Instruction manual

2. Turn off electrical supply to furnace.
3. Turn off gas supply to furnace.
Failure to turn off the gas and electric supply may result in
explosion, fire, death or personal injury.
4. Remove furnace blower and control access doors.
5. Remove control box cover.
6. Disconnect thermostat and humidifier (if equipped) wires.
7. Disconnect line voltage, blower, EAC, (if equipped) and
transformer wires.
8. Remove wiring harness edge connector and gasket from
circuit board.
9. Remove retaining screws and old circuit board.
10. Inspect control and control box for evidence of water staining.
11. Correct any sources of water leakage (humidifier, evaporator
coil, vent system) into the control area.
Step 2—Installing the New Control
1. Ground yourself! Handle circuit board by edges.
2. For 90 percent efficient furnaces, clip JW9 jumper wire. JW9
jumper is located near right-hand corner of circuit board below
HUM-1 terminal. (See Fig. 1.) This will provide 15 sec
inducer off delay.
3. Insert edge of board between tabs of control box.
4. Install circuit board retaining screws.
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
located near right-hand corner of board. (See Fig. 1.)
8. Re-install control box cover.
9. Do not connect thermostat wires to control board until
Start-up and System Check-out is complete.
SYSTEM CHECK-OUT
Step 1—Component Self Test
1. To initiate component test sequence, ensure thermostat is
turned OFF or 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.
Component test sequence is as follows:
a. Status LED will flash code then turn ON inducer motor.
b. Inducer motor will run for entire component test.
c. Hot surface ignitor and blower motor-heat speed will run
for 10 sec.
d. Blower motor-cool speed will be turned on for 10 sec.
2. Repair or replace or service any component that fails during
the self-test. The gas valve is not energized during self-test.
3. Turn power off.
4. Disengage blower door switch.
5. Connect thermostat wires.
6. Install blower and access doors.
7. Turn power back on.
8. Turn on gas.
Step 2—Flame Sensor Operation
Connect a DC microammeter in series with flame sensor. Initiate
a call for heat. After burners ignite and stabilize, measure flame
current. Nominal flame current is between 4.0 and 6.0 microamps
DC. If flame current is below 4.0 microamps DC, remove and
clean flame sensor with fine steel wool, or replace flame sensor.
The furnace control will lock-out when flame current falls to 0.5
microamps DC.
Step 3—System Operation
1. Perform any other safety checks as deemed necessary (flame
safety, limit switch, vent system etc.).
2. Run unit through 1 complete call for heat cycle.
OBSERVATION PORT/SIGHT GLASS INSTALLATION
(OPTIONAL)
NOTE: If a sight glass is not installed, current fault code will be
erased when blower door is removed.
Replacement furnace control Part No. CESO110057-02 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.
Step 1—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-in. electrical box knock-
out plug must be installed when this option is used.
Step 2—All Furnaces
1. Measure height of LED off the floor for upflow furnaces or off
the blower shelf on downflow/horizontal furnaces.
2. Then measure distance from front inside edge of casing.
3. Orient blower door to correct position and mark this location
on front of blower door.
4. Using a step-drill or chassis punch, drill 1 1/2-in. hole in
blower door.
5. Install a sight glass Part No. 323017-201 or 323018-201 in
blower door.
6. A 1/2-in. 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. If a warning label interferes with the
observation port, use an alternate location such as side of casing.
Or, a 1/4-in. hole may be drilled in blower door and then plugged
with a 5/16- X 1/2-in. long screw providing it does not interfere
with instructions or control board.
7. A loose fitting sight glass should be sealed with clear silicone
to prevent leakage and sight glass from falling out.
8. Install Fault Code label (see Fig. 2) in a convenient location on
blower door adjacent to sight glass.
Do not install a sight glass or observation port between the
blower compartment and the furnace vestibule. Do not cover
any port with tape. Do NOT run the unit unattended with the
blower door off. Carbon Monoxide may be drawn into living
space. A failure to follow this warning could result in possible
damage to this equipment, serious personal injury, or death.
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