England here: Boilers of that size for use in woodstoves, here in the UK, are typically able to heat a water pipe coil within a 40 gallon copper, hot water cylinder (thermo-siphon method as you say) in addition to around six decent sized radiators - maybe even up to eight radiators. The radiators would be on a pumped system. A thermostat would be fitted on the output pipe (after the take-off riser to the hot water cylinder), usually set at 60 degrees C (140 F) and when that temperature is detected in the output pipe a thermo-activated switch would turn on the pump. In summer or even Spring and early Autumn (Fall) when the radiator heat isn't required the options would be just to set a low fire for a short while and get a tank of domestic hot water, or to also fit one or two 'heat-leak' radiators at a higher point than the boiler and use them as a heat loss system to prevent over-heating of the domestic hot water tank. They would be part of the thermo-siphon pipework and system, the same system as the hot water tank. They can have shut-off valves so they can be isolated when not required. They are sometimes even sited in an attic, a high point of the property, alongside or above the hot water tank. Hot water tanks are also often sited in attics or alternatively upstairs in a cupboard deliberately built in to the property from the beginning. Usually called an 'airing cupboard'. If the pumped heating system is not required (summer) it is a simple matter to cut the power to the pump via a main switch. Having said all that, hot water tanks are vented at the top with an additional pipe that feeds back into the cold water cistern that feeds the hot tank. The cold cistern is fed from the cold water mains and controlled by a ballcock valve. Too much heat in the hot water causes expansion and the excess is naturally delivered back into the cold cistern. The loss is immediately replaced by the cold pipe that feeds the hot tank from that cold cistern. The cold water cistern also has an overflow pipe (usually to deal with a failed ballcock valve) that allows any excess water to go down that pipe before the cistern overflows. The overflow pipe leads to the outside world.

The firebricks are Vermiculite based. They can be cut with a normal saw. They are expensive but you can make your own. Mixture can be about 80% Vermiculite and 20% Castable Refractory cement (by volume). Just enough water to make a stiff mix. You would have to make some forms to cast them - from plywood.

Thanks so much for this vid! You have made my day.

It's made in the UK . We all have central heating and radiators connected to our water tanks . It's to make domestic hot water and central heating . Not just domestic water

Great info, thanks.

Is it possible for the Esse to heat a 40 gallon hot water tank and a small single radiator simultaneously with the large boiler? And does the boiler to radiator hookup require a pump, or can it work off of thermo siphon as well?

i searched online for 'thermo-front water heater' but found nothing! do you have a link? p.s,. great video, thanks¬

where do I get a thermo front boiler for my stove

Nah i think i will make an S coil with stainless tube would hold more water then them small tanks