Good points, had not given consideration to the potential low flowrate whilst just on a filter cycle, mine has a two speed pump, will check the flowrates via the manufacturers datasheets.
From my understanding with the Balboa system you keep the heating element in place as it has sensors at each end of the heater tube, but you disconnect the heater plug from the PCB, i've seen two configurations, either using the Balboa PCB to power the heat pump, not prefered option imho, or power the heat pump standalone which is probably my prefered option.
Will do some more research and update here if i go ahead.
2 speed pumps can be a pain if you're trying to pair it with a heat pump. The low speed will generally be between 0.25 - 0.75 hp, whereas the high speed will be between 1.5 - 3.0hp. You'll need to source a heat pump that will work happily with either of the 2 different flow rates, but that means neither will be at the optimum rate for your heat pump so it won't be working as efficiently as it could.
Regarding the fault codes and wiring, as far as I can remember, and from a quick look in my Balboa service books, disconnecting the heating element won't throw a fault as it doesn't look for a current draw or a temperature differential across the sensors to confirm the element is working. For the wiring I'd definitely install the heat pump on its own supply. I can't think of a pool heat pump that I've installed that doesn't have a flow switch in it, so it'll only try and heat when the hot tub is circulating.
Thanks, will take this into account when i look around / before buying something, my understanding of what the Balboa system will do is the same as yours, which is reassuring!
Given your experience, any recommendations on invertor heat pumps brands in the ~5 - 9kW output range (ignoring the flow rate requirements)? I'm after something reliable / efficient and low noise!
Out of the ones I've installed I think the only brand that offer sub 10kw output options are the Poolstyle Step Inverter heat pumps. I've installed quite a few of these, albeit larger output ones on swimming pools, and they appear to work well and get good feedback from our customers.
Not yet the cost to run a hot tub goes down month on month at this point in the year. We don't regret having one at all as the benefits outweigh the cost and its practically free to run over the summer anyway. (Solar Panels)
Inflatable hot tubs seem to use up 100% more electricity and lose heat over twice as fast as a proper insulated rigid hot tub. Inflatable seem like a cheap option but if its up all the time, long term they cost more then a insulated rigid hot tub. A couple of degrees overnight with the heater off is a lot to lose in the summer. My rigid hot tub loses less then that in the autumn/spring yet alone the summer.We're going to leave our inflatable one stowed in the garage until high summer. In high summer it only needs a couple of hours to bring it up to temperature and the high overnight temperatures mean it only loses a couple of degrees overnight with the heater off. Using it in spring and autumn is a different story, with the heater chugging away for hours on end.
Last summer we really enjoyed the hot tub and were considering getting a rigid one. The cost of electricity has put the kibosh on that.