Indirect water heater

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Old 01-03-11, 11:29 AM
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Indirect water heater

I currently have a summer/winter setup and the tankless coil has degraded efficiency over the years (especially evident in cold weather). I installed the oil fired, wet bottom, cast iron boiler about 25 years ago and am hesitant to try replacing the tankless coil. I understand how indirect water heaters work, but have thought about a possible twist. If I were to install a standard water heater (propane and electric are my options) and and set it up to operate in a traditional fashion, but route my tankless output to supply the water heater as a pre-heater, would I gain anything due to the elevated supply temp? Have you ever heard of someone trying this?
 
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Old 01-03-11, 11:56 AM
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Why are you trying to avoid the indirect water heater?
 
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Old 01-03-11, 12:14 PM
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I would think you would have faster recovery but would gain nothing initially

As drooplug said, though, there doesn't seem to be a reason for what you're proposing
 
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Old 01-03-11, 12:22 PM
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I'm not trying to avoid it, I was just curious whether or not the arrangement I described would be beneficial.
 
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Old 01-03-11, 12:26 PM
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As I think about it, piping the tankless outlet to the water heater inlet eliminates the need to break into the house heating loop, and create a new zone, as well as providing less chance of "running out of hot water" during high demand.
 
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Old 01-03-11, 12:43 PM
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I agree with the decreased chance of running out, that does seem to be the benefit to this arrangement
 
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Old 01-03-11, 12:53 PM
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Guys, thanks for your time and for entertaining the ramblings of a guy with too much time on his hands.
 
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Old 01-03-11, 03:02 PM
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Danno, google the term 'Aquabooster' ... there are a few companies that make tanks that hook up to the tankless coil and by means of a circulating pump heat the tank up... so you have 30, 40, 50 gallons of hot water at your disposal. Not that it's gonna be more efficient, but at least you have STORAGE.

Here's one:

http://thermalproductsinc.com/wp-con...all-Manual.pdf

It's not a real good solution though, and might cost durn near what an indirect would.

If you can snag a used electric (or gas even) water heater that still has some years on it for almost free... and can do the piping yourself, it might be worth looking into. In other words, if you can do it for say $200 total, it's probably worthwhile.
 
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Old 01-03-11, 03:07 PM
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An indirect tank is the most efficient way to go. That's assuming you covert your current boiler to a cold start. Adding another zone for the indirect isn't that big of a deal and setting it up as priority over your heating zones will ensure quick recovery. It certainly seems far simpliar than the alternative you are proposing. When it comes time to replace your existing boiler, you don't have to worry about changing your indirect, it will work just fine with the new system.
 
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Old 01-03-11, 03:47 PM
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Had an aquabooster type tank for several years. Good riddance.

Your proposed approach is not nearly as efficient as you might think. Mostly because not only are you keeping the boiler hot all the time for ever-decreasing hot water performance (because the coil is shot and getting worse), but also because you will be short-cycling a fuel-fired water heater to do the top-off. Electric would be a slightly different story, but the big inefficiency is keeping the poor-efficiency tankless set up at all.
 
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Old 01-04-11, 10:25 AM
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Many Thanks.

Thanks all for your input. I think I clearly should be moving toward an indirect hookup. I've had nightmares over the thought of replacing my coil, and financial angst over replacing what continues to be a reliable, good performing heater.

Have a Happy New Year!!
 
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Old 01-04-11, 10:54 AM
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Originally Posted by dannon6 View Post
I currently have a summer/winter setup and the tankless coil ...?
hi dannon -

This is a little off the point but thought it might be interesting. I have the summer/winter setup and thankless coil. When I bought my house I remember the realtor talking about the summer/winter setup like it was a real super feature. I think he actually meant it. I really believe he was sincere. So I guess to many people it sounds great (sounded good to me back then - but not now).

When you come to this forum you get excellent information and the straight scoop. I'm with you - mine is going to be changed in the not too distant future.
 
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