LIA231-2
2
1
Bottom Right Corner of Control Board
c. Verify clearance by mounting the control board on the
bottom of the support rail.
d. If clear, remove the bottom mounting bracket from the
control board and re-attach the bracket to the control box.
e. Install the control board into the control box by sliding the
mounting tab on the control board through the slots in the
top of the control box.
f. Attach the control board to the bottom mounting rail of the
furnace control box.
g. Continue on to Step-5 of the installation process.
5. Connect all line voltage, low voltage, and accessory wires.
6. Connect wiring harness edge connector to circuit board.
7. Set blower off delay. Blower off delay DIP switch SW1 is
found near the right-hand corner of the board (see Figure 1).
8. Re-install control box cover.
Note:
Do not connect thermostat wires to control board until
system tests are complete.
System Tests
Step 1: Component Self Test
1. Begin component test sequence by ensuring that thermostat
is turned to OFF position and thermostat wires are
disconnected. Turn power ON and engage blower door
switch. With a short piece of wire, briefly short TEST/TWIN
terminal to Com/24V terminal. The component test sequence
follows:
A. Status LED will flash code and will then turn ON the
inducer motor.
B. Inducer motor will run for the entire component test.
C. Hot surface ignitor and blower motor heat speed will run
for 10 secs.
D. Blower motor cool speed will turn ON for 10 secs.
2. Repair, replace, or service any failing components from the
component self test. The gas valve is not energized during
the self test.
3. Turn power OFF.
4. Disengage the blower door switch.
5. Connect thermostat wires.
6. Install blower door and access door.
7. Turn power ON.
8. Turn gas ON.
Step 2: Flame Sensor Operation
Connect a DC microammeter in series with flame sensor.
Initiate a heat call. After burners ignite and stabilize, measure
flame current. Nominal flame current is between 2.0 and
4.0 microamps DC. If flame current reading is less than 2.0
microamps DC, either replace or remove and clean flame sensor
with a fine grade steel wool. When the flame current falls to 0.5
microamps DC, the furnace control will lock out.
Step 3: System Operation
1. Perform necessary safety checks. Consider flame safety, limit
switch, and vent system.
2. Operate unit through a complete call for heat cycle.
Upflow Condensing Furnaces:
With the blower door(s) removed, locate the LED on the control
board. Check the sides of the casing. You may be able to utilize
the unused condensate drain opening or electrical knock-out as an
observation port on some models. A 1/2-inch electrical box knock-
out plug must be installed when this option is used.
All Furnaces:
1. Measure the height of the floor for upflow furnaces or off the
blower shelf on downflow/horizontal furnaces.
2. Measure the distance from the front inside edge of the casing.
3. Orient the blower door to the correct position and mark this
location on the front of the blower door.
4. Using a step-drill or chassis punch, drill a 1 1/2-inch hole in
the blower door.
5. Install a sight glass in the blower door (Use Carrier Part No.
323017-201 or 323018-201, or equivalent).
6. A 1/2 inch hole may be drilled and an electrical box plug may
be used and are available from hardware stores or electrical
suppliers.
Note:
Do not install an observation port or sight glass through
warning labels on furnace.
CAUTION!
A loose fitting sight glass should be sealed with clear silicone to
prevent leakage and sight glass from falling out.
7. Install Fault Code Label in a convenient location on the
blower door adjacent to the sight glass.
CAUTION!
Do not install a sight glass or observation port between the
furnace and the blower compartment. To avoid having carbon
monoxide drawn into the living area, do not cover any port with
tape, and do not leave the unit unattended and operational with
the blower door off. Failure to follow this warning could result in
possible damage to this equipment, serious illness or personal
injury, or death.
Note:
If a sight glass is not installed, current fault code will be
erased when blower door is removed.
The
ICM281
furnace control has LED fault code capability. To
utilize this feature, it is necessary to field install a sight glass or
observation port. The location of this device will vary depending on
the model of the furnace.
Optional Observation
Port/Sight Glass Installation
Twinning Instructions
A 3/16” quick connect terminal is provided on the
ICM281
control
board for communication between another
ICM281
control board
for furnace twinning.
To configure your control boards for twinning, simply (1) install
each control board according to the installation instructions; (2)
connect the TWIN terminals together (see Fig. 1); and (3) connect
the 24 VAC common together. A common ground between the two
furnaces is also required.
If the 24 VAC supplies to the control are in phase, both furnaces will
turn the blower on and off synchronously and at the same speed.
If the 24 VAC supplies are not in phase, then neither control will
respond to the thermostat commands and the status LED will flash
rapidly.
Figure
1
