CLEAN AND CHECK HEATING UNIT FOR 2 UNITS, 4YR AND 13YR. CLEAN AND CHECK BURNERS AND BURNER OPERATION. CHECK THERMOSTAT, AIR FILTER, HUMIDIFIER, HEAT EXCHANGER, HIGH LIMIT CONTROL, GAS PRESSURE, AND ALL ELECTRICAL CONNECTIONS. ADJUST BLOWER COMPONENTS, AND LUBRICATE ALL NECESSARY MOVING PARTS. REPLACED 2 CAPACITORS.