Hotspot energy FPH install

[coopersguy]

Looking for installation advice. Just purchased the HOTSPOT Energy Free Pool Heat System. Directions require engineering degree and extra brain cells. Conventional HVAC, VSP.... Intelliflow. Hotspot said I don't need to connect the system to my VSP as it is electronic but now at a loss on how to connect and ensure it works properly. What do I need in terms of making it easier to turn off and on since it is not connected to my VSP? How do I power the control panel if its not connected to my VSP? Does anyone have better drawings, schematics, directions for connecting the wiring? Tips, Tricks etc? Thanks for all your help!

 

[JoyfulNoise]

If you search “hotspot FPH” the first three threads returned have lots of details. I would read through that and then contact the OPs to see if they’re still around on the forum.

Google search results

www.troublefreepool.com

 

[Maverick23]

The hotspot system is controlled by the 24vac off your hvac system. It has a relay that can turn on a pump to ensure water is circulating.

I think you would use the relay on the hotspot controller to send a signal to the vsp or the relay panel to change the pump speed.

 

[nuttyp]

As Matt (@JoyfulNoise) states, there are tons of tips and explanations across hundreds of posts in those search results, all worth a careful read-through – or two (three?) read-throughs

In those many threads I’m not sure we ever summarized it well. So here goes: The supplied FPH controller does a few things. First it senses whether your HVAC is running by means of the 24VAC from the condenser unit contactor, as @Maverick23 states. And of course the FPH controller also senses your pool temp. The FPH controller also has a heat temperature setting in a PID controller (it’s really just an elaborate thermometer with relay contacts). If your HVAC is running and the PID temp setting calls for pool heat, the FPH controller does a few more things: First , it sends it’s own source of 24VAC back to the condenser unit to turn off the cooling fan and switch the refrigerant path to bypass your HVAC air cooled condenser coils and condense refrigerant through the new FPH heat exchanger. Under those conditions, the FPH controller also activates a relay to send 220Vac to a standard single speed pool pump (could be 120 or 240V). There are at least three ways to modify the wiring to drive a VSP. If you don’t want to modify the FPH relay wiring, you could add another relay that closes a pair of dry contacts when it gets the 120v (or 240) from the FPH relay. Those dry contacts then tell the VSP to come on and I believe most or all VSP’s and automation systems offer the dry contact sensing. The 2nd way, what I did when I first added a VSP, is to modify the FPH relay so that instead of sending 220v to the pump, that rewired relay became the dry contact closure device, using only one pole of that FPH relay to do so. In the end however, I just ran my VSP 7x24 on a low speed. But, as I documented in later threads, the 24Vac sent back to the hvac system should first be wired through a pressure or flow switch, so that the refrigerant path only switches to the FPH heat exchanger when there is true water flow. Back when I implemented, FPH ignored flow which leaves you vulnerable to AC failure (compressor overheat/overpressure) if the pump fails to start, which in my experience VSP’s are prone to do. But all pumps fail at some point, so logic is needed to keep the hvac from switching to FPH if flow is not happening. They also sell inexpensive delay modules that might also be a good addition to that flow path, so that the pump has time to prime and fully create flow before switching the refrigerant path.

It's not rocket science but it is nontrivial, best handled by an electrician and/or pool pump person with similar knowledge or experience, at least for the pool/pump interfaces. More difficult is the installation of the sporlan refrigerant valve and check valve(s) that are brazed in place to reroute refrigerant. That requires an epa608 certified hvac tech to remove/recover current refrigerant, install the sporlan valve and, as necessary refrigerant check valve(s), then re-charge refrigerant and test all functionality. For some of us, finding an HVAC tech willing to do that work can be the toughest part (think of a tech familiar with “heat recovery” systems). When found, that tech will want to work hourly and they likely will need to speak with FPH experts about check valve dependencies and such, depending on your hvac design. Back when I did it, I learned enough to be the go-between interface between FPH techs and local HVAC tech – and I had a very good hvac tech. Somewhere in all those posts I included what it cost me for all that, including tech labor.

I think most of us got all that worked out before buying the FPH, but I applaud your gumption if you just dove in!

 

[Maverick23]

As Matt (@JoyfulNoise) states, there are tons of tips and explanations across hundreds of posts in those search results, all worth a careful read-through – or two (three?) read-throughs

In those many threads I’m not sure we ever summarized it well. So here goes: The supplied FPH controller does a few things. First it senses whether your HVAC is running by means of the 24VAC from the condenser unit contactor, as @Maverick23 states. And of course the FPH controller also senses your pool temp. The FPH controller also has a heat temperature setting in a PID controller (it’s really just an elaborate thermometer with relay contacts). If your HVAC is running and the PID temp setting calls for pool heat, the FPH controller does a few more things: First , it sends it’s own source of 24VAC back to the condenser unit to turn off the cooling fan and switch the refrigerant path to bypass your HVAC air cooled condenser coils and condense refrigerant through the new FPH heat exchanger. Under those conditions, the FPH controller also activates a relay to send 220Vac to a standard single speed pool pump (could be 120 or 240V). There are at least three ways to modify the wiring to drive a VSP. If you don’t want to modify the FPH relay wiring, you could add another relay that closes a pair of dry contacts when it gets the 120v (or 240) from the FPH relay. Those dry contacts then tell the VSP to come on and I believe most or all VSP’s and automation systems offer the dry contact sensing. The 2nd way, what I did when I first added a VSP, is to modify the FPH relay so that instead of sending 220v to the pump, that rewired relay became the dry contact closure device, using only one pole of that FPH relay to do so. In the end however, I just ran my VSP 7x24 on a low speed. But, as I documented in later threads, the 24Vac sent back to the hvac system should first be wired through a pressure or flow switch, so that the refrigerant path only switches to the FPH heat exchanger when there is true water flow. Back when I implemented, FPH ignored flow which leaves you vulnerable to AC failure (compressor overheat/overpressure) if the pump fails to start, which in my experience VSP’s are prone to do. But all pumps fail at some point, so logic is needed to keep the hvac from switching to FPH if flow is not happening. They also sell inexpensive delay modules that might also be a good addition to that flow path, so that the pump has time to prime and fully create flow before switching the refrigerant path.

It's not rocket science but it is nontrivial, best handled by an electrician and/or pool pump person with similar knowledge or experience, at least for the pool/pump interfaces. More difficult is the installation of the sporlan refrigerant valve and check valve(s) that are brazed in place to reroute refrigerant. That requires an epa608 certified hvac tech to remove/recover current refrigerant, install the sporlan valve and, as necessary refrigerant check valve(s), then re-charge refrigerant and test all functionality. For some of us, finding an HVAC tech willing to do that work can be the toughest part (think of a tech familiar with “heat recovery” systems). When found, that tech will want to work hourly and they likely will need to speak with FPH experts about check valve dependencies and such, depending on your hvac design. Back when I did it, I learned enough to be the go-between interface between FPH techs and local HVAC tech – and I had a very good hvac tech. Somewhere in all those posts I included what it cost me for all that, including tech labor.

I think most of us got all that worked out before buying the FPH, but I applaud your gumption if you just dove in!

I have a pressure switch calibrated for my flow rate that will break the 24vac to the recovery valve and fan relay in the event the flow is not high enough.

I also had to wire in a relay to disconnect power to the hotspot because my heat pump has constant 24vac when the system is in AC mode. The control panel will remain powered on after the call for cooling is complete. I guess the 24vac from the sense wire for the reversing valve back feeds the controller. Hotspot sent me a new control panel after going round and round with them on this which still does the same thing. I put in a relay that breaks that connection. Problem solved but it kinda ****** me off that they were unaware of this and had no fix.

Straight ac wont have this issue though.

 

[nuttyp]

I also had to wire in a relay to disconnect power to the hotspot because my heat pump has constant 24vac when the system is in AC mode. The control panel will remain powered on after the call for cooling is complete. I guess the 24vac from the sense wire for the reversing valve back feeds the controller.

That seems so weird. I guess it seemed weird to you too. I don't know the heat pump control wiring intimately, but it seems like there must be 24vac some place in the heat pump that is only active during a home a/c cooling cycle. It also makes me wonder if somehow the internal FPH controller wiring has a mistake. But I'm also guessing you went through all that with great care. Of course your solution is cool, just that one would hope that extra relay would not be necessary, therefore not necessary to ever power off the FPH controller.

I don't know if this clarifies, but if my memory is correct, on my install the FPH controller was indeed always on, just that it would not send it's 24vac back to the a/c system (for the reversing valve and fan relay) unless conditions called for pool heat while home a/c is cooling. Of course, under that condition of pool heating, the FPH also closed the relay for the pump, which initially I had just wired in parallel with a mechanical time clock. As noted, when I went with VSP that changed. I don't know if that helps, as you've no doubt been through all that logic many times!

 

[nuttyp]

Also wondering if you might have run a 4 conductor low voltage cable between the two controllers, such that perhaps the FPH is "thinking" that the a/c is cooling by way of picking up induced current in the 2nd pair of wires. Or the "commons" of those two 24vac circuits interfering with one another. Easy enough to test by temporarily running a dedicated cable from the heat pump back to fph with the former pair disconnected. Just an idea.

 

[JamesW]

Intelliflo Pump Needs Two Brains

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www.troublefreepool.com

FPH - Hotspot Energy Install Begins!

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www.troublefreepool.com

 

[JamesW]

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[JamesW]

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www.troublefreepool.com

Hotspot FPH, very similiar use case as Drglanton

I have an almost same use scenario but am puzzled why this can't be made to work if we have the proper solenoid actuation from within Intellicenter programming. Given scenario: Intellicenter shared equipment load center (at least the i5, I can switch it to the i8 if needed for sufficient...

www.troublefreepool.com

 

[Maverick23]

That seems so weird. I guess it seemed weird to you too. I don't know the heat pump control wiring intimately, but it seems like there must be 24vac some place in the heat pump that is only active during a home a/c cooling cycle. It also makes me wonder if somehow the internal FPH controller wiring has a mistake. But I'm also guessing you went through all that with great care. Of course your solution is cool, just that one would hope that extra relay would not be necessary, therefore not necessary to ever power off the FPH controller.

I don't know if this clarifies, but if my memory is correct, on my install the FPH controller was indeed always on, just that it would not send it's 24vac back to the a/c system (for the reversing valve and fan relay) unless conditions called for pool heat while home a/c is cooling. Of course, under that condition of pool heating, the FPH also closed the relay for the pump, which initially I had just wired in parallel with a mechanical time clock. As noted, when I went with VSP that changed. I don't know if that helps, as you've no doubt been through all that logic many times!

That seems so weird. I guess it seemed weird to you too. I don't know the heat pump control wiring intimately, but it seems like there must be 24vac some place in the heat pump that is only active during a home a/c cooling cycle. It also makes me wonder if somehow the internal FPH controller wiring has a mistake. But I'm also guessing you went through all that with great care. Of course your solution is cool, just that one would hope that extra relay would not be necessary, therefore not necessary to ever power off the FPH controller.

I don't know if this clarifies, but if my memory is correct, on my install the FPH controller was indeed always on, just that it would not send it's 24vac back to the a/c system (for the reversing valve and fan relay) unless conditions called for pool heat while home a/c is cooling. Of course, under that condition of pool heating, the FPH also closed the relay for the pump, which initially I had just wired in parallel with a mechanical time clock. As noted, when I went with VSP that changed. I don't know if that helps, as you've no doubt been through all that logic many times!

It is very strange. The heat pump version of the controller uses the 24v output to the reversing valve to check what mode the system is in. In my system where the reversing valve solenoid is active during cooling it will stay active even after the system switches off. There must be some kind of flaw where in the 2 ac-dc converters in the unit can back feed each other allowing the controller to stay energized. The crux of this is that the unit only performs certain checks on start up if it never turns off the system could choose to keep the pool heater active during a heat call which puts the system into a very dangerous state where the reversing valve switches and the racetrack is still active from the FPH controller effectively causing the compressor to pump down into a vacuum state. Ask me how I figured this out…

Hotspot claimed a diode was in the system to prevent back feeding which makes sense but somehow the controller was still getting power from the reversing valve signal. I told them to look at integrating a transistor with a pull down resistor. They said they would look into it but never heard back.

 

[Maverick23]

Also wondering if you might have run a 4 conductor low voltage cable between the two controllers, such that perhaps the FPH is "thinking" that the a/c is cooling by way of picking up induced current in the 2nd pair of wires. Or the "commons" of those two 24vac circuits interfering with one another. Easy enough to test by temporarily running a dedicated cable from the heat pump back to fph with the former pair disconnected. Just an idea.

Ran 4 thhn wires in NM conduit. Technically the common is shared. HVAC controller decides if solenoid needs power or not based on thermostat heat or cooling call.

I spent hours troubleshooting at every stage of the system.

 

[nuttyp]

Dude that is wild and interesting, thanks for the explanations. And wow, that’s a lot. Awhile back I read through your plans for FPH on a heat pump system, I knew it would be complicated. But it’s perhaps enough to frighten away anyone thinking of implementing FPH to a home AC/heatpump. First, I didn’t realize FPH even had a different controller for driving heat pumps, now I start to understand why.

More thoughts, if you’re interested in continuing…… If not I’ll understand.

“In my system where the reversing valve solenoid is active during cooling it will stay active even after the system switches off”. Do you mean that is the heat pump design such that it leaves that valve energized even when the system is off/idle? I could see a motivation for that to prevent unnecessary moving of refrigerant around, but If so that still seems like an odd design to leave a coil (for a relay or valve or whatever) energized all the time even when the entire system is idle. Still, being all grumpy about your heat pump’s design doesn’t help you much!

Anyway, for such a system (active valve coil when idle) it seems to indicate a need for FPH to find a better way of sensing the mode of the heat pump. Duh, right? Maybe some other signal from the thermostat – cool vs heat mode perhaps - driving a small relay (eg opto isolating chip) to interrupt the sensing wire back to the right place in FPH. Unless I’m misunderstanding, my logic (and my head hurts) tells me that if FPH needs to sense that reversing valve signal, how could they interrupt that same sensing with anything – let alone a simple device like a diode. Even if their FPH logic is sound, meaning the diode is in the right place to prevent back feeding, the diode will only suppress one half the current (the negative-going cycle or positive, whichever based on polarity of insertion). So some current would flow regardless, and who knows if that current is sufficient to cut off the device it’s driving. Hence your idea of something better to cutoff all current, whether a transistor or something else. But either way, it seems like a tail chasing scenario wherein “I need that signal to know the mode, but I also need to ignore it – “sometimes”. Ugh. If I sound confused, I probably am! Perhaps one part of the FPH always needs to sense it, and another FPH input needs to ignore it. Again, circular logic, and more weirdness.

“which puts the system into a very dangerous state where the reversing valve switches and the racetrack is still active from the FPH controller effectively causing the compressor to pump down into a vacuum state. Ask me how I figured this out” Well, I’m asking, but I have 3 guesses. If the low side was in vacuum then the high side should be very high. Dangerous indeed! If you didn’t have gauges on there when it first happened, I’m guessing the compressor cut-out – either due to high pressure, or low pressure on that side, or it cut-out from overcurrent/overheating. Then gauges would have confirmed the action. Nothing that you want your compressor experiencing, of course. Third guess is that something popped and you lost all refrigerant, yuk that.

Hopefully FPH gets back to you with a better solution. Maybe not hold our breath, right? I watched their site for diagram changes for awhile after I advised them back in 2012-ish they specified the wrong rib relay for the cooling fan cutoff (NC vs NO) but never saw the change. Perhaps they fixed it or you caught it yourself.

“Technically the common is shared” I guess you mean that one side of the 24vac circuits are common to ground and therefore “shared”. Not sure that needs to be the case, but either side (FPH or heat pump) could ground one side, so shared in that sense, with possible stray currents. Might be interesting, if so, to find where and isolate the 24vac circuits from ground.

“and the racetrack is still active” Is racetrack a typo? Or I don’t know what that is, except that it’s a place to lose money

So.... How is it working out for extending your swim season with free heat? Free if you don't consider paying yourself for tons of hours troubleshooting!

 

[Maverick23]

Dude that is wild and interesting, thanks for the explanations. And wow, that’s a lot. Awhile back I read through your plans for FPH on a heat pump system, I knew it would be complicated. But it’s perhaps enough to frighten away anyone thinking of implementing FPH to a home AC/heatpump. First, I didn’t realize FPH even had a different controller for driving heat pumps, now I start to understand why.

More thoughts, if you’re interested in continuing…… If not I’ll understand.

“In my system where the reversing valve solenoid is active during cooling it will stay active even after the system switches off”. Do you mean that is the heat pump design such that it leaves that valve energized even when the system is off/idle? I could see a motivation for that to prevent unnecessary moving of refrigerant around, but If so that still seems like an odd design to leave a coil (for a relay or valve or whatever) energized all the time even when the entire system is idle. Still, being all grumpy about your heat pump’s design doesn’t help you much!

Anyway, for such a system (active valve coil when idle) it seems to indicate a need for FPH to find a better way of sensing the mode of the heat pump. Duh, right? Maybe some other signal from the thermostat – cool vs heat mode perhaps - driving a small relay (eg opto isolating chip) to interrupt the sensing wire back to the right place in FPH. Unless I’m misunderstanding, my logic (and my head hurts) tells me that if FPH needs to sense that reversing valve signal, how could they interrupt that same sensing with anything – let alone a simple device like a diode. Even if their FPH logic is sound, meaning the diode is in the right place to prevent back feeding, the diode will only suppress one half the current (the negative-going cycle or positive, whichever based on polarity of insertion). So some current would flow regardless, and who knows if that current is sufficient to cut off the device it’s driving. Hence your idea of something better to cutoff all current, whether a transistor or something else. But either way, it seems like a tail chasing scenario wherein “I need that signal to know the mode, but I also need to ignore it – “sometimes”. Ugh. If I sound confused, I probably am! Perhaps one part of the FPH always needs to sense it, and another FPH input needs to ignore it. Again, circular logic, and more weirdness.

“which puts the system into a very dangerous state where the reversing valve switches and the racetrack is still active from the FPH controller effectively causing the compressor to pump down into a vacuum state. Ask me how I figured this out” Well, I’m asking, but I have 3 guesses. If the low side was in vacuum then the high side should be very high. Dangerous indeed! If you didn’t have gauges on there when it first happened, I’m guessing the compressor cut-out – either due to high pressure, or low pressure on that side, or it cut-out from overcurrent/overheating. Then gauges would have confirmed the action. Nothing that you want your compressor experiencing, of course. Third guess is that something popped and you lost all refrigerant, yuk that.

Hopefully FPH gets back to you with a better solution. Maybe not hold our breath, right? I watched their site for diagram changes for awhile after I advised them back in 2012-ish they specified the wrong rib relay for the cooling fan cutoff (NC vs NO) but never saw the change. Perhaps they fixed it or you caught it yourself.

“Technically the common is shared” I guess you mean that one side of the 24vac circuits are common to ground and therefore “shared”. Not sure that needs to be the case, but either side (FPH or heat pump) could ground one side, so shared in that sense, with possible stray currents. Might be interesting, if so, to find where and isolate the 24vac circuits from ground.

“and the racetrack is still active” Is racetrack a typo? Or I don’t know what that is, except that it’s a place to lose money

So.... How is it working out for extending your swim season with free heat? Free if you don't consider paying yourself for tons of hours troubleshooting!

I actually suggested an NPN transistor or an octocoupler design to sense the reversing valve. I’m on the same page as you with that one. Signal needs to be monitored but isolated to prevent back feeding.

Carrier probably designed the HP this way to eliminate the cycling of the reversing valve. Not sure why it needs to be energized all the time. Hotspot has a setting in the controller to indicate which style you have (energize on cool or energize on heat).

Regarding the pump down on the system I wasn’t aware of the failure mode when it happened. I was testing the heat mode on the thermostat and heard the HP acting very strange.

The weakness is in the racetrack design. The racetrack is two one way check valves and two solenoids. Looks like a race track thus the name. When activated for pool heating it prevents refrigerant from flowing the wrong way.

It was active and the HP heat mode was active so the compressor was basically pulling on vacuum because the system had isolated itself. A bit hard to explain without the diagram in front of you. Works till it doesn’t kinda thing.

Shared in that there is a Y and a G wire that makes up the 24VAC to turn on the HP. The heat pump reverse valve signal (usually O) is also 24VAC and shares the same ground.

So the hotspot control panel uses all three of these wires to power the two AC/DC converters that converts the signal for the arduino controller to use. One is to power the arduino and the other is a voltage sense pin that is programmed. Problem is this sense pin is not isolated or disconnected on shutoff so it will continue to power the arduino. I wired a mechanical relay to break the connection when the Y signal drops at the thermostat. This was also hotspots suggestion which I think is a really garbage way to manage this flaw.


Heater works great, it does in fact heat the pool. However when the pool temp nears 85 and up I don’t think it really saves energy. The compressor is essentially using hot water to condition the air which raises the refrigerant pressure and thus the watts consumed by the compressor. You are basically getting free heat though.

It’s a science project and a half. Not for the faint of heart and be prepared to learn HVAC or have a friend who is a tech because they will prob be pulling their hair out next to you.

 

[nuttyp]

Thanks @Maverick23 for all the additional explanation, sorry for slow reply......

Carrier probably designed the HP this way to eliminate the cycling of the reversing valve

Thinking same

The weakness is in the racetrack design. The racetrack is two one way check valves and two solenoids. Looks like a race track thus the name. When activated for pool heating it prevents refrigerant from flowing the wrong way

I get it, thanks. While pursuing my epa608 cert I wound up with a couple racetrack diagrams pinned to my wall - still there! In those travels I just never ran across the racetrack term, it's a perfect description. Just more track options, controls and valves for the heat pump versions.

So the hotspot control panel uses all three of these wires to power the two AC/DC converters that converts the signal for the arduino controller to use. One is to power the arduino and the other is a voltage sense pin that is programmed. Problem is this sense pin is not isolated or disconnected on shutoff so it will continue to power the arduino. I wired a mechanical relay to break the connection when the Y signal drops at the thermostat. This was also hotspots suggestion which I think is a really garbage way to manage this flaw.

For starters I didn't even realize that FPH now uses an arduino these days, at least for heat pump versions. I've been answering questions about how it works, but my install, circa 2012, was vanilla and dated, so I need to season my replies given the updates! I'd be tempted to consider reprogramming the arduino in some way, or else adding some other logic - maybe via a simple programmable logic array PLA device - but you have the better grasp of all the logic!

Heater works great, it does in fact heat the pool. However when the pool temp nears 85 and up I don’t think it really saves energy. The compressor is essentially using hot water to condition the air which raises the refrigerant pressure and thus the watts consumed by the compressor. You are basically getting free heat though

That makes sense, and it's possible that the compressor current/load savings I reported were measured with cooler water, I'd have to re-check my data. I guess you still save a couple amps because the condenser cooling fan isn't running.

Another, perhaps remote possibility, is refrigerant overcharge that would raise the pressures and increase load. Not that you want to think about that But it was always a mystery to me that FPH sized things without really addressing more detailed refrigerant volumes and whether they are equal when running in each mode. Back in the day FPH just recommended heat exchanger sizing based on A/C tonnage, but I always wondered if the system might be over or under charged in one mode or the other, even if only slightly, if the FPH exchanger used more or less volume than the existing condenser coils. I suppose careful measurements of subcooling and/or superheat values - compared to specified nameplate values on the heat pump - would verify that.

All of that assumes you have any interest in continuing the giant science project. Then it's like you work for FPH

Overall, am very glad it's working for you!