which coal boiler to get

whew! I never knew heating with coal could be so complicated. I didn't want to get involved as I'm not an engineer, but just take a look at what thousands of outdoor wood boiler guys are using to heat rickety old farmhouses. They are using the cheap 1" pex pipe with a Taco 007 pump and it works fine. Don't forget the hotter the boiler water the more heat it carries. More coal used too, but look at the cost comparison of buying the most expensive materials up front vs. efficiency losses and you'll probably never save that much coal to cover the added expense. BTW now is a good time to buy pex pipe, nobody likes sitting on rolls of it all summer.

If I remember correctly, the human body gives off about 400 BTU..... the heat loss for my dining room is about 4,600 BTU.... Let's see.... can I get about about a dozen of you deep thinkers to drop by each Saturday for hydronic study?

1" Pex pipe and 1" Pex Al Pex Pipe have substantially different inside diameters. You will get substantially more flow with the Pex Al Pex. 1" Pex Al Pex is nearly the same size as 1 1/4" Pex.

Pex Al Pex inside diameter is: 1.03 inches (for Kitec brand pipe)

1" Pex pipe inside diameter is: 0.87 inces (for Raupex brand pipe)

1 1/4" Pex pipe inside diameter is 1.07 inches (for Raupex brand pipe)

An additional advantage of Pex Al Pex is that it is much more demensionally stable with temperature change than Pex pipe. The oxygen barrier in Pex Al Pex pipe is interior to the pipe and not subject to damage from handling and installation while the oxygen barrier on Pex pipe is simply a coating on the outside of the pipe and is subject to damage as the pipe expands and contracts or when it is pulled during installation.

Thanks Bob,, I didn't know that, Ithought all of the Pex products were described by inside dimension. I definitely like working with the Pex-al-Pex, you can straighten it, or bend it and it will stay put.. the regular Pex can be like wrestling a snake..

Greg L

Greg L, Let me ask you should I go with the continues loop or the keystoker comes with a hotwater coil and the Harman is a add on. If I want to heat hot water in non home heating time then the loop has to run to heat DHW???? Thanks Brian Two pex or four pex?????????????????????????????????????????????????????????????????????

As I get this new system up and running Coalburner I have been reading your articles for about two years but have never talked to you one on one are you out there will need coal??

26Weeks wrote:Greg L, Let me ask you should I go with the continues loop or the keystoker comes with a hotwater coil and the Harman is a add on. If I want to heat hot water in non home heating time then the loop has to run to heat DHW???? Thanks Brian Two pex or four pex?????????????????????????????????????????????????????????????????????

stokerscot wrote:To keep the wiring simple, these are the wires that I would run from house to out building.
1. 4-#14 wires. green,white,black,red. Power for the boiler(black) and an additional circuit for lights,recepticles, whatever(red). That's two 15amp circuits. Or 3-#12 instead to give one 20 amp circuit.
2. 6-# 18 wires, three pair. One pair to use as a T-T jumper for summertime domestic water operation. Two pair for spare.
You can make it much more complicated but this is simplistic. Use thhn wire sold at the Depot or Lowes. Have them cut to length. Add extra on to measurement as contrary to what they say, there is no wire stretcher. Hope this helps. Scott

The #14 wire should that be solid or straned wire.Were moving forward. Thanks Brian

Hello Brian, how far away from the house's boiler and DHW heater will the Keystoker be?? If you have say 100' of Pex in the ground, then you will have 200' of pex in the circulation loop.

So if you don't have the water circulating continously, then you will have a significant amount of cool to cold water that will need to be purged and heated each time you use DHW. Sou you may have to wait 5-10 minutes for hot water, depending on the length of the pex, how long since hot water was used, and how hot the coal boiler is at that time [begining aor end of a cycle].

The best method would be to install an indirect hot water heater, and use an aquastat in this heater to turn on the circulator to the Keystoker.. And don't buy the water coil for the coal boiler, save the money and use it towards the Indirect hot water heater. The regular water loop for heat will be used to heat the indirect hot water heater,


Greg L

OR>>>>>>

You could install a super insulated tank in the house basement - say 250 to 500 gallon - dependent on use and recharge goal.

Heat that to 200 degrees and use it to heat your DHW to 125 - when the tank gets to 140 - you refire your coal boiler and recharge the mass storage tank with energy.

In theory you could idle the boiler all week at 140 to 160 degrees but then once every (two??) days -- again dependent on DHW use and storage - you could ramp the girl up to 180-200 heat the loop and charge the storage tank...


opps there I go with primary / secondary piping again... Sorry - its a habit I guess

LsFarm wrote:Hello Brian, how far away from the house's boiler and DHW heater will the Keystoker be?? If you have say 100' of Pex in the ground, then you will have 200' of pex in the circulation loop.

So if you don't have the water circulating continously, then you will have a significant amount of cool to cold water that will need to be purged and heated each time you use DHW. Sou you may have to wait 5-10 minutes for hot water, depending on the length of the pex, how long since hot water was used, and how hot the coal boiler is at that time [begining aor end of a cycle].

The best method would be to install an indirect hot water heater, and use an aquastat in this heater to turn on the circulator to the Keystoker.. And don't buy the water coil for the coal boiler, save the money and use it towards the Indirect hot water heater. The regular water loop for heat will be used to heat the indirect hot water heater.


Greg L

Greg I ordered 100 feet of pex-al-pex today. The building will require about 60 feet with one run or I could do it with two 50 foot runs. But I think that I will go with one and sell whats left over. Then go with two flat plate heaters is that what is meant by a indirect water heater? One heater intersepting return water to propane boiler and the other to heat DHW. Brian

Sting wrote:You could install a super insulated tank in the house basement - say 250 to 500 gallon - dependent on use and recharge goal.

Heat that to 200 degrees and use it to heat your DHW to 125 - when the tank gets to 140 - you refire your coal boiler and recharge the mass storage tank with energy.

In theory you could idle the boiler all week at 140 to 160 degrees but then once every (two??) days -- again dependent on DHW use and storage - you could ramp the girl up to 180-200 heat the loop and charge the storage tank...

TARM USA has a lot of stuff for heat storage, tanks and systems.

coaledsweat wrote:

Sting wrote:You could install a super insulated tank in the house basement - say 250 to 500 gallon - dependent on use and recharge goal.

Heat that to 200 degrees and use it to heat your DHW to 125 - when the tank gets to 140 - you refire your coal boiler and recharge the mass storage tank with energy.

In theory you could idle the boiler all week at 140 to 160 degrees but then once every (two??) days -- again dependent on DHW use and storage - you could ramp the girl up to 180-200 heat the loop and charge the storage tank...

TARM USA has a lot of stuff for heat storage, tanks and systems.

I have a new propane hot water heater I was going to dump 180 degree water into it and use a mixing valve on the out going side? Brian

26Weeks wrote:I have a new propane hot water heater I was going to dump 180 degree water into it and use a mixing valve on the out going side? Brian

I would be careful if you have a well. Mixing valves can be problematic with high levels of hardness and require frequent maintenance to keep them working properly.

26Weeks wrote:

stokerscot wrote:To keep the wiring simple, these are the wires that I would run from house to out building.
1. 4-#14 wires. green,white,black,red. Power for the boiler(black) and an additional circuit for lights,recepticles, whatever(red). That's two 15amp circuits. Or 3-#12 instead to give one 20 amp circuit.
2. 6-# 18 wires, three pair. One pair to use as a T-T jumper for summertime domestic water operation. Two pair for spare.
You can make it much more complicated but this is simplistic. Use thhn wire sold at the Depot or Lowes. Have them cut to length. Add extra on to measurement as contrary to what they say, there is no wire stretcher. Hope this helps. Scott

The #14 wire should that be solid or straned wire.Were moving forward. Thanks Brian

Either or . They will both accomplish the purpose. If you don't have help, the stranded can be a Pita Scott
Btw, how big did you end up making your outbuilding?

26Weeks wrote:I have a new propane hot water heater I was going to dump 180 degree water into it and use a mixing valve on the out going side? Brian

Not big enough

and the HS Tarm equipment - while plug and play - it too darn expensive.

Figure big storage and use it to heat your DHW heater to 125 so you don't need to worry about the family pink parts when the problematic mixing valves fail.