Intertek ACVC96 Service Instructions Manual page 41

SYSTEM OPERATION
F O M
AN NLY 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 continuous fan speed
following a five (5) second delay. Electronic air cleaner
terminal is energized.
• Circulator blower runs, integrated control module moni-
tors safety circuits continuously.
• R and G thermostat contacts open, completing the
call for fan.
• Circulator blower is de-energized. Electronic air
cleaner terminal is de-energized.
D M
EHUMIDIFICATION ODE
The normal operational sequence in dehumidification mode
is as follows:
1. R and Y1/G or Y1+Y2/G thermostat contacts close,
initiaing a call for cool.
2. Integrated control module performs safety circuit checks.
3. Outdoor fan and compressor are energized to their ap-
propriate speed.
4. Circulator blower is energized on the appropriate cool
speed at the level and time determined by the selected
ramping profile. Electronic air cleaner terminals are en-
ergized with circulator blower.
5. Furnace circulator blower and outdoor cooling unit run
their appropriate speed, integrated control module moni-
tors safety circuits continuously.
6. Dehumidistat opens on humidity rise allowing the fur-
nace circulator blower to operate at 85% of the cooling
speed during combined thermostat call for cooling and
dehumidistat call for dehumidification.
7. Humidistat opens on humidity fall allowing furnace cir-
culator blower to switch back to normal cooling speed.
8. R and Y1/G or Y1+Y2/G thermostat contacts open, com-
pleting the call for cool.
9. Outdoor fan and compressor are de-energized.
10. Circulator blower continues running during a cool off de-
lay period. The OFF delay time and airflow level are de-
termined by the selected ramping profile.
11. Electronic air cleaner terminals and circulator blower
are de-energized.
12. Furnace awaits next call from thermostat.
HEATING - A
BNORMAL
The following presents the probable causes of questionable
furnace operation and how to fix them. Look through the
observation window in the blower access door and make a
note of the error code displayed on the dual 7-segment dis-
O
PERATION
play. Next, refer to the Troubleshooting Chart - ComfortNet™
on the following pages for an interpretation of the code dis-
played on the LED's for a description of the problem.
NOTE: Use caution when reading the diagnostic codes from
the furnace control's dual, 7-segment LED's. The position
of the control within the furnace can lead to a misinterpreta-
tion of the error codes. With the control in an orienation as
shown below, codes on the dual, 7-segment LED's are read
left to right.
1 2 R
Memory Card Connector
Dual 7-Segment LED's
1. Internal Control Failure with Integrated Ignition
Control. Check for voltage to the furnace and low volt-
age at the control board. Check for blown fuse on the
control board. If the control determines it has an internal
fault, it enters a locked-out state. Any of the situations
mentioned will cause the dual, 7-segment LED's to be
off. The control board should only be replaced only after
all other checks from the Troubleshooting Chart -
ComfortNet™ have been verified.
2. System Lockout. If a flame is not sensed during the
first seven (4) seconds after the gas valve is energized,
the control turns off the gas. There will then be a 30
second delay while the induced draft blower is energized
to purge the heat exchanger. The ignitor will again be
energized and preheated for an additional (1) second.
The gas valve will then be energized. If flame is not sensed
DE
C G Y1 Y2 O
W1 W2
HUM
41