System schematic of an open vented system with a boiler and a solid fuel stove as the heat source. The system has two central heating zones with radiators, a domestic hot water (DHW) cylinder and a heat leak radiator.
There is a heat leak radiator on the gravity fed circuit to ensure that the solid fuel stove can dissipate its heat if no zones are calling. The DHW cylinder is also on the gravity fed circuit of the solid fuel stove and acts as a heat leak of the stove. Since the cylinder has two coils it can also be heated by the boiler when the solid fuel stove is not burning. The heat leak radiator is connected on the solid fuel stove’s return, after the DHW cylinder. This ensures that the cylinder has priority and that any excess heat is dumped using the radiator when the cylinder is hot. The Non-Return Valve on the secondary DHW coil is used to prevent any back circulation of the stored hot water from drifting back out of the cylinder to the system.