My FPH is installed and working!

[riny]

I just wanted to share the news, and to offer a note of thanks to @drglanton for sharing so much helpful info, and to @JamesW for coming up with the "solar impersonation" method.

After many false starts, the installation of my Hotspot "Free Pool Heater" (FPH) was finally finished yesterday. The HVAC guy was able to fit the specialty valves into the body of the condenser unit so it looks very clean. It wasn't an especially warm day but still, we cranked the AC in the house down low and watched it fire up. We pretty quickly had warm water flowing into the pool.

Even the guy was amazed that it worked on the first try. The installation is pretty complex and he said that he expected to get it working "eventually" after some amount of troubleshooting. But as soon as I set the thermostat down, the FPH kicked in and everything just started working.

Attached are a few pictures that show the finished installation. The relay is a 24VAC DPDT relay that switches between a 5kΩ resistor (106°F) and a 20kΩ resistor (50°F) feeding my controller's solar input sensor. There's an actuated valve which opens when the FPH is calling for water, and it kicks my pump up to high speed as well.

We're now at the end of the typical AC season here and will be closing the pool any day, but I'm looking forward to an early opening in the spring. Of course I don't yet have any experience using the thing, but if you're considering getting one and have questions about the installation process, I can do my best to answer them!

 

[riny]

Oh, one other thing I forgot to mention... while the HVAC diagram in the manual is clear and easy to understand, the wiring diagram is anything but. The installer and I both found it highly confusing and nearly impossible to decipher. I ended up redrawing it to be easier to follow and this is what I used for the installation. If you plan to install one of these, you might want to refer to this version.

 

[JimMarshall]

I'm very interested to see how this works out for you. Do you mind sharing (at least approximately) the install cost?

 

[riny]

I'm very interested to see how this works out for you. Do you mind sharing (at least approximately) the install cost?

Not at all. For the 5-ton version, the FPH kit was about $1800. The HVAC guy charged $3700 for the installation and that included everything, although I ended up doing most of the electrical work myself. This is not counting the pool-side plumbing, which I also did myself.

The installation was frankly a lot more than I was expecting, but I just couldn't find anyone to do it. I bought the FPH in May and thought I had an installer lined up in advance, someone I'd worked with before, but he backed out. I had 4 different guys all agree to do the installation and similarly disappear before we could even talk about the price. I think everyone had so much work this summer that nobody wanted to take on a specialty project where they didn't know exactly how long it would take.

By August I just started calling every HVAC company in the phone book. Out of probably 20 calls, I got only one guy who agreed to come and he gave me a written estimate on the spot. I put down a deposit immediately and he's the one who got it done. Based on what I'd heard from other people, I expected the installation to be more like $2000, but at that point I didn't have any other options. He did an awesome job anyway so I really can't complain. The full installation was about a day and a half.

An electric or gas heater would have been less to purchase and install, although I would have needed utility upgrades for either of them and that would have driven the cost up. And the FPH should let me keep the pool at a constant 84° all summer long with no runtime costs, which means we can swim any time on a whim. No need to plan in advance when the pool will be heated and manage the energy costs.

I'm optimistic that it will prove to be a good investment!

 

[Newdude]

Awsome Job Riny !!! For comparison, my heat pump cost $6k installed 9 years ago soup to nuts. (Heater / Labor / electric upgrade to handle it / pad). Then it cost $600-$800 a month to run and had me run out the second month and buy a solar cover which cut the costs in half.

All in yours seems about what I paid (including your time/labor) and you’ll have next to no operating costs. That’s bloody AWESOME!!

Please keep us well updated as you learn the +/-s of it all.

 

[drglanton]

Congrats. Looks great. I’m so excited for you. Keep us posted. Do you plan to turn your FPH system off or just leave it on but mot active because the AC is not on?

 

[riny]

Congrats. Looks great. I’m so excited for you. Keep us posted. Do you plan to turn your FPH system off or just leave it on but mot active because the AC is not on?

I installed it with a pressure switch so after draining the water lines, there's no way for the solenoids to activate. It was still warm enough to use the AC for just a couple of days after closing the pool... when it comes on, the FPH still gets power and tries to pull heat, but the circuit can't be completed without pressure to the switch. So the FPH thinks it's heating but really the AC is doing its own thing.

This works but I don't think it's ideal. I'd prefer to keep the pressure switch as a safety / backup but be able to fully disable the FPH when necessary. For next year, I might add a small toggle switch to interrupt the thermostat lines. If those are cut then the FPH can't get power in the first place.

 

[Nichassur2022]

I just wanted to share the news, and to offer a note of thanks to @drglanton for sharing so much helpful info, and to @JamesW for coming up with the "solar impersonation" method.

After many false starts, the installation of my Hotspot "Free Pool Heater" (FPH) was finally finished yesterday. The HVAC guy was able to fit the specialty valves into the body of the condenser unit so it looks very clean. It wasn't an especially warm day but still, we cranked the AC in the house down low and watched it fire up. We pretty quickly had warm water flowing into the pool.

Even the guy was amazed that it worked on the first try. The installation is pretty complex and he said that he expected to get it working "eventually" after some amount of troubleshooting. But as soon as I set the thermostat down, the FPH kicked in and everything just started working.

Attached are a few pictures that show the finished installation. The relay is a 24VAC DPDT relay that switches between a 5kΩ resistor (106°F) and a 20kΩ resistor (50°F) feeding my controller's solar input sensor. There's an actuated valve which opens when the FPH is calling for water, and it kicks my pump up to high speed as well.

We're now at the end of the typical AC season here and will be closing the pool any day, but I'm looking forward to an early opening in the spring. Of course I don't yet have any experience using the thing, but if you're considering getting one and have questions about the installation process, I can do my best to answer them!

I would like to know is there a service valve on the heat exchange for the refrigerant and do you have any pictures of the wiring. I’m a first year hvac apprentice, I understand the piping and concept but the the wiring is very confusing.

 

[riny]

I would like to know is there a service valve on the heat exchange for the refrigerant and do you have any pictures of the wiring. I’m a first year hvac apprentice, I understand the piping and concept but the the wiring is very confusing.

Sorry I don't have more pictures and everything's closed up for the winter right now. But I can tell you basically how it works. The electrical side seems insanely confusing... so much that I had to make my own wiring diagram which is above in post #2. But once you figure it out, it's actually very simple.

The FPH controller is powered by the Y and C from the thermostat line, so it's only powered when the thermostat is calling for AC. The AC comes on and the controller boots up.

Right away, it draws from the transformer and sends 24VAC to terminal #3 which is the pool contactor. This is used to make sure the pool pump is sending water through the FPH. After waiting a little while for the water to circulate, it checks the temperature and decides whether heating is needed.

When the FPH is not taking heat, the condenser unit is running normally. But if the controller wants heat for the water, then the fun starts. It sends 24VAC from the transformer to terminal #4 which powers three different components: two solenoids to redirect the flow of hot gas, so it goes into the FPH instead of the condenser; and a fan relay which cuts off the fan motor. I guess the fan relay isn't strictly required, but with the condenser bypassed, there's no need to run the fan.

This is the key to understanding how the system works: the path of the hot gas is controlled by two solenoids. When they're off, everything is normal, like the FPH isn't even there. When they're active, the hot gas is diverted to the FPH and the heat is transferred to the water. You could even skip the controller and everything else, put those two solenoids on a switch and run them by hand, and the heat exchange would work just fine. The two solenoids do all of the work, and everything else is just supporting details for the controller.

The last piece, which is optional but really important (IMHO), is the flow switch. If you're using a flow switch, you wire it in between terminal #4 and the condenser components (the two solenoids and the fan relay). This ensures that the hot gas doesn't get diverted to the FPH unless water is actually flowing. If for any reason the FPH isn't getting water... a pump malfunction, leaking pipe, valve in the wrong position, etc... the hot gas will be going into the FPH but without cold water, it won't release its heat and condense. Eventually the unit will overheat and turn off, leaving you with no AC in the house. The flow switch prevents this situation, by making it impossible for the controller to power the solenoids without water flowing.

I hope that helps! Let me know if you have any more questions and I'll do my best. Also I attached the refrigerant-side diagram from the FPH manual in case you haven't seen it.

 

[markayash]

That’s an idea I would love to have. But my outside units are about 30’ away

 

[riny]

That’s an idea I would love to have. But my outside units are about 30’ away

30' from the pool? That's not a problem as long as you can get the water there. The rule is that you always put the FPH as close to your AC unit as possible and bring the water to the FPH using standard 1.5" or 2" PVC plumbing.

My FPH is about 75' from my pool equipment pad and it's uphill. To avoid unnecessary pumping, I use an actuated valve on the FPH water loop. When the FPH activates the pool contactor line to indicate that there's heat available, my pool automation will open the valve and kick the pump into high speed. Then when the FPH turns off, the pump reduces speed and the valve closes.

For 30' you might not need that much complexity though, especially if it's flat. You'd just need some kind of path from your pool pump to the FPH and obviously you'd need to make sure your pump can handle the additional length.

 

[tampapools]

, I can do my best to answer them!

My AC is 64' away from the pool pump.

Did you just dig a trench and bury the pipes yourself? I assume it also requires a wire to be run that length to activate the pool pump on demand.

Any recommendations for variable speed pump? FPH said I needed 2+ hp.

Finally, my ac is almost 8 years old. If the unit dies, I'll need to replace it with the new kind with different refrigerant. Any idea how much of the install costs would have to be repeated to move to a new AC system?

 

[riny]

My AC is 64' away from the pool pump.

Did you just dig a trench and bury the pipes yourself? I assume it also requires a wire to be run that length to activate the pool pump on demand.

Any recommendations for variable speed pump? FPH said I needed 2+ hp.

Finally, my ac is almost 8 years old. If the unit dies, I'll need to replace it with the new kind with different refrigerant. Any idea how much of the install costs would have to be repeated to move to a new AC system?

Yes and yes to your first two questions. I put in my patio at the same time and I asked the crew to dig me a trench before starting since they already had an excavator on-site. I ran 2" pipe up and back for water and a 1" electrical conduit between the FPH and the pool pad. My distance is about 75' and it works just fine.

Sorry I can't recommend a pump. Personally I have a Hayward VS Omni pump with automation and I'm happy with it, but I would get a bigger pump if I had to do it over again. My pump is 1.65hp and it gets the exact right flow rate for the FPH but only on maximum speed. My FPH is on an actuated loop so it runs at low speed when not heating... but still, a bit of buffer would have been nice. This depends on your setup though and I don't think anyone can size a pump for you without knowing all of your details.

As for your last question, I was in the same boat. My installer gave me the option of replacing the AC as part of the job but I didn't want to spend the money on a unit that might still have half its life left. I asked Hotspot this exact question and here's what they said, but you should also ask for yourself if you're concerned:

Yes, it can be done as long as any new unit is same capacity (i.e. tons, btus etc.) and is the same type (i.e. a cooling-only unit or a heat pump) and does not use a variable speed compressor, then the system should transfer over just fine, of course the new unit may need a receiver or a different size receiver, we can calculate that after we know the model number. [When I asked about the valves and fittings:] They can be removed pretty easily with a torch and then re-installed.

 

[tampapools]

Yes and yes to your first two questions. I put in my patio at the same time and I asked the crew to dig me a trench before starting since they already had an excavator on-site. I ran 2" pipe up and back for water and a 1" electrical conduit between the FPH and the pool pad. My distance is about 75' and it works just fine.

Sorry I can't recommend a pump. Personally I have a Hayward VS Omni pump with automation and I'm happy with it, but I would get a bigger pump if I had to do it over again. My pump is 1.65hp and it gets the exact right flow rate for the FPH but only on maximum speed. My FPH is on an actuated loop so it runs at low speed when not heating... but still, a bit of buffer would have been nice. This depends on your setup though and I don't think anyone can size a pump for you without knowing all of your details.

As for your last question, I was in the same boat. My installer gave me the option of replacing the AC as part of the job but I didn't want to spend the money on a unit that might still have half its life left. I asked Hotspot this exact question and here's what they said, but you should also ask for yourself if you're concerned:

Yes, it can be done as long as any new unit is same capacity (i.e. tons, btus etc.) and is the same type (i.e. a cooling-only unit or a heat pump) and does not use a variable speed compressor, then the system should transfer over just fine, of course the new unit may need a receiver or a different size receiver, we can calculate that after we know the model number. [When I asked about the valves and fittings:] They can be removed pretty easily with a torch and then re-installed.

Thanks for the info.... it sounds like I first need to replace my pool pump, and while they're installing it, route the piping to the heat exchanger by the ac, and cap the heat exchanger ac components. Then find an AC installer who's willing to mess with the AC to finish up the other part.

Did your AC guy wire up all the electronics or did you do it yourself (hire electrician)?

Regarding the pool pump, did you want to upgrade the unit so the heat exchange turns the pool pump on low speed instead of your current setup where it has to run at high speed?

 

[riny]

I had a single-speed pump before which wasn't even the right size for the pool. So I wanted to replace it with a VSP regardless. If your AC is 64' from the pool then you're not going to want to pump the water all of that extra distance all of the time. So if you want to do what I did: add a separate loop for the FPH with an actuator. So normally, the pump runs on low speed and the water bypasses the FPH. When the FPH sends the signal that it wants water, the actuator opens and the pump kicks into high speed. My FPH is uphill from the pool pad too, so the pump has to work a lot harder when the valve is open.

When I first replumbed my pad I left the stub for the FPH loop, put a Jandy valve on it, and just kept it closed. Then after I had the FPH hooked up, I replaced the valve handle with the actuator. The return has a check valve on it so that didn't need any change.

I did all of the pool-side plumbing and electrical work, and all of the connections in the FPH box. My HVAC installer did the electrical work in the AC unit.

 

[gsgorsuch]

Thanks for the info.... it sounds like I first need to replace my pool pump, and while they're installing it, route the piping to the heat exchanger by the ac, and cap the heat exchanger ac components. Then find an AC installer who's willing to mess with the AC to finish up the other part.

Did your AC guy wire up all the electronics or did you do it yourself (hire electrician)?

Regarding the pool pump, did you want to upgrade the unit so the heat exchange turns the pool pump on low speed instead of your current setup where it has to run at high speed?

Did you find someone to install for you? I am having trouble getting the company Hotspot recommended to commit to a date & time to come out!

 

[Jersey Cowboy]

Hi Riny. I have been researching this and very interested in installing.
Can you give contact info for the HVAC company who was willing to do it?
I'm not too far from Poughkeepsie.
Seems like the hardest thing about this is finding people to install it...

 

[riny]

Hi Riny. I have been researching this and very interested in installing.
Can you give contact info for the HVAC company who was willing to do it?
I'm not too far from Poughkeepsie.
Seems like the hardest thing about this is finding people to install it...

You're right about that! I'll send you a PM with the contact info.

 

[Newdude]

Seems like the hardest thing about this is finding people to install it...

It's a similar cross pollination as a heat pump. The electrician says it's a plumbing problem and the plumber says it's an electrical device. The HVAC guy, who is fully qualified, says 'I dunno man, your PB installed it, go see him'. The PB tells you to call an electrician...........

 

[tampapools]

There's a local company who does pool installs, but also boasts about having licensed HVAC specialists on their staff. I thought "perfect!"

But they immediately said they weren't interested when I called their pool department, so the next day I called for the HVAC side and they said the same thing.