The Non-Vented Greenhouse Heater 20,000 BTU is an open flame heater that does not need to be vented. Although it does require a fresh or combustible air intake from the outside of the greenhouse. It is round in design - 12.5 inches in diameter and 22 inches tall, constructed of non-rusting mill polished aluminum shell supporting a stainless steel burner rated at 20,000 B.T.U.
In areas where there is heavy snowfall, it is necessary to arrange to keep the ends of the air intake pipe open. This can be accomplished by tilting something over the outside opening while the snow is falling.
A 2" to 3" PVC air intake pipe should be installed as the figure shows. The outside elbow should be turn down to keep out water and screened to keep out rodents. Intake pipe can be offset to one side. It does not have to be in center of heater. The pipe extending outside must be no more than 12" from inside floor grade, and should stop about three inches from the heater, and about four inches up from the floor.
Single Stage Thermostat - Southern Burner heaters are equipped with millivolt controls and wall mounted thermostat that require no electricity for operation. Two styles are available: The first being a Single Stage Thermostat that has a temperature range of 35 to 75 degrees. When you select a temperature setting the heater will cycle on and off at this setting. Regardless of the time of day or night.
Set Back Thermostat - The Second Style is a Day and Night Set-Back Thermostat. This gives you the capability of two separate temperatures, one for day and one for night. The thermostat has an adjustable clock that you can choose from 15 minute intervals to set the temperature change from day to night settings. The clock is powered by an "AA" Alkaline battery still giving you the convenience of no electricity. Temperature range is from 45 to 90 degrees. Mounting of the thermostat can be up to 25 feet from the heater and should be shielded form direct sunlight or water.
Safety - All controls have a 100% safety cut-off feature. If the pilot flame should go out for any reason, the millivolt control would shut off all gas to the heater. Pilot flame would have to be re-established before heater would operate.
Natural and L. P. Gas - The Non-Vented Greenhouse Heater 20,000 BTU is designed to operate under the side benches, installed flush with the front edge of the growing bench or at the end of the isle. Warning! Heaters on L.P. gas must have a regulator set at II W.C.I. on the L.P. tank.
Heating capacity - In Northern states, it is suggested that one unit be placed for every 150 to 175 square feet of floor space in a conventional greenhouse. In Central states, place on unit heater to every 200 square feet of floor space. In the Southern states, we allow as much as 225 square feet to one unit.
Proper ventilation - Do not over look the necessity of providing a way for fresh air to enter the greenhouse. This is a 'must' and should not be eliminated. Illustrations show the proper way to install the air intake pipe for the Non-Vented Greenhouse Heater 20,000 BTU. A slight top ventilation is also necessary in the greenhouse to provide for circulation and exhaust. In case of heavy snows, take care not to let the vent pipe get buried as the heaters need oxygen to burn properly.
Southern Burner Company's heaters circulate warm air over the greenhouse somewhat like the heat rays from sunshine, from the floor up. They do not radiate heat because radiated heat goes directly to the top glass in the greenhouse and is lost. With the Non-Vented Greenhouse Heater 20,000 BTU the temperature at the top of the greenhouse can be held within 5 to 7 degrees of the floor temperature.
*Note: propane/gas heaters are not as efficient above 7000 foot elevation areas. But modifications to the heaters can be done for areas from 7,000 to 9,000 ft. elevation. Just give us a call for more information.