30
6. Verify proper temperature rise as outlined in
Section XIV,
Startup Procedure and Adjustment - Temperature Rise
.
Orange
High
Common/Neutral
Medium Low
Circulator Blower Speeds
Low
Red
Medium Blue
Black
White
XV. NORMAL SEQUENCE OF OPERATION
P
OWER
U
P
The normal power up sequence is as follows:
•
115 VAC power applied to furnace.
•
Integrated control module performs internal checks.
•
Integrated control module flashes LED one time.
•
Integrated control module monitors safety circuits
continuously.
•
Furnace awaits call from thermostat.
H
EATING
M
ODE
The normal operational sequence in heating mode is as follows:
•
R and W thermostat contacts close, initiating a call for heat.
•
Integrated control module performs safety circuit checks.
•
Induced draft blower is energized for 15 second prepurge
period causing pressure switch contacts to close.
Humidifier terminals are energized with induced draft blower.
•
Igniter warm up begins after 15 second prepurge expires.
•
Gas valve opens at end of igniter warm up period, delivering
gas to burners and establishing flame.
•
Integrated control module monitors flame presence. Gas
valve will remain open only if flame is sensed.
•
Circulator blower is energized on heat speed following a
fixed thirty second blower on delay. Electronic air cleaner
terminals are energized with circulator blower.
•
Furnace runs, integrated control module monitors safety
circuits continuously.
•
R and W thermostat contacts open, completing the call for
heat.
•
Gas valve closes, extinguishing flame.
•
Induced draft blower is de-energized following a fifteen
second post purge. Humidifier terminals are de-energized.
•
Circulator blower is de-energized following the heat off delay
period (selectable 90, 120, 150, 180; factory set at 150).
Electronic air cleaner terminals are de-energized.
•
Furnace awaits next call from thermostat.
C
OOLING
M
ODE
The normal operational sequence in cooling mode is as follows:
•
R and Y thermostat contacts close, initiating a call for cool.
•
Integrated control module performs safety circuit checks.
•
Outdoor fan and compressor are energized.
•
Circulator blower is energized on cool speed following a
fixed five second on delay. Electronic air cleaner terminals
are energized with circulator blower.
•
Furnace circulator blower and outdoor cooling unit run,
integrated control module monitors safety circuits
continuously.
•
R and Y thermostat contacts open, completing the call for
cool.
•
Outdoor fan and compressor are de-energized.
•
Circulator blower is de-energized following a fixed forty five
second cool off delay period. Electronic air cleaner terminals
are de-energized.
•
Furnace awaits next call from thermostat.
F
AN
O
NLY
M
ODE
The normal operational sequence in fan only mode is as follows:
•
R and G thermostat contacts close, initiating a call for fan.
•
Integrated control module performs safety circuit checks.
•
Circulator blower is energized on heat speed. Electronic
air cleaner terminals are energized.
•
Circulator blower runs, integrated control module monitors
safety circuits continuously.
•
R and G thermostat contacts open, completing the call for
fan.
•
Circulator blower is de-energized. Electronic air cleaner
terminals are de-energized.
•
Furnace awaits next call from thermostat.
XVI. OPERATIONAL CHECKS
B
URNER
F
LAME
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.
Check the burner flames for:
1. Good adjustment
2. Stable, soft and blue
3. Not curling, floating, or lifting off.
Burner Flame
P
RIMARY
L
IMIT
The primary limit control guards against overheating resulting from
insufficient conditioned air passing over the heat exchanger. If the
primary limit control does not function during this test, the cause
must be determined and corrected. Function of this control should
be verified by gradually blocking the furnace return air after the
furnace has been operating (burners firing) for approximately ten
minutes. Check the control as follows:
1. Allow the furnace to operate with burners firing continuously
for approximately ten minutes.
