Domestic heating boiler with alternate heat sources - uses gas, electric or oil heating in conjunction with wood burning hearth to raise temp. of heat transfer fluid

摘要

The boiler is used to heat a heat transfer fluid and uses at least two alternate heat sources. One of the heat sources is provided by a wood-burning hearth while the other uses electricity, gas and/or fuel oil. The heat transfer fluid may be air, with a conduit (10) for its passage running below the wood burning hearth (2). The other heat source is positioned at the end of this conduit (10) providing additional heating. Pref. the admission conduit (10) running beneath the hearth (2), is used to supplement the draught, and communicates with a passage (13) at the back of the hearth (2). The passage (13) is limited on one side by a panel (8) having good heat conduction, for heat transfer from the hearth with fins (16) projecting into the passage. The appts. incorporates electric heating elements (23, 24, 25) which are used in conjunction with the wood-burning hearth or in preference to it.