Upon arrival the technician performed a dual seasonal heating safety inspection. The technician tested the safeties for the larger system for the left side of the house, the system has no issues. The technician been checked the smaller system for the right side of the home, the technician found that the toggle switch for the gas valve was set to off. The technician turned on the gas valve, system is working properly at this time. The technician tested the safeties, safety is working properly at this time. The technician spoke with the customer and the customer stated that the day after we replaced the gas valve for the water heater, The water became a lot cooler again. The technician found that the left water heater was not lit at the time of visit, the technician let the water heater. Water heater is working properly at this time but The technician has concerns about the gas valve.