Best way to do DHW

Best way to do DHW

PostBy: NJJoe On: Tue Nov 05, 2013 11:56 am

Im thinking about getting a coal stoker for heating my home. An EFM or AHS is probably what I am going to choose but in my planning I have neglected to consider hot water. Through my reading here, I have seen several ways to produce DHW and would appreciate if someone could comment on the preferred method.

Option 1. Use the boiler's DHW internal coil. As I understand either boiler comes with a coil that is immersed inside the water jacket and I can run my hot water from this outlet to all my faucets.

Option 2. Use the boiler DHW coil and plumb the output to the input of a water heater. The coil could preheat the water entering the water heater and possibly lead to less water heater energy usage.

Option 3. Plumb a separate zone from boilet output dedicated to DHW and pipe that to an indirect fired water heater, heated solely from the boiler.

Option 4. Plumb in an ergomax heat exchanger. After reading about them I see that they function like an indirect fired water heater but essentially in reverse. I have no experience with these and it seems like a better design on paper.

Expected DHW usage is for 2 people at the moment doing regular laundry loads, showers/baths, dishwashing and cleaning. Would like to build reserve capacity into this system for possibly more people.

Nothing is built, this is still in planning phase. Any opinions would be appreciated. Thanks...
NJJoe
 

Re: Best way to do DHW

PostBy: McGiever On: Tue Nov 05, 2013 12:21 pm

WOW great question...betch-ya answers will be all over the place. :D
McGiever
 
Stoker Coal Boiler: AXEMAN-ANDERSON 130 "1959"
Hot Air Coal Stoker Stove: HARMAN MAGNUM
Hand Fed Coal Stove: RADIANT HOME AIR BLAST
Baseburners & Antiques: OUR GLENWOOD 111 BASEBURNER "1908"
Coal Size/Type: PEA / ANTHRACITE, NUT-STOVE / ANTHRACITE
Other Heating: Ground Source Heat Pump
Stove/Furnace Make: Hydro Heat /Mega Tek

Re: Best way to do DHW

PostBy: Sting On: Tue Nov 05, 2013 12:33 pm

option 2 or 3

It depends :D
Sting
 
Other Heating: OBSO Lennox Pulse "Air Scorcher" burning NG

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Re: Best way to do DHW

PostBy: titleist1 On: Tue Nov 05, 2013 12:45 pm

Do you plan to run the coal boiler through the summer for your HW?
titleist1
 
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite

Re: Best way to do DHW

PostBy: NJJoe On: Tue Nov 05, 2013 12:49 pm

McGiever wrote:WOW great question...betch-ya answers will be all over the place. :D



I know there will be alot of opinions on a topic that is commonly asked here but I did research and these 4 options are what I came across. I hope that by presenting my search results and consolidating them into one thread can get some people to comment on what they like and promote a good discussion. :cheers:
NJJoe
 

Re: Best way to do DHW

PostBy: NJJoe On: Tue Nov 05, 2013 12:55 pm

titleist1 wrote:Do you plan to run the coal boiler through the summer for your HW?


I'm not opposed to it. I see alot of members here run their coal boilers throughout the summer with modified settings for summer. If I use the boiler hot water coil exclusively, use an indirect fired water heater off a boiler zone or have an ergomax then I obviously would need to keep the boiler lit.

But if I run the hot water coil into a water heater, then I could turn off the boiler and use electricity during the summer for DHW. This I believe would eliminate the need to keep the boiler lit during summer, but what is the effect of cold water running through the DHW coil of a shut down boiler? Perhaps I would have to build in a loop to bypass the boiler and not have water running through it?
NJJoe
 

Re: Best way to do DHW

PostBy: franco b On: Tue Nov 05, 2013 1:00 pm

Cheapest to run and install is option 1. Will meet most needs with a 5 gallon per minute coil.
franco b
 
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

Re: Best way to do DHW

PostBy: Pacowy On: Tue Nov 05, 2013 1:09 pm

You are correct that you wouldn't want to run cold water through the coil if the boiler is shut off in the summer. Condensation is the enemy if you're not running the boiler.

My vote would be for option 1. We had it that way in our last house and had effectively infinite hot water for 2 adults and 6 kids including a bunch of teenagers. OK so it was an EFM 900, but it wasn't even working hard. IMO the boiler is better off to work and stay hot during the summer rather than try to stave off dampness and corrosion with coatings and light bulbs. The underfeed EFM stokers are generally very good at holding the fire during the intermittent demand pattern typical of summer DHW, and the AA/AHS guys will probably say the same.

Mike
Pacowy
 
Stoker Coal Boiler: H.B. Smith 350 Mills boiler/EFM 85R stoker
Coal Size/Type: Buckwheat/anthracite

Re: Best way to do DHW

PostBy: titleist1 On: Tue Nov 05, 2013 1:10 pm

NJJoe wrote:But if I run the hot water coil into a water heater, then I could turn off the boiler and use electricity during the summer for DHW. This I believe would eliminate the need to keep the boiler lit during summer, but what is the effect of cold water running through the DHW coil of a shut down boiler? Perhaps I would have to build in a loop to bypass the boiler and not have water running through it?


one reason i like the change of seasons because i get tired of doing the same chores. i get tired of cutting grass toward the end of summer while at the same time i look forward to starting up the coal stove, i get tired of raking leaves and am glad when they are all back in the woods, but look forward to moving the occasional snow we get, by the time spring rolls around i am ready to shut down the coal stove (blasphemy, i know) and not have to deal with loading it up and emptying the ash, but i look forward to cutting grass.

i said all that to justify my personal choice - option 2! :gee: (with the bypass you mentioned)
titleist1
 
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite

Re: Best way to do DHW

PostBy: whistlenut On: Tue Nov 05, 2013 1:14 pm

I prefer option 3, with an indirect on it's own zone. A tankless can cause a solid fuel appliance to overheat if there are the normal showers, cooking, cleanup, dishwasher.........then nothing for a load as the day warms up. Sure a dump zone could be added, but I prefer the indirect especially since you could have additional demands down the road. I really think folks underestimate the domestic hot water needs of a typical home. Today's tighter homes sure seem to be top heavy on the domestic demand, vs the heat load. Just one old man's opinion... :idea: I might add that I burn 24/7/365 so I like to avoid the summer condensation issues in equipment.
Last edited by whistlenut on Tue Nov 05, 2013 8:35 pm, edited 1 time in total.
whistlenut
 
Stoker Coal Boiler: AA130's,260's, AHS130&260's,EFM900,GJ&VanWert
Hand Fed Coal Boiler: Franks Boiler,Itasca415,NYer130,Van Wert
Hot Air Coal Stoker Furnace: Yellow Flame
Hot Air Coal Stoker Stove: Alaska-4,Keystoker-2,
Hand Fed Coal Stove: Alaska,Gibraltor,Keystone,Vc Vigilant 2
Hand Fed Coal Furnace: Van Wert, NYer's, Ford,Jensen.
Coal Size/Type: Rice,Buck,Pea,Nut&Stove
Other Heating: Oil HWBB

Re: Best way to do DHW

PostBy: fifthg On: Tue Nov 05, 2013 1:21 pm

option 1 Keeps it simple ,no question about it to me
fifthg
 
Stoker Coal Boiler: EFM 520
Hot Air Coal Stoker Furnace: Harman DVC 500
Hand Fed Coal Stove: warm morning
Baseburners & Antiques: Reading Foundry & Supply Co.
Coal Size/Type: rice,pea ,nut,stove Gale Mining Co Anthracite

Re: Best way to do DHW

PostBy: Sting On: Tue Nov 05, 2013 1:37 pm

option one as it is provides NO SCALD PROTECTION

Very dangerous
Image

option two is a poor mans indirect - but allows DHW production in the off season

option 3 - well also very good as long as you have an energy source to charge the tank

let me get back to you
Sting
 
Other Heating: OBSO Lennox Pulse "Air Scorcher" burning NG

Re: Best way to do DHW

PostBy: Townsend On: Tue Nov 05, 2013 1:38 pm

Pacowy wrote: The underfeed EFM stokers are generally very good at holding the fire during the intermittent demand pattern typical of summer DHW, and the AA/AHS guys will probably say the same.

Mike


Um, yea, I'm one of AA guys and I "definitely" will say that AAs keep a fire going all summer without a problem.

Mike, you have been around long enough to know the virtues of the AA/AHS without resorting to the "probably" clause!!! :D Or at least certainly know the attitudes of the Axeman men and how they feel about their boilers. Come on, you can do it, admit they're just as good as the EFMs, only different!!!
Townsend
 
Stoker Coal Boiler: Axeman Anderson 260
Coal Size/Type: Pea / Buck

Re: Best way to do DHW

PostBy: Pacowy On: Tue Nov 05, 2013 1:44 pm

whistlenut wrote:A tankless can cause a solid fuel appliance to overheat if there is the normal showers, cooking, cleanup, dishwasher.........then nothing for a load as the day warms up. Sure a dump zone could be added, but I prefer the indirect especially since you could have additional demands down the road. I really think folks underestimate the domestic hot water needs of a typical home. Today's tighter homes sure seem to be top heavy on the domestic demand, vs the heat load. Just one old man's opinion... :idea: I might add that I burn 24/7/365 so I like to avoid the summer condensation issues in equipment.


I agree fully with Doug on the condensation issues and the tendency of many people to underestimate or overlook the significant load placed on a boiler by DHW requirements. On the issue of overheating due to DHW load, I can't say I ever saw that with an EFM; I'll defer to Doug on whether that's more of an AA/AHS issue.

Mike
Pacowy
 
Stoker Coal Boiler: H.B. Smith 350 Mills boiler/EFM 85R stoker
Coal Size/Type: Buckwheat/anthracite

Re: Best way to do DHW

PostBy: Townsend On: Tue Nov 05, 2013 1:44 pm

Sting wrote:option one as it is provides NO SCALD PROTECTION

Very dangerous
Image

Dangerous? So is excessive consumption of alcohol.

Mitigate the possible scalding with a mixing valve. Mitigate the drinking with a designated driver and line up a liver donor.

Townsend
 
Stoker Coal Boiler: Axeman Anderson 260
Coal Size/Type: Pea / Buck

Visit Lehigh Anthracite