Control methods and apparatus for gas-fired combustors

A method for controlling the operation of an apparatus for causing a circulating heat transfer medium to transfer heat, for delivering heat to a space in response to a heating load being imposed on the space, the method comprising the steps of:

• providing a burner for fluid fuel, operably connected to a source of fluid fuel;
• modulating the flow of fluid fuel from the source to the burner;
• enabling the transfer of heat from the burner to the heat transfer medium, by conducting the heat transfer medium in a heat transfer relationship to the burner;
• circulating the heat transfer medium, from the means for enabling transfer of heat, to a position remote from the burner, for transfer of at least some of the heat, from the heat transfer medium, at the remote position;
• circulating the heat transfer medium back to the means for enabling heat transfer;
• and
• modulating the circulation of the heat transfer medium, for varying the amount of heat transferred from the heat transfer medium,
• the modulation of the fuel flow and the circulation of the heat transfer medium being operably controlled by control means, between at least three rates of operation, other than a zero flow rate,
• the modulation of the fuel flow and the circulation of the heat transfer medium further being operably controlled so as to be capable of occurring during a single heating cycle towards a continuous balancing of heat being supplied to the space with heating loads being imposed on the space.

A method for controlling operation of a burner for fluid fuels, for heating a heat transfer medium to a desired temperature, for delivering heat to a space in response to a heating load being imposed on the space, the method comprising the steps of:

• providing an initial amount of fuel to the burner and igniting the fuel to begin burner operation;
• supplying further fuel to the burner at a predetermined initial flow rate;
• transferring heat from the burner to the heat transfer medium by passing the heat transfer medium through a heat exchanger heated by the burner;
• circulating the heated heat transfer medium along a predetermined flow path;
• monitoring the temperature of the heat transfer medium at the heat exchanger, at which heat from the burner is transferred to the circulating heat transfer medium;
• monitoring the temperature of the heat transfer medium at a position remote from the heat exchanger;
• substantially simultaneously modulating the rate of supply of the fuel to the burner, and modulating the rate of circulation of the heat transfer medium along the predetermined flow path, so as to control the temperature of the heat transfer medium to a predetermined temperature condition.
• the modulation of the fuel flow and the circulation of the heat transfer medium being operably controlled by control means between at least three rates of operation, other than a zero flow rate,
• the modulation of the fuel flow and the circulation of the heat transfer medium further being operably controlled so as to be capable of occurring during a single heating cycle towards a continuous balancing of heat being supplied to the space with heating loads being imposed on the space.