Furnace circulator blower and outdoor cooling unit run, integrated control module monitors safety circuits continuously.
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five second on delay. Electronic air cleaner terminals are energized with circulator blower.
Circulator blower is energized on cool speed following a fixed
• R and Y thermostat contacts close, initiating a call for cool.
• Integrated control module performs safety circuit checks.
• Outdoor fan and compressor are energized.
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The normal operational sequence in cooling mode is as follows:
COOLING MODE
Furnace awaits the next call from thermostat.
XVII. SAFETY CIRCUIT DESCRIPTION
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Burner Flame
If the furnace is operating in high-stage heating mode when the thermostat contacts open, the circulator blower remains at high heat speed for thirty seconds. The circulator blower then switches to low heat speed for the remainder of the selected heat off delay period. For example, the selected heat off delay period is 150 seconds. The circulator blower operates at high heat for 30 seconds and at low speed for 150 - 30 = 120 seconds.
Check the
Burner Flames for:
1. Stable, soft and blue.
2. Not curling, floating or lifting off.
Circulator blower is de-energized following a heat off delay period (selectable 100 or 150 seconds; factory set at 150 seconds).
If the furnace is operating in the low-stage heating mode when thermostat contacts open, circulator remains at low heat speed for the selected delay off period.
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Induced draft blower is de-energized following a fifteen second post purge.
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R and W thermostat contacts open, completing the call for heat.
Furnace is now operating in high-stage heating mode.
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XVI. OPERATIONAL CHECKS
If low-stage delay period expires, control will shift operation from low-stage heating mode operation to high-stage heating mode operation. Control will energize circulator blower high heat speed and high stage gas valve.
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Furnace awaits the next call from thermostat.
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safety circuits continuously.
terminals are de-energized.
Furnace operates; integrated control module monitors
Circulator blower is de-energized. Electronic air cleaner
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Furnace is now operating in low-stage heating mode.
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R and G thermostat contacts open, completing the call for fan.
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fixed thirty second blower on delay. Electronic air cleaner terminals are energized with circulator blower.
safety circuits continuously.
Circulator blower is energized on low heat speed following a
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Circulator blower runs, integrated control module monitors
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will remain open only if flame is detected.
air cleaner terminals are energized.
Integrated control module monitors flame presence. Gas valve
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Circulator blower is energized on low heat speed. Electronic
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• R and G thermostat contacts close, initiating a call for fan.
• Integrated control module performs safety circuit checks.
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up period, delivering gas to burners and establishing flame.
Low and high-stage gas valves open at end of igniter warm
Igniter warm up begins after 15 second prepurge expires.
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period causing pressure switch contacts to close.
Furnace awaits the next call from thermostat.
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Induced draft blower is energized for 15 second prepurge
second cool off delay period. Electronic air cleaner terminals are de-energized.
Integrated control module performs safety circuit checks.
Circulator blower is de-energized following a fixed forty five
R and W thermostat contacts close, initiating a call for heat.
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Outdoor fan and compressor are de-energized.
The normal operational sequence in sequence is as follows:
R and Y thermostat contact open, completing the call for cool.
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The integrated control module is an electronic device which, if a po- tential safety concern is detected, the module will take the necessary precautions and provide diagnostic information through an LED.
INTEGRATED CONTROL MODULE
A number of safety circuits are employed to ensure safe and proper furnace operation. These circuits serve to control any potential safety hazards and serve as inputs in the monitoring and diagno- sis of abnormal function. These circuits are continuously moni- tored during furnace operation by the integrated control module.
GENERAL
The burner flames should be inspected with the burner compart- ment door installed. A sight glass is provided for inspection pur- poses. Flames should be stable, quiet, soft, and blue (dust may cause orange tips but they must not be yellow). Flames should extend directly outward from the burners without curling, floating, or lifting off. Flames must not impinge on the sides of the heat ex- changer firing tubes.
BURNER FLAME
The normal operational sequence in fan only mode is as follows:
FAN ONLY MODE
(MODE DIP SWITCH IS SET TO “2 STG”
POSITION)
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