Looking for some constructive criticism

[nate p.]

First I'd like to say I wasn't sure if I should post this here or the boiler section. I bought a new house last year. It had a very old pellet stove in it 1991 Englander 25-pfs
And the house is a little too big to heat with it by itself efficiently. My main furnace is propane and that is pretty old as well. My plan is to eventually move to an outdoor boiler but that isn't in the budget right now. I'm trying to reduce my propane usage to as close to zero as possible because I guess I'm cheap and if I can why not..... So basically I've been toying around with the idea of making my pellet stove a boiler so to speak. It is a dinosaur and has a regular 6" flue. My plan was to coil copper pipe around the flue that seams to lose an excessive amount of heat then run water through that to a storage tank in basement then to a heat exchanger in the furnace. I know I know seems kinda redneck but I thought I'd like an outside point of view and any other ideas on this topic. And before it's pointed out no, a newer more efficient pellet stove or wood stove is not in the budget at the moment.sorry for the crude drawing but it may better explain my thoughts

 

[peakbagger]

Yes it can be done..... And now the inevitable BUT. The heat transfer system has to be made safe and that means an expansion tank and pressure/temperature relief valves are required. An air separator is a nice thing also as the alternative is a bubble forms in the pipes and in the least is noisy and at worse can cause weird stuff to happen. You potentially need to be worried about overcooling your stack gases which can lead to acidic condensate having to be dealt with.

 

[mikkeeh]

A space requires x btus to heat. You say your pellet stove wont do that. Do you think you can capture enough byus to make a difference?