat the hot tub in the winter, although it might not be hooked up this winter. Just the house and hot water. The house will be using radiant heat.
Thanks for the advice.  How big of a heat exchanger for a ~400 gallon hot tub?
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koutsman

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Re: Outdoor Boiler used to heat hot tub?
« Reply #3 on: August 10, 2011, 07:32:35 AM »

Engineman,
                 Talk to Blaine at Wood Boiler U.S.A. They manufacture boilers down by Indianapolis, In. They have a hot tub kit you can buy that works great! I installed it last Dec. and it works great. I'm heating 5000sq. ft. of house and garage, 2-50 gal .water heaters and my hot tub. When we added  the hot tub we didn't even notice a difference in wood consumption!! It's great!
Call Blaine at 1-888-786-8703.   He even has a diagram how to do the plumbing. You will not be disappointed.

                                                                                                                                                                               Koutsman                       

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dirtryder

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Re: Outdoor Boiler used to heat hot tub?
« Reply #4 on: August 12, 2011, 08:34:41 AM »

Yes and it is great. I notice no difference in wood usage. I heated 2 winters with a HE5000 wood doctor but now I have a CB6048 .  Hooking up my pool to it in about 2 weeks (when pool is done).
Here is the post I wrote and a link.

Yes I do and it works like a charm. I have a water to water HX installed in my return line to my tub right before it enters the tub. This way, all the other components of the tub, like heat probes flow sensors filters........really don't know the HX is there. I have boiler water coming into the HX with a 3 way 24V taco valve. I have 2 modes of heating my tub, electric or wood via a dbl pole dbl throw (on-off-on) 50 amp switch (looks just like a wall light switch) mounted to my tub skirt. You need to find which 110 hot lead to the heater shuts off when the tub stops calling for heat. This is on a 240volt heater and tub. Take that wire off the heater and run to switch. Take "wood" side of switch to a 24 volt transformer, run the "elec" side of switch back to the terminal of heater element.  Now, when the tub calls for heat, either the 24volt transformer wire  (which opens 3way valve to allow boiler water into HX) becomes hot, or the element like normal works, depending on what I'm heating with. With no power to wire (tub up to temp) the 3way valve goes into "bypass" and no boiler water goes to HX. My tub has a 24/7 circulator pump so it works perfectly. It sounds complicated (especially me trying to explain it) but it really is not. I did all the work myself. My tub holds 480 gal of water.
70K Hot tub HX  $319.00  (make sure it can take chemicals, that's why so expensive)
1"  3way 24V Taco valve $89.00 (e-bay)
Underground pex  left over from install but calculated when purchased
50amp on-off-on switch w/ outdoor mounting box  $95.00  (special order from electrical supply)
2- 20 amp ground fault breakers for OWB circ pumps $30.00ea. ..........I figure a very "remote" chance that one of my circ pumps would short and "electrify" my boiler water which in turn would "electrify" my hot tub.....not a good thought so ground fault breakers on pumps will eliminate that scenerio. I would HIGHLY suggest this.

Any questions just ask away.


http://outdoorwoodfurnaceinfo.com/forum/index.php?topic=177.msg2580#msg2580
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boyland

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Re: Outdoor Boiler used to heat hot tub?
« Reply #5 on: August 25, 2011, 07:18:49 AM »

Thanks Kout for the reference.

You can ask for me(Blaine) or Laura.

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markamx

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Re: Outdoor Boiler used to heat hot tub?
« Reply #6 on: September 14, 2012, 08:04:45 PM »

hi, i have a heat source boiler i would like a diagram on how to hook up my 6 person hot tub i read your ost but any type of digram would be greatly appciated thanks for any info mark
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