I also purchased a HotSpot FPH heater. I found an HVAC installer that was willing to do the work, a smaller family owned company. Unfortunately they didn't follow the instructions provided and decided to do it their own way. The first warning sign was that they didn't install all the provided parts, saying that they've been in the business longer and know better....
Anyway it worked for a month or so. Then one day the AC stopped working. The outside compressor had blown a breaker. I started it up and the refrigerant line ruptured and the scroll compressor blew out. Luckily the compressor was covered under warranty. The installer came back and de-installed the FPH and de-modified the compressor and it's been running fine ever since.
When it was working, it was great, it heated up my 30,000 gallon pool to 89 degrees F. Like jblizzle says above, it's really only good for summer when the AC is running. I purchased a Heat Siphon pool heater which has been working well even during the winter.
I still believe that the FPH is a good product but as with any HVAC installation, it must be done by an experienced professional. I still believe the problem lay with the installer deviating from HotSpot's instructions. I had asked them what would happen if the pool pump stopped while the FPH was in 'heat recovery' mode and they claimed that a flow switch wasn't necessary, as the low/high pressure switches in the heat pump itself would shut off during overheat. I think that the way the FPH was plumbed in was the cause of the failure.
If anyone is interested in my FPH-HP (heat pump variant), i'm selling it for $500. The heat recovery valve needs to be rebuilt as does the control box (which my HVAC installer gutted, for no apparent reason). All the parts are there but it needs to be wired back up. Send me a PM if you're interested.
Welcome to TFP!!!