CAME OUT ON A SERVICE CALL FOR 2 HT UNITS, 4 YR, AND 5YR. NEW SERVICE AGREEMENT. LUBRICATE ALL NECESSARY MOVING PARTS AND ADJUST BLOWER COMPONENTS. CHECK THERMOSTAT, AIRFLOW, AIR FILTER, ENERGY CONSUMPTION, HEAT EXCHANGER, HIGH LIMIT CONTROL, FAN CONTROL, AND ALL ELECTRICAL CONNECTIONS. CLEAN AND CHECK BURNERS AND BURNER OPERATION. CHECK MANIFOLD GAS PRESSURE AND FOR PROPER VENTING. EVERYTHING IS OPERATING GREAT.