CLEAN AND CHECK HT. CHECK THERMOSTAT, CHECK ALL ELECTRICAL CONNECTIONS, CHECK BURNERS AND BURNER OPERATION. CHECK HEAT EXCHANGER, CHECK HIGH LIMIT CONTROL, CHECK AIR FILTER, CHECK GAS PRESSURE AND FOR PROPER VENTING. CHECK HUMIDIFIER. ADJUST BLOWER COMPONENTS, LUBRICATE ALL NECESSARY MOVING PARTS. REPLACED DEFROST CONTROL BOARD AND BULB. EVERYTHING IS RUNNING GREAT. RENEWED SERVICE AGREEMENT.