The 20,000 BTU Non-Vented Greenhouse Heater is an open flame heater that does not need to be vented. Although it does require a fresh or combustible air intake form the outside of the greenhouse.
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 additional 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.
