About this deal
Your not by any means the first to think of recovering heat from the flue, but the only ones who are successful in doing it are the appliance manufacturers and many of them have had their woes in attempting it. i was going to fit one on those back boilers to my garden heater but it will boil the water unless there are sufficient radiators to heat soak! Finance is provided by PayPal Credit (a trading name of PayPal UK Ltd, Whittaker House, Whittaker Avenue, Richmond-Upon-Thames, Surrey, United Kingdom, TW9 1EH).
The 6" Magic Heat Reclaimer is a single piece unit that is quickly and easily installed in-line with new or existing single wall stove pipe of any air-tight stove, furnace, or freestanding fireplace.degree bend straight out of the wall behind it 8inches hole through the wall with Midtherm followed with a y piece incorporating a sootbox and then up onto the roof all in 8inch outer 6 inch i/d stainless pipe 1inch rockwool insulation works a treat! If I understand his description correctly, he has no chimney; the pipe just goes out through the side wall. My bucket was tapered , so one end of the the unit has a 11-1/4" diameter and the other end is 10-1/2" diameter. Flue gases go through the tubes (firetube design) and the 55 gallon barrel has a 6" flue on either end for connection to the stove and chimney.
I started a fire in my outdoor fire pit, poked some holes in the bottom of the bucket, and placed the bucket upside down on the fire.try to make it indestructible (HTP high heat coatings come to mind) and expensive, or just accept that it's eventually going to be a casualty so make it cheap and replaceable.
If you do make it, get the aluminized pipe, and figure out a way to simply clamp the tubes in place, no welding on the tube. Racking out burning coals when the water circulation has stopped is not fun, I have done it, lucky the Aga was on a quarry tiles floor so any burning coals spilt would not cause a fire, but once you add a boiler, then water must flow. Perhaps any steel box (even an empty "barrel stove") could house a few of these coils, and have an access door for cleaning.When I had it serviced, the guy used a gas analyser, it was sitting around 90% combustion efficiency.