A gas heater (10) includes heater burner (16). Heat is generated by the ignition of gas supplied to the burner via conduits (20). A solenoid gas safety valve (22), when provided with a threshold electrical current, is maintained in an open condition allowing passage of gas to the burners. When not provided with that threshold current, the valve is closed, preventing the passage of gas. An electrical current generator (28) includes spaced apart thermocouple devices (30, 32). Due to a combined electrical current generation by the thermocouples, the current generator can generate electrical current at least said threshold current even if any one of the thermocouple devices does not generate the threshold electrical current.