A good and enterprising fellow inflatable spa owner in Sacramento named Mike, was kind enough to to send me some details on his Franken-Spa creation. It is completely independent of the spa's own heat/filter control unit, drawing water from the drain. He does not have the winter challenges/temps that I do in Toronto, but I think the EcoTemp propane shower heater would do the job up here as well. I may just do it, but perhaps next year.
Here is Mike's description of the setup (in addition to the details I provided a link to in post #7);
Thanks Mike!
Here’s the pic of my modification. The intex filter/pump was being flakey when sending water to the propane heater. It might be a problem with my pump, or a problem with that type of pump. Other forums suggest a transfer type pump with inline filter. I added a small pump to the water outlet leading to the propane heater, and now it works great.
There are three hoses connected to the heater:
-water line in (black)
-propane line from canister (also black)
-water line out (silver shower head line, nothing connected to it in the hot tub)
I put a cover over the hot water outlet in the tub. The water coming out of the propane heater line can be pretty hot, so best not to come in direct contact with it while in the spa.
Disclaimer: I am not recommending anyone make modifications to their Purespa system, just showing what I’ve done.
Mike
PS – several other pure spa owners have recommended insulation foam boards under the spa, on top of the cover, and or floating thermal blankets to improve efficiency and usability of the spa, especially in colder weather. I added a 6’ diameter R13 foam board to the top (just laid it on the cover and weighted it). It looks like it cut my electricity use in half.
I ended up pulling the inflatable portion of the lid out of its cover, and now cover the spa by putting the inflatable top on first, lay the foam insulation board on second, and then tie the whole thing down with the fabric cover that attaches to the tub. Much better at holding in the heat.
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