DHW Coil or Indirect Water Tank?

hotblast1357 · Post by **hotblast1357** » Sat. May. 16, 2015 5:57 pm

My New Yorker boiler already has a DHW coil, and I have a two year old electric water tank, is it better too purchase a bronze circulator and use the coil and electric tank, or purchase a indirect tank and add another zone too my system, by next summer I will hopefully be heating a hot tub also, I already have a water to water exchanger for it, I plan to run the yorker 365 24/7.

Post by **StokerDon** » Sat. May. 16, 2015 10:58 pm

If you can manage the extra plumbing, I see no reason not to use both, I do. I think a hot tub will suck out a lot of heat, in that case it is nice to have the heat storage of an indirect.

I'm spoiled, I like having options, that's why I use both.

-Don

hotblast1357 · Post by **hotblast1357** » Sat. May. 16, 2015 11:01 pm

The heat storage of an indirect only applies to my DHW though correct? The hot tub will be heated with a zone and water too water plate exchanger.

Post by **StokerDon** » Sat. May. 16, 2015 11:42 pm

Oh, OK.

You have a coil in the Yorker. you can use the water heater as a tempering tank and run it through the coil to heat it up 120 degrees.

I still like having the coil and the indirect. The indirect can use heated water from any source. You can hook a solar collector to it and have the sun heat your DHW if you wish.

-Don

hotblast1357 · Post by **hotblast1357** » Sat. May. 16, 2015 11:50 pm

Well my plan was too heat my DHW and hot tub all summer with the yorker, I just wanted to know what the best way was too heat my DHW, if I use the yorker's coil I won't be using the boiler water, it will be sitting still, if I use a indirect tank or a side arm heater I will be circulating the boiler water but does that matter?

McGiever · Post by **McGiever** » Sun. May. 17, 2015 8:10 am

Does it matter?

Boiler water is not generally added to or replaced since it is a closed loop...water through the inside of a coil is continuously replaced or added to since it it ends up going down the drain as it is used.
New water always being added can bring along a never ending supply of minerals such as iron, calcium and other salts that can build up on the inside the coil tube walls over time and hinder the effective flow amount going through the ever narrowing 1/2" diameter coil tubing.

hotblast1357 · Post by **hotblast1357** » Sun. May. 17, 2015 9:03 am

Ok so the a sidearm heat exchanger is out of the question also then as it will clog eventually too, so my best bet is a indirect tank?

McGiever · Post by **McGiever** » Sun. May. 17, 2015 9:15 am

hotblast1357 wrote:Ok so the a sidearm heat exchanger is out of the question also then as it will clog eventually too, so my best bet is a indirect tank?

Best???
Yes, but is also the most costly.
Some homes have much or little minerals in their domestic water supply.

Got my Amtrol 41 gallon Boiler Mate from a Craig's List ad, and for less than 1/3 of a full price new one.

Note: Recovery rate of an indirect is so fast that the size does not match as same size as for a equivalent gas or electric unit. Rapid recovery makes indirect only need to be approx. 1/2 size.

Post by **StokerDon** » Sun. May. 17, 2015 10:04 am

Another advantage of the idirect is it only heats the domestic water to the set point, usualy 120 degrees. With the coil, the cold water is coming in and being heated to the boiler temp. Then coming out of the coil into a mixing valve adding cold water to it to get the temp down to 120 degrees. I think because of this you may use a little less coal with the indirect.

If you use both, you can do things like, plumb the coil to your washing machine and dish washer with no mixing valve. Run the indirect to the sinks, showers and tubs. This way you have very hot water to clean the things your not touching and normal hot water for the things you are touching.

Thats a bit more complicated but a good option for later when you get board.

-Don

hotblast1357 · Post by **hotblast1357** » Sun. May. 17, 2015 10:08 am

Yes I think I'll leave the coil in it, and just use it for something down the road. I'm sure I will come across a indirect tank at some point, I've been watching for one. I'm not too pressed too get the DHW hooked up until I can get the hot tub hooked up, because if I do not have the hot tub hooked up, it probably won't be worth it too run all summer for just my domestic water. It all also depends on how good this things sips coal and idles.

Post by **StokerDon** » Sun. May. 17, 2015 10:52 am

A quick search of Plattsburg turned up some interesting results;

40 gallon stainless indirect $800.
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40 gallon indirect $200.
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FREE home heating system. in there is a 41 gallon Boiler Mate. The catch is, you have to remove the oil tank, boiler and boiler mate. Looks like you get all the controls and pumps with it to.
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50 gallon and 40 gallon indirect, $200 each, $350 for both.
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Tripple aquastats $25.
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You have more interesting stuff for sale up there than I do down here!

-Don

EDIT; I saw your Hot Blast for sale to.

Post by **Lightning** » Sun. May. 17, 2015 11:43 am

Just a note..

The hot tub won't take as much heat as you might think. I kept mine warm (about 90 degrees - 400 gallons) thru the whole winter with just a small coil in the fire box while it wasn't being used. Then, just turned on the tub's electric element when I wanted to bring it up to the 102 degrees that is comfortable hot tub temp, when I wanted to use it. According to what I've read, (of course it depends on usage) a tub will add $50-60 to the electric bill. A quarter of that is hot tub pumps, so figure $40-50 for heating. Figure 400 KW per month for heating.

1 kW = 3412.142 BTU X 400 KW = 1364800 = 136.48 pounds of coal per month
(I used 10,000 BTU per pound to factor efficiency.)

Which works out to $15-16 worth of coal (at $235/ton) per month

NICE..

hotblast1357 · Post by **hotblast1357** » Sun. May. 17, 2015 4:51 pm

It will still be cheaper than electric heat, and maybe I'll keep it at 105 constantly, I know it's not a big load but it's still a load, and if this boiler idles good and sips coal I won't have to worry about it, it depends on how much it saves over electric hot water.

McGiever · Post by **McGiever** » Sun. May. 17, 2015 6:08 pm

hotblast1357 wrote:It will still be cheaper than electric heat, and maybe I'll keep it at 105 constantly, I know it's not a big load but it's still a load, and if this boiler idles good and sips coal I won't have to worry about it, it depends on how much it saves over electric hot water.

For sipping coal a stoker will beat a shovel every time.
Hand fed boilers have a hard time staying lit under light loads with 12-24 hour tending cycles.
Stokers get revived hourly for some seconds with a repeated timer cycle of the fan and some coal feed.

hotblast1357 · Post by **hotblast1357** » Sun. May. 17, 2015 6:52 pm

I understand completely mcgiever, and I know boilers and furnaces are different animals, but coal is coal, and in that crappy hotblast furnace I could burn 24-36 hours on idle with a 160 degree fire burning 18-19 lbs per 24 hours. I agree a stoked is the best way to go, but I gotta try the hand fed first, I like tinkering and tending.