Hotspot FPH AC heat reclamation pool heater - a review!

Joshii

Well-known member
Jul 15, 2013
240
This is my fourth season with the FPH and I have not had to have any technician touch my AC in all that time. Still works great.

(but now I jinxed it for sure)
 

nuttyp

LifeTime Supporter
Nov 23, 2014
12
Naples/Florida
A couple folks asked me if my FPH is still working. hence a quick update: It was still working fine after three years of use, then I sold the home. I learned later that the new owner replaced the AC system, so I presume he tossed all this out, or sold it :-( I have a new place now with larger pool and conventional heater but I don't think I'll deploy another FPH because I'm never sure I'll stay in one place long enough to get the ROI out of it. That said, I may look into EricDu's DIY suggestion pposted above, thanks Eric, although the link in that post seems no longer valid.
 

nuttyp

LifeTime Supporter
Nov 23, 2014
12
Naples/Florida
I know this thread is old, but a question came directly to me this week (November 2019), so I post the answer below, for the benefit of others in the forum.

Q: Hey! I was wondering if you could recommend someone to install the hot spot heat exchanger. I'm in Orlando and struggling to find a contractor that will do it. Thanks.

A: The sales folks at FPH have also contacted me once or twice over the years to see if I know anyone in the area, but I don't. Perhaps I was lucky in that both of the first two A/C contractors I contacted were willing to do the job. It may have helped that I was very detailed in what I asked of them. For example I made it clear that I would have others handle the pool side controls and PVC portions, and I only needed the HVAC guys to handle the valves and refrigerant connections involving the condenser unit. I also provided them with all the instructions from FPH and gave some guidance along the way. So I did all the PVC and low voltage controls, water temp sensor stuff, etc., myself - but I believe any experienced pool tech company could do that portion. I think I also let the HVAC guys know that I was not expecting them to warranty the work, so long as they installed the valves and connections per instructions and with no leaks. The HVAC guys didn't think it was that big of a deal, but did require working at their hourly rate because they were unsure how long it would take. My final project costs outline is pictured below, if it helps.

Good luck! Joe

PS While I was always fond of the FPH and the results, there is always the matter of modifying the current A/C condenser unit, voiding the warranty and confusing subsequent repair folks. In my current home I'm considering this instead: SolarAttic | Home Page | The New Fourth Generation Solar Pool Heater

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drglanton

Bronze Supporter
Apr 11, 2020
80
Atlanta
Thanks for the writeup, I am considering adding one to my pool. We will have a gas heater for the spa and when the weather drops too much but this FPH hotspot heater looks very interesting to me.

I live in north atlanta, and we run the AC all the time. I think this would work great in april/may and september and october, and because our pool is very shaded. I dont like very cold pools!

Are you still happy with the system? How about a several year update!!

Do you have the ability to set it to a water temp setpoint so it doesnt keep heating the pool?

Would you install it again?

I may just do a Jandy HEatpump/Chiller Combo.

Any idea if its resulted in any cost savings for you in you HVAC bill? Looks like "free heat"


thanks!
Hi - I too live in the Atlanta area. Did you decide to go with the install?
 

drglanton

Bronze Supporter
Apr 11, 2020
80
Atlanta
Total cost was $4,000.

I was eager to share with you my experience with the install and operation of this pool heater, as there is a lot of interest out there, a lot of theories of whether it will work, whether it will heat the pool at all, or overheat it, etc, and virtually no reviews of an actual install out there. I hope this helps some of you who may be thinking about installing such a system for your own pool. I would not hesitate to do so again. Every time I see an AC unit spitting perfectly good warm air into the sky I think what a shame, it could be put to such good use.
[/QUOTE]
We do run the AC a lot here, even in winter (I had home heat on for a total of 20 minutes last winter), so I solved the issue of the pool pump running a lot by dropping an additional $1K on a variable speed pump. With a 1 speed 220 volt pump you use the FPH control's 2-pole relay to send 220 to the pump (in parallel to pool timer, careful to not cross the poles or have electrician do it), and now with the variable speed pump it only uses one pole of the FPH relay - closing the remote contacts feed from the pump controller to tell the pump to come on. That's nice to ensure the pump comes on, but now I just run the pump 7x24 anyway, in 1200 RPM / 72 Watt mode, a savings there as well (although break even on the $1K pump is probably 4 years, assuming it lasts that long). As others alluded, there is a minimum flow rate to ensure the exchanger is cooling properly, I checked that but don't have the numbers handy. The pump is 50 feet from the AC & FPH exchanger, I ran 2" from my 1.5HP max pump.
I would love to ask you some questions about this. I am installing a new building and considering the FPH with a variable pump. Are you using Easy Yoouch or Intellicenter? What is the brains of the systems? I have so many questions.
 
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drglanton

Bronze Supporter
Apr 11, 2020
80
Atlanta
Does anyone run the FPH with automation? I have a Pentair VSP pump, and Hotspot said the FPH must control the pump via the automation port, so my Intermattic z-wave system won't be able to control it. I would love to hear if anyone uses this thing with automation.
I'm looking at buying a separate pump for the FPH and circulation, but don't know how I would plumb two pumps.

Sent from my Nexus 9 using Tapatalk
DID YOU GET AN ANSWER TO THIS QUESTION? I AM WONDERING THE SAME THING. DID YOU GO WITH THE SYSTEM?
 

drglanton

Bronze Supporter
Apr 11, 2020
80
Atlanta
Since I am in the process of hooking up the system, I am looking for any photos of completed installations. If you can share, and this site allows, I would appreciate it.

Thanks!
HOW DID YOU BUILD COME OUT? DO YOU HAVE ANY AUTOMATION? DO YOU HAVE ANY PICTURES TO SHARE?
 

drglanton

Bronze Supporter
Apr 11, 2020
80
Atlanta
If you have automation like the ET, it can handle the exchanger without the Brains of the Hotspot. I called CS at Hotspot and explained them what the ET does with solar and its basically a relay that opens a selenoid, which can do the same for the AC unit. This means that the refrigerant will only flow to the exchanger when ET calls for heat and operates the Pump to circulate water. So you can save some $$ if you have ET.
WOW! THIS IS WHAT I HAVE BEEN SEARCHING FOR!! How is the ET or the IntelliCenter working with the FPH? This is what I want to do.
 

kmheid

New member
May 21, 2016
4
Aurora
DID YOU GET AN ANSWER TO THIS QUESTION? I AM WONDERING THE SAME THING. DID YOU GO WITH THE SYSTEM?
I did install the FPH. I do not let it control my VSP pump. I generally let the FPH run all of the time. I can disable it and control the pump with my Intermattic z-wave system if I want to turn it off. It works well most of the time. I should have installed a flow switch to kill the FPH if there is a problem with the pump.
 

drglanton

Bronze Supporter
Apr 11, 2020
80
Atlanta
I did install the FPH. I do not let it control my VSP pump. I generally let the FPH run all of the time. I can disable it and control the pump with my Intermattic z-wave system if I want to turn it off. It works well most of the time. I should have installed a flow switch to kill the FPH if there is a problem with the pump.
What do you mean works well MOST of the TIME> Why have you chose not to use it with your VSP?
 

nuttyp

LifeTime Supporter
Nov 23, 2014
12
Naples/Florida
A member direct messaged me asking about what I used for brains & automation in my FPH system – I thought I would share this update in case it’s useful for others…..

I'm not sure if you managed to read all that was posted across what now seems to be eight pages of posts to this FPH review article, it is a long read :) But I did post back to this thread with some amount of detail about the brains, and I also noted that I had the FPH for about 4 years before I sold that home in 2017. So I don't have it anymore, but in my present home I wish I did, and may still buy another one at some point.

In any case I loved the FPH, it worked well for those years. The brain was mostly as supplied by the FPH folks - a "PID" that you set to desired temp., then it senses pool temperature and drives some relays, some that are internal to the FPH control box and other relays and valves that must be installed in the AC condenser unit. (A relay added to the condenser unit also feeds back to the FPH to tell the FPH controller that the AC is running). The PID used by FPH is only to sense temp and close a set of contacts to drive those other relays, and in my opinion the one chosen by FPH was overkill. I wanted to "remote" the temperature display and set points from inside the home so I wired in a far simpler version for $15 from ebay, similar to this one: 10A 110V Digital Temperature Controller Temp Sensor Thermostat Control Relay US 708624426335 | eBay
I can look for the exact one if you want. I had it wired so that I could use the outside FPH controller or my indoor ebay one, but eventually the FPH PID failed so I just continued using my indoor ebay cheap controller.

Not to digress but.... Selecting the cheap temperature controller got a bit tricky. First you can choose a Fahr. or Cel. controller, then choose whether you'll drive it with line or low voltage. I chose line voltage and mounted it in a standard switch box, then made a smoked plexiglass plate as a bezel to screw to the box. Programming it was a bit nontrivial - not rocket science but a bit tricky to get it to only close contacts when temp fell below setpoint. I recall it was rather counterintuitive, where “off” was on and “on” was off (relating to the contacts) but it worked fine. Also the type of thermocouple used by the FPH (back then) was not compatible with the type used by these cheap controllers. Accurately sensing water temperature is a pain in all systems, it seems to me, especially if water is not always flowing, sun shining on the sensor at the pipe, etc. I’m now thinking the only good solution for that is a very long wire leading to the overflow pipe and down and back up into the skimmer enclosure. Sheesh.

Back to the brains.... One of the FPH relays is made for high current so it can drive a full speed 220V pool pump, and as I wrote in the thread I used that for some time, then I added a variable speed pump (VSP). That VSP was a Jandy with its own speed controller, and I rewired the FPH control high current relay contacts to just close contacts that are inputs to the Jandy VSP controller. The net of all that is the ‘logic’ that is nearly always the same: when the FPH calls for pool heat, and if the AC is on, the FPH closes a relay to tell the pump to come on and drives a relay in the condenser cabinet to switch refrigerant to water cooled mode, while driving another condenser cabinet relay to turn off the cooling fan.

For folks with other "brains" / automation systems I'm sure you could bypass some or most of the FPH controller relays and functions so long as your automation system is capable of closing contacts to control a heater, then it's just some wiring choices depending on how automated the brain system is. For example if the automation system drives the pump, senses temp., drives relays with adequate current, then you would need very little of the FPH control cabinet. But I suppose even the most sophisticated automation systems don’t sense whether the AC is on, so it might make sense that the automation system’s relay drivers should be wired in series with the relay that senses “AC on” so that water cooled mode is only activated to switch refrigerant when the AC is on. It can seem tricky, but not too bad when you think it through. Others also alluded to using whatever brains to also drive water valves. Sure – but in my case I just let the water always circulate through the FPH exchanger.

Happy free heating to all !
 

cdstock

New member
Apr 23, 2020
1
Louisiana
This is my fourth season with the FPH and I have not had to have any technician touch my AC in all that time. Still works great.

(but now I jinxed it for sure)
You're several years ahead of me. I just found out about this option a couple of week ago, and I have been kicking myself for not being the one to think of it before.

Is your system still running well? I've been contemplating replacing my AC system too since it is ancient itself. ~25 yo evaporator.
 

Joshii

Well-known member
Jul 15, 2013
240
You're several years ahead of me. I just found out about this option a couple of week ago, and I have been kicking myself for not being the one to think of it before.

Is your system still running well? I've been contemplating replacing my AC system too since it is ancient itself. ~25 yo evaporator.
Yup! Fingers crossed it is. Still too early up here for AC, but it was working perfectly at the end of last season.
 

drglanton

Bronze Supporter
Apr 11, 2020
80
Atlanta
This is how the company has explained the system:

When the AC (or heat pump) unit comes on (based on your indoor thermostat) there is a sensor that lets the system controller know it is on. The controller then starts your pump by communicating with an automation relay on your pump or if you use a mechanical timer, by using a contactor to override the timer, or interface with a variable speed pump. This action starts the pump if it is off, or if it is on, it keeps it on. The pump runs for ~25 seconds to flush the pipe and cure any dry pipe condition, then by using a sensor the controller samples the water temperature. If the water temperature is below the set point that you have selected in the controller, heat recovery is activated. If the pool is warm enough based on your temperature target, the pump is released back to its normal control and the controller resets.

When heat recovery is activated, the heat recovery valve is activated and the AC unit switches from using the normal air-cooled condenser and begins using the FPH titanium heat exchanger/water cooled condenser. At this point all of heat goes into the pool, and the condenser unit fan is deactivated by a relay. Also in this process, any refrigerant that was left behind in the air cooled condenser at the time of switchover is pumped out to the suction line through a meter valve that prevents liquid from entering the compressor. The pump-out procedure keeps all of the refrigerant on the active side of the system. When heat recovery is disengaged, the condenser fan operation is restored and the heat recovery valve(s) switches back to using the air cooled condenser. At this time the FPH water cooled condenser is pumped out to suction in the same manner explained before.
 

drglanton

Bronze Supporter
Apr 11, 2020
80
Atlanta
For folks with other "brains" / automation systems I'm sure you could bypass some or most of the FPH controller relays and functions so long as your automation system is capable of closing contacts to control a heater, then it's just some wiring choices depending on how automated the brain system is.

Happy free heating to all !
How do you run your pump when the FPH system has not called for heat? Is it just using the schedule of the timer/automation?
 

Joshii

Well-known member
Jul 15, 2013
240
There's a number of ways to do this.

If you have a single speed pump, you can have the FPH controller turn it on when it needs to. When it ISNT calling for heat, the pump timer will turn it on/off.

Another way is to keep the FPH controller on a timer, and overlap times-of-day when the FPH can POSSIBLY call for heat with when the pump is running.

Another way is to use your pump's automation settings. I have a superflo, which can take in pin-lead voltages to set its running - a simple automation system that doesn't require any additional fancy controller. I've been thinking of using the 24vac on the FPH controller and hooking that into one of my pump's automation pins to have it turn it on when needed.

Tons of options.
 
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drglanton

Bronze Supporter
Apr 11, 2020
80
Atlanta
I am trying to figure out how to have my Pentair Intelliflow VSP respond to both the FPH Conrtrol (2 wires (+/-) at 24vac) and the Intellicenter which uses a RS-485 communication cable provided with the pump and will be used to connect the pump to a Pentair automation system.
If I figure out how to have the ONE pump come on when FPH calls for it and when the Intellicenter calls for it - - I will be perfect!
 

Joshii

Well-known member
Jul 15, 2013
240
I am trying to figure out how to have my Pentair Intelliflow VSP respond to both the FPH Conrtrol (2 wires (+/-) at 24vac) and the Intellicenter which uses a RS-485 communication cable provided with the pump and will be used to connect the pump to a Pentair automation system.
If I figure out how to have the ONE pump come on when FPH calls for it and when the Intellicenter calls for it - - I will be perfect!
The intellicenter ought to be able to take in standard control signals. I believe there's an adapter for it. Maybe one of our members that has this pump and that automation system can help.