Solaronics Suntube low-intensity heaters are powered by a positive pressure burner which fires into 4″ diameter by 5′ or 10′ long steel tubes. Burner ignition is accomplished by pilotless direct spark. Combustion air is supplied to the system by a centrifugal blower and fixed air inlet orifice. A standard 4″ diameter inlet air collar allows for connection to outside air without the use of supply fans. The system is approved for either directly vented or indirectly vented operation without the use of a vacuum pump. The power burner along with combustion chamber, heat exchangers and reflectors comprise the entire heater. These heaters are design certified by the American Gas Association, Canadian Gas Association and are described by separate literature.
Low Intensity Burner
The low-intensity burner utilizes a 1/25th HP, 120V AC single phase-60Hz motor and centrifugal blower which provides 148 CFH free air with a 1.47 full load AMP draw on A & B Series and 138 CFH free air with a 1.33 full load AMP draw on C Series. A fixed air orifice plate regulates the appropriate air required for combustion. Gas is introduced to the burner by a two stage redundant gas valve. Gas is then regulated by two orifices, an easily accessible subsidiary orifice sized for the appropriate length and BTUH rating of the burner and a fixed main orifice. Air and gas are thoroughly mixed in a spiral motion by the burner core assembly and are then ignited by direct spark at the ignition module.
Burner operation is monitored and controlled by an ignition detection control. When the thermostat calls for heat, power is applied to the blower motor. A dual air flow switch continuously monitors the air supply. When adequate inlet air and flue back pressure are present, the ignition detection control is energized and institutes a 15 second pre-purge cycle. This is followed by a 35 second trial for ignition during which a spark is developed at the ignition module and the gas valve is opened to the first step of its two stage operation. Gas is then ignited and approximately 5 seconds later the gas valve stages to its second and final operation position. A flame rod, part of the ignition module senses flame presence and the ignition detection control shuts off the spark current and monitors continued flame presence. Should flame failure, blocked flue or blocked inlet air occur during ignition or normal operation, the ignition detection control will close the gas valve and lock out the system. The system will remain locked out
Three system monitoring lights indicate normal burner operation. When lit, these monitoring lights indicate normal conditions for power on; inlet air and flue back pressures; and gas valve on. A burner inspection sight glass also allows for visual inspection of the flame and ignition module.