Boiler Choice???

Hello All

I burned 1000gals propane last year, from varios conversion charts it converts to about 3.8 tons of coal or so, for that 6 month period.
I have forced hot air. I wan't to put a water heat ex coil in the plenum and use a coal boiler, for heat and DHW year round.( the largest coil I can put in the plenum is 18x18 80k/btu/hr @1200CFM)
Is the Kaa2 large enough or will I have to go with the KA6. 3.8 ton works out to about 1 40# bag a day for 6 months some days more some less depending on outside temp.
The house is 4 years old 2 story colonial, good insulation and windows. If the 3.8 ton conversion was right I will need to order the unit this week.
The lead time now is late Sept early Oct. I will also be going the Coal-Trol route to keep temp fairly constant and coal useage minimal, the coal use seems low to me.
Has anyone who uses a water coil in their plenum found there to be any noticeable loss of flow due to coil resistance, there is an "A" coil in there now which will stay for the AC.

thanks

eskimo

Is the KAA-2 large enough? YES the biggest problem people have is over sizing. Make the unit operate close to rated capacity an it will be more efficient. Don't be afraid and go with the Kaa2 oldtimers will always push the bigger units, a big mistake....

Remember you can always tap off with some hot water base board for the basement. Make sure you leave some capped tees on both supply and return for later use.

You may have to put in a larger motor on the fan if the static pressure loss from coil slows down the air flow. I said a larger motor size same air flow. Try if first before you worry about it. Don't worry about a problem before you have it.