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I. DESCRIPTION
The Berner Gas-Fired Door Heater is designed to instantly
direct a stream of heated air toward a large door opening,
when the door is opened in cold weather. It utilizes a ring type
burner operating on natural gas. The propeller is a special
Ductaxial solid aluminum casting, direct connected to an in-
dustrial duty, totally enclosed motor.
The burner is the product of many years of experience in the
crop drying field with direct-fired burners.
Products of combustion, which are discharged directly into
the main airstream, consist of carbon dioxide and water va-
por. At maximum rated heat output the concentration Of C0
2
is approximately 2000 PPM (parts per million) compared -
with a maximum allowable* of 5000 PPM.
Although the water vapor of combustion is added, relative hu-
midity is actually reduced, owing to the heat that is added to
the air . At maximum rated heat output, and assuming 60º F.
saturated entering air, the discharge air is less than 5% RH.
II. MOUNTING POSITIONS
(A) Burner: The standard unit may be installed at any
angle between horizontal and vertical down airflow. The
control cabinet is on the left-hand side, facing the air-
stream. The back panel of the cabinet must lie in a verti-
cal plane; (i.e., the burner house cannot be rotated, thus
rolling the cabinet toward the top or bottom of the burner
house).
(B) Plumbing: The gas piping elbows up and into the
burner house on the bottom centerline. During installa-
tion, by loosening the union just outside the heater, the
piping train may be rotated to any desired direction, pro-
vided valves are properly oriented.
(See CAUTION )
III. INSTALLATION (MECHANICAL)
One Door Heater will handle up to approximately a 12' x 15'
door opening. Larger opening require two or more heaters.
CAUTION: No door heater can substitute for a Tempered
Intake Air Unit. If in-plant negative pressure exists because
of exhaust ventilation, makeup air must be provided before a
door heater can be expected to function properly. See your
Berner representative.
The heater should be aimed at a spot on the floor about four or
five feet inside, and midway across, the door. At the inlet end
there should be no obstructions to the airflow closer than 20"
- 24"; at the outlet end, of course, there should be nothing
obstructing the airstream. Around the sides of the heater
there should be no combustible material closer than three
feet.
IV. GAS PRESSURE REGULATO R
Gas supply pressure must be specified at the time of order-
ing, so that the proper regulator can be furnished to reduce
line pressure to 6” - 8” W. C.
It is suggested that a 1/8" or 1/4" I.P.S. test connection be
provided in the gas supply line upstream of the regulator to
facilitate taking pressure readings at time of startup and ad-
justment of burner equipment.
Make sure that the regulator is installed in the line with the
arrow on the body pointing in the direction of the flow of the
fuel.
With the regulator properly installed in the line, the following
procedure is suggested when ready to light off and adjust the
burner.
(A) Remove the “top cap” of the regulator and check for
shipping block or rod installed between spring and top
cap. Remove, if found.
(B) Remove plug, in vent opening of diaphragm housing.
(Connect vent to atmosphere, if required by plant or insur-
ance regulations. See Suggestions for Regulator Vent-
ing).
The setting of the spring beneath the “top cap” on the regula-
tor determines the outlet pressure. Screwing in on it increase
the outlet pressure. Screwing out reduces the outlet pres-
sure. The outlet pressure from the regulator will not neces-
sarily be the same at full fire as under static conditions of no
flow. Therefore, when adjusting gas pressure to very heat
output, do so with the heater in operation. (See Maintenance.)
Although most regulator problems in the field have to do with
insufficient pressure at the outlet (usually because of line
losses), it is well to know what to do in case the regulator
won’t deliver a low enough pressure: Turning it upside down
in the line will frequently do the trick.
V. SUGGESTIONS FOR REGULATO R
VENTING
(See also Safety Devices on vent valve)
One purpose of the vent connection is to provide a safe means
of venting gas if the regulator diaphragm should fail. The vent
also provides relief from the space above the diaphragm as it
moves during regulation. A restriction in the vent line can
result in poor regulator performance.
The vent line should normally be piped outside the building,
with as short a run of pipe as possible. There should be a
minimum number of bends, and the pipe should be as large
as practical, using the vent hole size as a guide. When tub-
ing is used (on the smaller regulators), care must be exer-
cised to avoid sharp bends and the resultant reduction in area.
Grouping vent lines together into a common header is not
normally recommended. If they must be grouped, the header