choosing a boiler or tank heater


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Old 10-06-06, 05:49 PM
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Question choosing a boiler or tank heater

Nearing completion of our new home we are laying PEX tubing under concrete floors. Now I have to decide on a boiler or tank style hot water source. We will have solar panels and an 80 gal. storage tank. The house heat calculates to 140,000 BTU loss @ -40F. Yes, it's very cold here. There will be 2 gas inserts for looks and supplimental heat totalling 55,000 BTU's. I have looked at Polaris & Bock tank heaters. And I have looked at the reasonably priced Takagi, as well as the Burnham and the Lockinvar Knight boilers with its computer interface.
My question is which would seem to be more DIY friendly to install-Tank style or boiler. And which would be a smarter buy in my situation.
 
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Old 10-06-06, 06:04 PM
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Neat. I just plugged in -40F as an ODT for my house. 87k BTU/hr. My fingers are cold just thinking about it.

Is the solar for the radiant floor or just DHW? In either case, 80 gal storage seems about an order of magnitude too small, depending on your sunny days, etc. And if your ODT is -40F, I'm guessing you have some seriously low-altitude winter sun (if any?).

For a load of 85k BTU (140 minus 55), you are probably looking at a boiler rather than a tank, but to be honest I know nothing about the tank stuff.

If this is integrated solar and boiler, then of the options offered I'd go with the Knight. The modulation will help on fuel use, as will the condensing, which with radiant you should be there all the time.

The Knight controls could also be used to regulate the supply water temp to the radiant floor, again based on outdoor temp. With a tank, I'm guessing you'd have to buy some third party controls.

I've never done a DIY boiler install, but the Knight install manual seems pretty straightforward.
 
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Old 10-06-06, 06:30 PM
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Smile Boiler or Tank heater

It is a work in progress, the Solar is for DHW as the installer has designed it. I agree with the smallness of the 80 gal storage. I'll probably bump it to 120. We have lots of sunshine on those -40 days at 7200' altitude and are at 41 degrees north Lat.

I was really impressed with the Lokinvar Knight overview with its computer interface. I have worked with complex programs and am not intimidated by the Lokinvar system, in fact it gets me jazzed. The Distributer speaks highly of the Knight when I asked him to pick a favorite brand of several top brands he sells.

Since it is very difficult to find a plumber in our area who isn't book several months out I have to act now to finish the interior of our house and get moved in. So it's turning into a DIY not by choice but necessity.
 
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Old 10-06-06, 06:49 PM
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I'm also at 41N. But 7175 ft lower and probably 2000 miles east.

120 gal might get you there.

Everything I've heard and read about the Knight says it's a good one. Have at it.

Going to GSA this month?
 
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Old 10-06-06, 06:59 PM
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Smile

Thanks for the support.

Dallas in November? ah the tropics. Would be fun but house building calls.
 
 

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