Some of you may recognize the grill lid from the first attempt at a wood fired pool heater. Same lid, turned upside down. Serpentine coils are the same ones I used in the first build as well.

I have reused the Intex suction and return fittings, so I don't have any over the wall plumbing. Much easier, no priming needed.

The firebox, just starting to burn.

I add a slight restriction to the air intake, to increase the air flow speed for a more complete burn.

Look! No smoke when burning well! According to others who work with Rocket Mass Heaters, this is usually an indication of a full burning of all the volatiles from the wood.

With a good burn going, I get an average 5* temperature rise, intake to return in the pool. I am planning on insulating the pipes, to reduce the heat loss back to the pool, as well as insulating the outside of the heat exchange box (grill lid). This should increase the utilization of the heat available.