A sander can include a housing, an indicator disposed on the housing, and a motor assembly in the housing. The main gas pipe or the gas pipe section is open to supply gas to the gas burners when the main switch is actuated while a gas supply to the gas burners is interrupted when the main switch is actuated once again. Each of a pair of secondary pawls has the same construction as the primary pawls and is configured to be driven into engaged and disengaged positions by corresponding camming surfaces of the secondary cam.