SYSTEM OPERATION
18
Alarm Display
If an active alarm is present, the alarm code shall be report-
ed in Status Menu starting with “E” and following with the
appropriate two digit alarm code.
Clearing Faults
While in the Last 6 Faults option menu, push & hold the
center button for 5 seconds. This will clear all non-active
alarm(s) in the Last 6 Faults menu. The display will flash
three times to confirm faults have been cleared.
Learn Menu
Using this option resets the communicating network which
will cause the furnace to discover what devices are present
on ClimateTalk™ network. This menu will not appear when
the furnace control is connected to a Non-Comm OD unit.
Code Release Number Menu
This is a reference only menu to display the firmware
release revision numbers for each micro-controller.
Constant Fan Speed Menu
This menu allows for adjustment of the multiplier for con-
stant fan operation in 10% increments. Each furnace has
a “Maximum CFM” determined by motor HP. All fan opera-
tions are based off of multipliers which are percentages of
this number. Max CFM is shown below. The default con-
stant fan multiplier is 25%.
Model
Max CFM
3 Ton Models
1400
4 Ton Models
1760
5 Ton Models
2200
Gas Heat Airflow Multiplier Menu
The menu is used to change the gas heat airflow
multiplier for gas heat operation. In most cases the
default gas heat airflow will provide a temperature rise
near the middle of the acceptable range. The multiplier
will be expressed by the 2
nd
& 3
rd
characters of the display
as a percentage of max CFM.
Gas Heat Fan Off Delay Menu
The default setting is 90 seconds. The available adjustment
range is from 30 to 180 seconds in 30 second increments.
Gas Heat Fan On Delay Menu
The default setting is 30 seconds. The available adjustment
range is from 5 to 30 seconds in 5 second increments.
Gas Heat Trim Factor Option Menu
Gas Heat airflow may be trimmed from -10% to +10% in
2% increments.
Gas Heat Stage Multiplier Menu (CFM)
This menu allows adjustment of the low fire CFM multiplier.
The default CFM for low fire is 70% of high fire.
Gas Pressure Test Menu
This menu allows 100% firing rate be locked in to check
gas valve pressure.
CAUTION
T
O
PREVENT
UNRELIABLE
OPERATION
OR
EQUIPMENT
DAMAGE
,
THE
INLET
GAS
SUPPLY
PRESSURE
MUST
BE
AS
SPECIFIED
ON
THE
UNIT
RATING
PLATE
WITH
ALL
OTHER
HOUSEHOLD
GAS
FIRED
APPLIANCES
OPERATING
.
Natural Gas Minimum: 4.5" w.c. Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.
INLET GAS SUPPLY PRESSURE
NORMAL SEQUENCE OF OPERATION
Power Up
•
120 VAC power applied to furnace.
•
Integrated ignition control performs internal checks.
•
The control board will display I D L. awaiting a call from
the thermostat
•
Integrated ignition control monitors safety circuit
continuously.
•
Furnace awaits call from thermostat.
Heating Mode
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.
•
Pressure Sensor Verification:
The control operates
the inducer in a manner to verify the pressure sensor
null value and span operation are within specification.
If the system is operating correctly, this test takes only
a few seconds. If the system is not functioning properly,
the control times out after a maximum 90 seconds and
display the proper fault code.
•
Induced draft blower is energized for 30 second
prepurge.
•
Igniter warm up begins after 30 second prepurge expires.
•
Gas valves open 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 detected.
•
Circulator blower is energized on high heat speed
following a fixed 30 second blower on delay. Electronic
air cleaner terminal is energized with circulator blower.
