Pool Heating with on demand water heater?


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Old 02-09-08, 08:41 PM
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Pool Heating with on demand water heater?

I live in the mid Atlantic, and would like to extend my enjoyable swimming season with a partially shaded pool. A friend just gave me an "on demand water heater" (for your house), and i was hoping to hook it up to my 30,000 gal pool. Any thoughts recomendations....other than the obvious "you're an idiot" comments?

Thanks,
 
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Old 02-10-08, 09:40 AM
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Try to post in the plumbing boiler steam, hot water systems forum. Someone there will probably know more about the heat on demand. I don't know any of the specs on it so can't be of any help other than it will probably cost big bucks to heat the pool.

I went ahaed and moved for you...

Can you guys here help with this question???
 
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Old 02-10-08, 10:47 AM
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Wink

Id say forget it. Even with the pool pump on 24/7. It will take 4 or 5 weeks just to pick up the pool temp 2o or 5o. You might look into a heatpump there on the pool. But then the cost of electric is just like that with gas high. . For what you want Id look into solar . I have put solar on 3 pools I have had and works great. (In FL.) Dont cost anything to run .(after you pay for it)
 
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Old 02-10-08, 02:42 PM
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You would not be able to get the proper flow of through any type of domestic water heater (or commercial that I can think of) to properly heat up the pool. Pool heaters generally have 2 inch connections where hot water heaters only have a 3/4 inch water connection.

Even if you adapted the 2 inch water lines to 3/4 inch, it would put a terrible strain on the pool pump likely causing it to burn out prematurely.
 
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Old 02-10-08, 03:23 PM
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Great info guys, thank you.. tmilan I hope this helps, not wanted you wanted to hear I'm sure. If you want to discuss other options please post back in the pool&spa forum...
 
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Old 02-10-08, 05:39 PM
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Lets put some hypothetical numbers on this: A typical tankless heater has a flowrate vs temp rise curve. Lets say yours will deliver 10 gallons per minute at a modest 30 rise ( raising temperature from 50 to 80, for example). 30,000 gallon pool, that would take 3000 minutes, or 50 hours. I cant estimate after that initial heatup what your heat losses and ongoing requirements would be. But for 2 days you are running a huge gas burner 24/7. The cost for gas would be large.

Your tankless heater probably consumes about 2 therms per hour. Here, we pay about $1.50 per therm, so that woud be $3 per hour, about $150 the first two days, maybe something less ongoing.
 

Last edited by 594tough; 02-10-08 at 05:44 PM. Reason: add
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Old 02-10-08, 05:45 PM
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Whats the BTU output of the heater?

If you run a 50k BTU heater for 48 hours straight, it wont use any more gas than running a 400k BTU heater for 6 hours.

you will however eat up more electricity running the pump for 48 hours straight. And then you also have to figure heat loss and keeping up with that. Should be easy to plumb into the existing plumbing. Just T it into the existing pipes and put an adjustable bypass valve on to control the flow through it
 
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Old 02-11-08, 02:02 PM
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On demand heater for Pool

Thank you gentlemen, for the information. Dr. Spa hit on the basic idea that I had. I will get the info for the specific unit that I have, and write back. Thank you for helping me with this thought process.
 
 

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