Sterling TUBULAR GAS FIRED DIRECT SPARK PROPELLER UNIT HEATERS GG-30 - Manual (Page 31)

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OPERATION
POWER VENTED PROPELLER UNITS
DIRECT SPARK IGNITION
EXPLANATION OF CONTROLS (See Figure 25):
1. Each Unit Heater comes equipped with a power
vent system that consists of a power venter motor
and blower, pressure switch, and sealed flue
collector in place of the conventional draft diverter.
2. The power venter motor is energized by the room
thermostat through the integrated control board
when a demand for heat is sensed. The pressure
switch measures the flow through the vent system
and energizes the direct spark ignition system
beginning the pre-purge timing when the flow
is correct.
T h e p r e s s u r e s w i t c h M U S T
NOT be bypassed. The unit MUST NOT be fi red
unless the power venter is operating. An unsafe
condition could result.
3. The direct ignition system consists of an ignition
control module and a gas valve. When the pre-purge
period ends, the spark ignition system is energized,
and the gas valve opens to supply gas to the burner.
When the thermostat is satisfi ed, the vent system is
de-energized and the valve closes to stop the fl ow of
gas to the unit.
4. The limit switch interrupts the fl ow of electric current
to the control board, interrupting the fl ow of gas to the
gas valve if the unit heater becomes overheated.
5. The flame roll-out switch interrupts the flow of
electric current to the control board, interrupting
the flow of gas to the unit heater in the event of
sustained flame roll-out from the burner area. If
this switch trips, DETERMINE AND CORRECT
THE CAUSE of the fl ame roll-out.
6. Once the thermostat is satisfi ed, or the limit switch
interrupts the fl ow of electric current to the control
board, the unit will begin a post-purge period. When
the post-purge period ends, the power venter motor
is de-energized.
7. The fan operation is delayed 30
seconds once the thermostat is
closed, and continues operation
for 30 seconds after the thermostat
opens. The start-up fan delay
must not exceed 30 seconds
from a cold start.
8. The wall ther mostat, supplied optionally, is a
temperature sensitive switch that operates the
vent system and ignition system to control the
temperature of the space being heated. The
ther mostat must be mounted on a ver tical,
vibration-free surface free from air currents and in
accordance with the furnished instructions (also
refer to Electrical Section).
START-UP (Also refer to lighting instruction plate
equipped on the unit)
1. Open the manual gas valve in the gas supply line to
the unit heater with union connection loose, purge
air from the gas line. Tighten the union and check
for leaks.
Never use an open fl ame to detect
gas leaks. Explosive conditions may exist which
could result in personal injury or death.
2. Open the manual valve on the unit heater.
3. Turn ON the electrical power.
4. The unit should be under the control of the
thermostat. Turn the thermostat to the highest point
and determine that the power venter motor starts
and the burner ignite. Turn the thermostat to the
lowest point and determine that the power venter
motor shuts off and the burner is extinguished.
5. Turn the thermostat to the desired position.
6. See Gas Input Rate and Adjustments sections.
SHUT DOWN
1. Turn the valve selector lever to the “OFF” position.
2. Turn off the electricity.
3. To relight, follow “start-up” instructions.
See Figure 25 for parts/identifi cation.
Figure 25