Abstract: An auxiliary heater with a casing enclosing internal components which components include a heat exchanger separate from and outside the coolant tank and wherein two coolant loops each have their own coolant pumps and wherein a potable water loop exchanges heat with coolant within the heat exchanger. A control circuit provides enhanced coolant flow through the heat exchanger when the call for hot water is significant without significantly reducing the temperature of the hot water being used. A level switch within the coolant tank prevents coolant pumps from running without pump coolant and a filling and air purging operation improves the initial filling operation of the auxiliary heater with coolant and also prevents the coolant pump from running dry. A user switch may dedicate the hot coolant from the coolant tank to either the production of hot potable water or it may share both hot water and space heating.

Abstract: An auxiliary heater with a casing enclosing internal components which components include a heat exchanger separate from and outside the coolant tank and wherein two coolant loops each have their own coolant pumps and wherein a potable water loop exchanges heat with coolant within the heat exchanger. A control circuit provides enhanced coolant flow through the heat exchanger when the call for hot water is significant without significantly reducing the temperature of the hot water being used. A level switch within the coolant tank prevents coolant pumps from running without pump coolant and a filling and air purging operation improves the initial filling operation of the auxiliary heater with coolant and also prevents the coolant pump from running dry. A user switch may dedicate the hot coolant from the coolant tank to either the production of hot potable water or it may share both hot water and space heating.

Abstract: An auxiliary heater with a casing enclosing internal components which components include a heat exchanger separate from and outside the coolant tank and wherein two coolant loops each have their own coolant pumps and wherein a potable water loop exchanges heat with coolant within the heat exchanger. A control circuit provides enhanced coolant flow through the heat exchanger when the call for hot water is significant without significantly reducing the temperature of the hot water being used. A level switch within the coolant tank prevents coolant pumps from running without pump coolant and a filling and air purging operation improves the initial filling operation of the auxiliary heater with coolant and also prevents the coolant pump from running dry. A user switch may dedicate the hot coolant from the coolant tank to either the production of hot potable water or it may share both hot water and space heating.