tankless vs indirect for DHW in coal boiler

tankless vs indirect for DHW in coal boiler

PostBy: plumber On: Sat Mar 01, 2014 12:37 am

I know the perks of an indirect in a push button boiler, but I'm learning that solid fuel is a lesson in forgetting everything I know. What works better in a coal boiler?
plumber
 
Stoker Coal Boiler: EFM 350

Re: tankless vs indirect for DHW in coal boiler

PostBy: whistlenut On: Sat Mar 01, 2014 12:56 am

Indirects: They are only another zone........ and ALWAYS work MUCH better with any type of fuel. Flattens the loading cycle to 'over time' and not demand.......
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: tankless vs indirect for DHW in coal boiler

PostBy: Lu47Dan On: Sat Mar 01, 2014 12:58 am

plumber wrote:I know the perks of an indirect in a push button boiler, but I'm learning that solid fuel is a lesson in forgetting everything I know. What works better in a coal boiler?

Plumber, I have set up several OWB with heat exchangers to heat the DHW. I used the return water after the A-coil to supply the heat exchanger.
If you have a domestic coil in your boiler then run it, I have run several boilers that have a domestic coil. The system worked well.
I have installed full sized (200,000+ BTU) boilers to heat nothing but DHW. They were Direct systems, the boiler heated the water and sent it to a storage tank, than out to the system.
I have installed Indirect systems off of hot water and steam boilers also. Indirect systems are a little safer as they control the water temperature in the tank. I had to install a mixing valve on the DHW coil on a friends indoor wood boiler as the water coming out of the boiler was way too hot (180°F) going into the system.
I prefer indirect over a DHW Coil.
Dan.
Lu47Dan
 
Hand Fed Coal Stove: Sears circulator air tight stove.
Other Heating: Crown 115,000 BTU oil fired boiler(house) Weil Mclain 150,000BTU oil fired boiler(Shop)


Re: tankless vs indirect for DHW in coal boiler

PostBy: whistlenut On: Sat Mar 01, 2014 1:08 am

Dan, you are right on OWB's. 250 gallons of 180 water is impressive.......and I like your plan to install on the return line. Plate exchangers don't even tax an idling boiler that big. Size DOES Matter.
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: tankless vs indirect for DHW in coal boiler

PostBy: plumber On: Sat Mar 01, 2014 1:18 am

Right now I'm circulating between the tankless to a 40 gallon storage tank. In the winter, I know I would benefit with the ability to prioritize the hot water zone. However in the summer it seems like my boiler runs off the timer and the circulator just runs. I'm averaging 600 lbs per month in the summer.
plumber
 
Stoker Coal Boiler: EFM 350

Re: tankless vs indirect for DHW in coal boiler

PostBy: Lu47Dan On: Sat Mar 01, 2014 1:37 am

whistlenut wrote:Dan, you are right on OWB's. 250 gallons of 180 water is impressive.......and I like your plan to install on the return line. Plate exchangers don't even tax an idling boiler that big. Size DOES Matter.

Yep, I have posted in another thread that I do not like plate exchangers on high mineral content water, I installed a shell and tube heat exchanger in a friends dairy last week. The water heater started leaking, I took one of mine from inventory and installed it to replace the water heater. After all he had heat in the milking parlor, courtesy of his OWB. I had a SS one, It was certified for food service, so it is acceptable for that use.
His wife loves it, unending hot water, at around 140°F. He is going to order a new one and than install a more advanced control system on it.
Dan.
Lu47Dan
 
Hand Fed Coal Stove: Sears circulator air tight stove.
Other Heating: Crown 115,000 BTU oil fired boiler(house) Weil Mclain 150,000BTU oil fired boiler(Shop)

Re: tankless vs indirect for DHW in coal boiler

PostBy: Rob R. On: Sat Mar 01, 2014 5:53 am

Tankless coils work well with boilers that have sufficient mass and btu output. I don't think the LL110 has enough of either to provide satisfactory performance without a holding tank.

The smaller the boiler, the more advantage an indirect will have.
Rob R.
 
Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy

Re: tankless vs indirect for DHW in coal boiler

PostBy: CapeCoaler On: Sun Mar 02, 2014 2:00 am

If you have a large draw...
Go indirect...
Cape Cod...
Summer and beaches...
All the guests and outdoor showers and all the indoor ones too...
We never run out...
CapeCoaler
 
Stoker Coal Boiler: want AA130
Hand Fed Coal Stove: DS Machine BS#4, Harman MKII, Hitzer 503,...
Coal Size/Type: Pea/Nut/Stove

Re: tankless vs indirect for DHW in coal boiler

PostBy: Lightning On: Sun Mar 02, 2014 2:03 pm

Would somebody please educate me? What does indirect hot water heating mean in this thread and does it imply that there is a "direct" way to heat water in this context? :D

Interested in growing my knowledge.. Thanks!
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: tankless vs indirect for DHW in coal boiler

PostBy: lsayre On: Sun Mar 02, 2014 2:10 pm

Lightning wrote:Would somebody please educate me? What does indirect hot water heating mean in this thread and does it imply that there is a "direct" way to heat water in this context? :D

Interested in growing my knowledge.. Thanks!


An indirect hot water tank has no heat source of its own. Its internal heating coils are connected to a zone valve (or zone circulator), the same for which is activated by an aquastat probe immersed into the indirect hot water tank. The boiler sees it merely as another zone. This type of HWT is indirectly heated via the boiler.

As opposed to this, a typical HWT has its own internal 'direct' heat source.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Stockton Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: tankless vs indirect for DHW in coal boiler

PostBy: Lightning On: Sun Mar 02, 2014 2:17 pm

lsayre wrote:An indirect hot water tank has no heat source of its own.
OK.. so would this be what I call a "temper tank" in my set up with a thermo siphon and water coil in the fire box?
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: tankless vs indirect for DHW in coal boiler

PostBy: lsayre On: Sun Mar 02, 2014 2:19 pm

Lightning wrote:
lsayre wrote:An indirect hot water tank has no heat source of its own.
OK.. so would this be what I call a "temper tank" in my set up with a thermo siphon and water coil in the fire box?


Not if you also have a hot water tank with its own internal heat source.
lsayre
 
Stoker Coal Boiler: AHS S130 Coal Gun
Coal Size/Type: Stockton Anthracite Pea
Other Heating: Resistance Boiler (13.5 KW)

Re: tankless vs indirect for DHW in coal boiler

PostBy: Lightning On: Sun Mar 02, 2014 2:23 pm

lsayre wrote:Not if you also have a hot water tank with its own internal heat source.
Oh ok, so what I have is a hybrid indirect hot water system.. :lol: My preheated temper tank water feeds the electric tank which then may or may not use any electric based on how warm my preheated water is..
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: tankless vs indirect for DHW in coal boiler

PostBy: Carbon12 On: Sun Mar 02, 2014 2:24 pm

An indirect is like a domestic hot water coil in a boiler but in reverse. Instead of the large volume of water in the boiler heating the DHW in the coil, the indirect has the coil heat the larger volume of water for DHW.
Carbon12
 
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

Re: tankless vs indirect for DHW in coal boiler

PostBy: Rob R. On: Sun Mar 02, 2014 2:26 pm

They also make reverse indirect water heaters. :)
Rob R.
 
Stoker Coal Boiler: EFM DF520
Hand Fed Coal Stove: Hitzer 50-93
Coal Size/Type: Lehigh Rice
Other Heating: Dad's 1953 EFM Highboy