Desa Tech DBV250AS is a portable heater designed for use in well-ventilated areas where heated fresh air is needed, without contamination from products of combustion. It features a gear-type fuel pump, a fan to circulate air, a transformer to provide high voltage for ignition, and a solenoid valve to control fuel flow. The heater has a thermostat to automatically maintain the desired temperature, and a purge cycle to cool the combustion chamber and clear it of gases after the heater is turned off.