Inground gas heater on above ground pool

[BillyMack]

Can I use an inground heater on an above ground pool? I was told the output would be too hot and melt the hoses and fittings. Maybe that defends on the flow rate. I was also told by someone else that a 100k btu heater would be to small.

What is the best way to get the rights size considering pool size, pump size, flow rate, etc? I have too much shade for solar and am afraid and 50K btu heat pump would be too expensive and not supply enough heat. So I'm leaning toward natural gas.

I have a 15x24 AGP with 3/4hp pump and sand filter.

 

[jblizzle]

Welcome to TFP!!!

I would think that you could use any heater you want. Usually they only raise the water temp by a few degrees at a time so the melting of hoses and pools sounds silly to me. Of course heating works best at high flow rates. IF the flow was too slow, most heaters would turn off to avoid overheating the exit water and/or damaging itself.

Generally the size of the heater just determines how fast the pool is heated, while still using a similar amount of gas.

What is the volume of your pool? How much do you want to raise the temperature and how fast do you want to do it?

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Assuming 10k gallons, to raise the pool by 10 degrees would require ~830,000 BTUs. So a 100k BTU heater running at 83% efficiency (a reasonable number) would take about 10 hours to raise the pool by 10 degrees (not counting losses to evaporation and radiant losses).

 

[BillyMack]

My pool is about 9000 gal. I'd like to raise the temp 10-15 deg and more concerned about efficiency/cost than speed.

 

[jblizzle]

All gas heaters will require about the same amount of gas to heat a pool ... their efficiencies are about the same. But the slower you are heating it, the more time for losses to the environment.

9k *8.3 lb/gallon * 10 degrees = 747000 BTUs

100K heater should do 10 degrees in 9 hours so 15 degrees in 13.5 hours
400k heater should do 10 degrees in 2.25 hours so 15 degrees in 3.4 hours

If you are going to maintain a higher temp and only in the summer, then the heat pump might be more efficient. But, it will not work well when the air is under 60 degrees and it will be a lot slower than a gas heater.

 

[BillyMack]

Thanks, that all makes sense. Should I be concerned about the flow rate from my pump, especially if I go with a bigger heater?

 

[jblizzle]

I am not sure if the required flow rate for the heater changes with size or not. I would think that any reasonable single speed pump (or 2-speed on high) should provide enough flow rate for the heater to run. But, I am not positive on this.

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It is not going to be cheap to keep adding 10+ degrees to your pool though.

 

[BillyMack]

Thanks, you are very helpful. I'll just have to see how the cost works out and if it's too high I'll have to lower my expectations.

 

[Patrick_B]

They make these types of heaters for small ABG pools too. Gas or propane as I recall.