MAINTENANCE CHECK-UP FOR 4 YR HT UNIT. FOUND A LIL GROWTH. INSTALLED HALO UV, EARNED SERVICE AGREEMENT. EQUIPMENT WAS INSTALLED AND MADE SURE WORK AREA WAS CLEAN WHEN FINISHED. CLEAN AND CHECK BURNERS AND BURNER OPERATION. CHECK MANIFOLD GAS PRESSURE AND FOR PROPER VENTING. CHECK THERMOSTAT, HEAT EXCHANGER, HIGH LIMIT CONTROL, FAN CONTROL, AIR FILTER, AIRFLOW, ENERGY CONSUMPTION, AND ALL ELECTRICAL CONNECTIONS. LUBRICATE ALL NECESSARY MOVING PARTS AND ADJUST BLOWER COMPONENTS. EVERYTHING IS WORKING GOOD.