Gas Heater Connected to Retail Spa

[rob.mwpropane]

Good day all. I have been scouring the internet for some time looking for ways to tie a hot tub into an already existing 400K BTU pool heater. I can't find any examples. If anybody could post some links, or pm me if that isn't allowed.

I've seen the ones where it's a custom build and it gets plumbed in with everything else, however I'm looking for a retail hot tub "T"d into the system. Like a couple valves and maybe the pool pump running water into "T"'s inline with some more valves? I hope this makes sense. There is a chance I'm just not Goggle-ing the correct term.

Thanks to all.

 

[rob.mwpropane]

Anybody? I know it can be done, but rather than do trial an error, I'd like to hear from someone who's done this? I'm sure someone hear has gotten rid of that horrible heating element under there for something that costs less to run? I know I watched the meter fly when I had an electric water heater for the house....

 

[gilbee]

I see no problem with this...only issue may be if you can get adequate flow through the heater so as to keep it running, but I don't think that would be problematic. Other than seeing others who have done this, what are you thinking would be a problem? I'm thinking that each tub would be different so even seeing pics of someone else do it wouldn't necessarily help you. If you already have the heater, shouldn't be too hard to cobble this up...

 

[rob.mwpropane]

I was really just thinking out loud. I have the pool, and a heater, and am looking for a descent hot tub. I see they have anywhere from 1-3 pumps in them. I don't know if I should remove one of the pumps and just use the pool pump, or keep all and have a primary loop that feeds the spa? I was taking a look at one yesterday and I just couldn't get a great idea how to do it.

Now that I'm writing about it, I think the best bet would be to remove one of the pumps, and use the pool pump in its place to move heated water through that loop. Without really tearing things apart, I don't see how I can just add the heater....

 

[gilbee]

My only thought would be what kind of plumbing is in there and if it can take the pressure...since you'll probably have more distance from the pool pump you should probably be fine, but that's the only thing I think could bite you...

 

[rob.mwpropane]

My only thought would be what kind of plumbing is in there and if it can take the pressure...since you'll probably have more distance from the pool pump you should probably be fine, but that's the only thing I think could bite you...

See, that's something I wouldn't have thought of. My pool pump was way oversized the way it is, so I guess that's about out of the question.

 

[gilbee]

Maybe not---just check to see if you have flex tube or pvc...knowing the old pumps hp would be a good metric to know as well...

 

[rob.mwpropane]

Ok, so I've been playing with ideas in the back of my mind and I think I've come up with something. We have hooked up boilers at my work and I have a very limited understanding of primary loops and secondary loops. If I was to put a "T" in line for the primary loop to run (this would be "out" to pool heater) and a second "T" downstream of that within 12", just like a boiler (this would be "in" from pool heater) there would be no excessive pressure buid up, and the pumps from the hot tub could be on or off with no effect. If the pool heater reached the set temperature, it would just shut down. Of course, the pool pump would still be running the primary loop.

My only concern would be if this would cause the pool heater to short cycle? Anybody have any input? Thanks.