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  1. #1
    Join Date
    Jul 2012
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    4

    Default Indirect water heater or Traditional

    My AO SMith gas fired HW heater 50 gallons is closing in on 10 years of age. I'm expecting that it will be going soon. I'm doing an AC upgrade and the company also does plumbing/heating and I have been recomended to install a 40 gallon Heat Flo Indirect Water heater. Coil in the boiler and a seperate zone/circulator to the tank. I live in the NY Long Island area -family of 4 and we do run out of hot water for showers. Cost is a bit pricey 2295 installed - would like some feedback on the price. Also for 200 dollars more I can go to the 50 gallon tank. The recovery(max first hour rating gal/hr) on the 40 at 140 degrees is 215 gallons, at 115 degrees it is 284 gallons. The recovery on the 50 for the same temps is 234 and 308. Don't have a jacuzzi - would guess the 40 is enough HW? Also is this the way to go - some old time plumbers like the traditional seperate units - HW and boiler - boiler won't need to run in the summer etc. The sales guy makes the point that in the winter you make the hot water along with your heat - so no cost. What do the professional think on these points above. Cost, Brand, Size and Switching over...thanks, John

  2. #2
    Join Date
    Jul 2010
    Location
    SoCal
    Posts
    6,493

    Default Re: Indirect water heater or Traditional

    There is a reason why old time plumbers recommend the traditional tank WH. It has proved itself as a work horse, providing hot water economically, while the alternative's costs are questionable.

    Go with a new 50 gal WH - about $750 installed.

  3. #3
    Join Date
    Feb 2010
    Location
    South*East
    Posts
    1,208

    Default Re: Indirect water heater or Traditional

    Quote Originally Posted by ptwash13 View Post
    My AO SMith gas fired HW heater 50 gallons is closing in on 10 years of age. I'm expecting that it will be going soon. I'm doing an AC upgrade and the company also does plumbing/heating and I have been recomended to install a 40 gallon Heat Flo Indirect Water heater. Coil in the boiler and a seperate zone/circulator to the tank. I live in the NY Long Island area -family of 4 and we do run out of hot water for showers. Cost is a bit pricey 2295 installed - would like some feedback on the price. Also for 200 dollars more I can go to the 50 gallon tank. The recovery(max first hour rating gal/hr) on the 40 at 140 degrees is 215 gallons, at 115 degrees it is 284 gallons. The recovery on the 50 for the same temps is 234 and 308. Don't have a jacuzzi - would guess the 40 is enough HW? Also is this the way to go - some old time plumbers like the traditional seperate units - HW and boiler - boiler won't need to run in the summer etc. The sales guy makes the point that in the winter you make the hot water along with your heat - so no cost. What do the professional think on these points above. Cost, Brand, Size and Switching over...thanks, John
    A Indirect Water heater is a great way to make hot water but as far as cost savings, that will depend on how efficient your boiler is. As far as it being free in the winter months. It takes BTU's to make hot water and there not free. The water in the boiler may be hot in the winter months but when it is run through the indirect heater to make hot water that will cool it down causing the boiler to fire and heat it back up. So there goes your free hot water.

    John

  4. #4
    Join Date
    Feb 2008
    Posts
    198

    Default Re: Indirect water heater or Traditional

    ptwash13:

    It sounds like you have a good grasp of the recovery rates of the indirect and the tank heater; what you have to do now is to consult the charts (see the 2nd site below to do these calculations) in the sites below to determine the PEAK HW USAGE that your family uses during the busiest time of the day----usually during the morning rush hour when everyone is getting ready for work/school, etc.

    You would have to determine if the recovery rate will meet the peak usage gallons for all the HW used during that period.

    You mentioned a "coil in your present boiler"----this sounds like you may have previously had a "tankless coil" for all your hot water needs, & then added a gas boiler when the DHW was insufficient---this is typical, often done, but usually leaves the original aquastat on the boiler (triple aquastat); a triple aquastat will fire anytime the boiler water temp drops below approx 130-140 degrees---you DO recover some of this heat when the indirect calls for heat from the boiler, but you DO also waste gas during the summer months when the boiler keeps firing for no reason to maintain the boiler water at 140 degreees----you might ask the salesman/installer if he could change the present triple aquastat on the boiler to one that causes the boiler to fire ONLY ON A CALL FOR HEAT (from the t-stats in the rooms, or from the indirect when IT calls for heat)---this will save you lots of gas in the warmer months---a small number of boilers that have a triple aquastat should not be changed; these include those that have closely-spaced pin-type nipple heat exchangers that have a history of clogging with soot during the heating season.


    I have always favored the indirects----they avoid using another gas burner to heat the HW, as well as a 2nd flue, which almost always means a drop in efficiency----one gas burner on the boiler is all you need to heat the water to heat the home, as well as the domestic hot water (DHW)----it's a combination that can't be beat----$2295 is a typical price for an indirect---providing it has a stainless steel tank inside of a tank, as opposed to just a coil inside to heat the water---it wouldn't hurt to get a few more estimates, especially for the name brand units listed below; indirects last for decades; especially if you have water that has few minerals, and there is no burner to degrade the unit over time---it's simply a heat exchanger that holds the DHW until needed.


    If by chance the peak usage you compute exceeds the recovery rate (unlikely) you can always go to a slightly higher capacity indirect----the salesman and the installers should be figuring all this stuff out for you so you know that they're putting in the right unit----I would also get a price for several of the more well-known quality units that have been on the market for years-----Triangle Tube Phase 3, HTP Superstor, Weil-McLain G0LD Plus, TFI Everhot, Lochinvar Squire----all these have a stainless steel tank inside and NOT simply a less efficient coil.


    http://www.aceee.org/consumerguide/waterheating.htm
    http://web.extension.uiuc.edu/disast.../waterhtr.html
    http://hotwaterheatersguide.blogspot.com/
    Last edited by Dobbs; 07-12-2012 at 03:04 PM.

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