The DFM14E and DFM44E temperature control systems are for use with recirculating, direct gas-fired, modulating air heaters and are designed to comply with ANSI Z83.18 specifications. The auto-calibrate feature gathers damper position data and airflow data, which is then used to generate each unit’s airflow characteristic. The systems have custom-engineered, microprocessor-based logic controls. Other features of these systems are 24/7 programmable thermostats, remote room sensing (optional), multiple air metering options, Fahrenheit and Celsius selectable, low-pressure burner compensation, low-fire start timer, occupied/unoccupied mode, and mild weather relay (optional).