# Tankless Water Heater as Pool Heater



## pjdenterprises (Jan 20, 2014)

I have an NG fired tankless water heater in the back left corner of my cabana which is used to heat up a bar sink, bathroom sink and bathroom shower. 

I am installing a pool this week that is literally 7’ off of the back left corner of my cabana. 

How could I integrate this tankless heater to heat my pool system ? Has anybody done this before. Again it is not a tankless Boiler it is a tankless hot water heater. Is there anyway to install an aqua stat to this? Can I loop it from the return from the pool?

Please advise. Thank you. 


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## justinramani (Dec 26, 2014)

How would that work? Pool pumps recycle pool water. Your tankless would be feeding fresh water into your pool causing it to overflow. You also don't want to circulate pool water though your tankless.

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## Golden view (Feb 16, 2012)

It could be done with a plate heat exchanger set up and two pumps.


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## jhark123 (Aug 26, 2008)

You could do it (who knows how long it would last), but you would have to remove potable water from the system.


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## pjdenterprises (Jan 20, 2014)

@goldenview

Plate heat exchanger and two pumps. Please explain. 

I understand the issue of running pool water through tankless heater is no good, however I have heard this setup is possible. 

I just don’t know where to start. Any ideas on how to do this with some sort of bypass and relay would be appreciated. 


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## Golden view (Feb 16, 2012)

One pump to push pool water through the plate heat exchanger. One to push potable water through the exchanger and water heater. The plate heat exchanger keeps the water from crossing over.


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## Seven-Delta-FortyOne (Mar 5, 2011)

Pretty easy to set up. Don't know if it would heat the pool, as I don't know what size pool, and what size tankless heater you have.

Pumping potable water into the pool and overflowing it is not an issue. :blink:

You set it up just like a re-circ system in a house, minus the inlet. Thermostatically controlled pump. :thumbsup:

Keep in mind, many, if not most older tankless units do not recommend doing a re-circ system. Some would even void the warranty if you did. 

My understanding is that the units couldn't handle high inlet water temperatures.

I also have know idea how pool chemicals, especially chlorine, would react with the internal components of a tankless unit, but it's something to keep in mind.


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## nesc39 (Nov 20, 2014)

Your cabana tankless is not even close to btu to heat your pool. If you wanna try it then just plumb a tee into off your pool filter to go through the tankless in back into the pool. Don’t ask me if chlorine will destroy your heat exchanger


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## Golden view (Feb 16, 2012)

nesc39 said:


> Your cabana tankless is not even close to btu to heat your pool. If you wanna try it then just plumb a tee into off your pool filter to go through the tankless in back into the pool. Don’t ask me if chlorine will destroy your heat exchanger


Most tankless water heaters I install are 199,000 BTU/hour. Similar to many pool heaters.


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## Ale_Brewer (Nov 18, 2019)

The heat exchanger that is inside your tankless water heater is meant to work with softened water. The level of hardness in your pool is way more than what's in domestic cold water. This would work with a simple recirc pump but the heat exchanger wouldn't last long.


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## Delta T (Jan 23, 2021)

Golden view said:


> Most tankless water heaters I install are 199,000 BTU/hour. Similar to many pool heaters.


Yes btu is similar but volume and furnace are of exchanger not same as a pool heater, it will work but not as well as a pool heater


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