CONTROL PANEL OPERATING PROCEDURES
8/1/99
3-8
Figure 3.13
Blower Proof Switch Location
6. Simultaneously, the AIR FLOW LED on the
combustion safeguard lights, and the unit
begins its 7-second purge cycle.
7. At the end of the purge cycle, the
combustion safeguard initiates a 10 second
trial for ignition and the following
simultaneously occurs:
•
The LCD displays the message IGNITION
TRIAL.
•
The combustion safeguard PTFI LED lights
•
The ignition transformer energizes.
•
The air/fuel valve rotates to ignition position,
engaging the Ignition position switch and
energizing the safety shut-off valve, (see
Fig. 3.14).
8. Once the combustion safeguard detects
flame, a flame stabilization period of 10
seconds is begun. If at the end of the flame
stabilization period the flame sensor still
detects a flame, the unit is released to
modulate.
At this point, with the unit firing properly, the
FLAME, OPR CNTRL and AIR FLOW LED’s on
the combustion safeguard will be lit and the LCD
display shows the message FLAME PROVEN.
The unit, provided it is in the automatic mode,
will now be controlled by the temperature control
system.
Figure 3.14
Air/Fuel Valve in Ignition Position, Engaging the
Ignition Position Switch
3.10 AFTER FLAME
Once the control signal has dropped below the
stop level (see section 3.12 for Stop Level
explanation), the combustion safeguard closes
the safety shut-off valve extinguishing the flame.
The LED’s on the combustion safeguard will
extinguish. The annunciator display will show
the message STANDBY. The green ON status
indicator light, on the temperature controller,
extinguishes indicating there is no longer a call
for heat.
3.11 START / STOP LEVELS
The start and stop levels are firing rate
percentages that start and stop the unit based
on load. These levels are determined either
manually or automatically through PID controls.
The start level is preset to 25% and the stop
level is preset to 20%. These levels are factory
preset and should not require adjustment.
3.12 AUTO RESTARTS
The unit will automatically restart after the
following faults have occurred:
•
Power failure
•
Water over-temperature
•
High or Low Gas pressure
HARNESS
155
C
NO
154
TO FRAME
A/F VALVE
Summary of Contents for Benchmark G-00-711
Page 62: ...APPENDIX C ix Temperature Sensor Resistance Chart Balco ...
Page 69: ...APPENDIX F xvi ...
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Page 71: ...APPENDIX F xviii ...
Page 72: ...APPENDIX F xix ...
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Page 74: ...APPENDIX G xviii ...
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