Wood/Propain to Coal W/AA130

Been reading this forum for awhile, reviewed many options and decided to make the jump to coal. Been heating home with propane boiler, hot water coil in air handler and indirect DHW heater until $$$$ for propane in
2006. Fired up a radiant wood stove in the basement every year since burning 2.5 to 3.5 cords to heat 2700 sq ft of 1st and 2nd floors by cutting an opening in the return air duct close to stove. Natural convection most
of the time and warm floors from the radiant heat [basement toasty]. Much to the families delight [and wife] we will put the aa130 with coal bin in a shed right outside the house. Need 30ft of piping in house and roughly
12 outside up into shed. I would like to burn 24/7/365 for heat and DHW. I did read all the excellent thoughts posted to "needs help asap". Bought a 1960 AA130 from Glenn Harris [what a guy, thanks Glenn] and going
over that unit, few bushings, seals and gaskets. OK> I will be parralleing into the existing boiler. Any thoughts on pipe size? Running circulator all the time or just when one of the 3 loops calls for heat? Circulator size?
[ the shed floor will be lower then the 1st floor due to outside grade by 2 ft or 6 ft above boiler } Using black pipe vs. copper in the house? Dump zone ??? I will put radiators in the basement now since the wood stove is retired
to occasinal hot dog duty. Should we use the original design of controls on the boiler or go electronic? [should I have multible posts?]

Welcome to the forum.

Do you know the model/specs of the coil in your air handler? Most water-to-air heat exchangers have an advertised output (btus per hour) based on a certain flow and temperature. What model indirect are you using?

The pipe size and circulator choice will depend on the load. Considering your relatively short underground run, you might want to call a local outdoor-wood-boiler dealer and see if they have any partial rolls of insulated, oxygen-barrier pex.

Lots of questions here.

Need to break this down.

The load on the unit determines everything. Add up the load of the three zones. This will be in BTU's per hour. Do calculations, not just on existing equipment size.
If one of the zones is DHW, then how it is piped and controlled matters to sizing the system. If on a priority zone that takes over from the heating zones, then size on worst case of heating zones only with a safety for the DHW load.
Then figure out the delta t you want the system at. Typically 20 degrees is the norm. BTUH/(500*deta-t)=gpm for plain water. Based on GPM you size the pipe. Total pipe / valves/ equipment friction loss at a given gpm is how you size the pump.

I would run a control conduit to the shed with your piping. A low voltage interlock that triggers the aquastat on the boiler when any zone wants heat will save you a ton of coal (or two).

Black Vs copper? = Skills vs wallet.

Current copper prices have changed my mind set.

I will occassionly use copper for 1" and smaller if existing piping is copper and there is only a small amount of it. Otherwise I look at PEX with an oxygen barrier for heating. Regular PEX is ok for domestic water.

I have gone to Black iron for 1-1/4" and larger. Takes more time but I have all of the tools I need. It will save some money on material but is slightly more labor intensive.

Controls -Heck go with WEB based full digital controls if you want. I find that simple electro-mechanical controls work for me. They have been around for years and years and are as economical and reliable as anything else.

Edit - I spent 12 years in the commercial building control industry. Done all types of controls. Motto is "Too clever is dumb".

Rob R. wrote:Welcome to the forum.

Do you know the model/specs of the coil in your air handler? Most water-to-air heat exchangers have an advertised output (btus per hour) based on a certain flow and temperature. What model indirect are you using?

The pipe size and circulator choice will depend on the load. Considering your relatively short underground run, you might want to call a local outdoor-wood-boiler dealer and see if they have any partial rolls of insulated, oxygen-barrier pex.

The coil is a 80,000 BTU at 14,000 cfm, Crown boiler is 125k BTU and DHW is an Amtrol WH7-P.
Sure, I can pick up any length section of pipe for the outside run.

Anthony

steamup wrote:Lots of questions here.

Need to break this down.

The load on the unit determines everything. Add up the load of the three zones. This will be in BTU's per hour. Do calculations, not just on existing equipment size.
If one of the zones is DHW, then how it is piped and controlled matters to sizing the system. If on a priority zone that takes over from the heating zones, then size on worst case of heating zones only with a safety for the DHW load.
Then figure out the delta t you want the system at. Typically 20 degrees is the norm. BTUH/(500*deta-t)=gpm for plain water. Based on GPM you size the pipe. Total pipe / valves/ equipment friction loss at a given gpm is how you size the pump.

I would run a control conduit to the shed with your piping. A low voltage interlock that triggers the aquastat on the boiler when any zone wants heat will save you a ton of coal (or two).

Very good ideas, I will have a coal boiler installer calculate it out and do some of the work. Like the KISS option myself for controls.