CLEAN AND CHECK HEATING UNIT, CHECK BURNERS AND BURNER OPERATION, CHECK THERMOSTAT, AIR FILTER, AIRFLOW, HUMIDIFIER, AND ALL ELECTRICAL CONNECTIONS. INSTALLED 2.5 GAS PKG PREM, ENSA. MADE SURE SYSTEM WAS INSTALLED PROPERLY. MADE SURE WORK AREA WAS CLEANING WHEN FINISH, EVERYTHING IS WORKING GOOD.