bathing electrical safety with a non-pool pump

[bricktron]

hi folks, to keep water temperature nearly constant at a low level of noise, i want to pump continually, at just a couple of GPM. i have done the math on the temperature of water coming out of my small gas heater and the PVC should be fine. pool pumps are generally way too big for this application - i want something in the 1/10 HP range to achieve maybe 4 GPM with about 9 feet of head. i have been reading about hot water circulation pumps (grundfos, taco - grounded but not rated for outdoor use), aquarium and fountain pumps (eheim - immersable but with a warning to unplug before touching the water). does anyone know whether there is an increased risk of shock to bathers when using alternative kinds of pumps?

thanks in advance for tips.

 

[danpik]

None of this makes any sense from an efficiency standpoint. The best way to run a heater is to push as much water thru it as possible. Too low of a flow and the BTU/hr going into the pool will drop off to the point that the heater will not keep up with the heat loss. The temp rise of the water going slower thru the heater will not rise in a linear fashion. At a couple of gallons/hr, the heater will most likely overheat and shut off on high limit as well. As far as pumps go, you will need to connect any pump ypu use to a GFCI outlet. If you insist on doing this, at least spend the money and get a hospital grade GFCI.

 

[bricktron]

thank you danpik for responding. your point on efficiency is well taken, though i don't understand the physics of it, but efficiency is not my main concern, it's noise and temperature regulation. too many times i have been in hot tubs whose pool-sized pumps were audible from the tub, or whose temperature varied too much while the pump was off. i think running a small pump continually will address these issues.

a couple of GPH would be too little. i think a couple of GPM may be enough.

i will use a GFCI socket. thank you for making that explicit.

 

[bricktron]

here are two suggestions i got elsewhere: power the pump through an isolation transformer; or use a low voltage DC pump. some combination of these is going to work.

 

[Isaac-1]

The simple solution here would seem to be to use a hot tub circulation pump like the Hot Spring E5 pump

 

[bricktron]

thanks for the tip isaac. i hadn't thought of trying a pump used in an all-in-one tub. this one seems a little small for my 9' of head, but the premise could work. cool deal.