Component Tests - Carrier 58MCB Service And Maintenance Instruction

Fig. 18—Inducer Housing Drain Cap
Fig. 19—Funnel in Drain Tube and Antifreeze
Running Through Trap
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to unit
components.
Make sure limit switch wire does not contact any metallic
component such as the gas valve. If wire is shorted, the 3-amp
fuse on furnace control board will blow and the unit will not
operate.
To retrieve previous codes, remove 1 of the red main limit wires
for 1 to 4 sec until the LED light goes out, then reconnect it. (Do
not leave red wire disconnected for longer periods of time as the
control will assume an overtemperature condition exists and will
respond with blower operation.) This places the control in the
status recall mode and displays the first code stored in memory.
Record the code. After the last code is displayed the control will
perform the component test, and then return to normal standby
mode.
COMPONENT TEST
NOTE: The furnace control component test allows all compo-
nents to run for a short time; except the gas valve and humidifier
terminal HUM are not energized for safety reasons. The EAC-1
terminal is energized when the blower is energized. This feature
helps diagnose a system problem in case of a component failure.
The component test feature will not operate if any thermostat
signal is present at the control and not until all time delays are
completed.
NOTE: Record the status code BEFORE opening the blower
access door and before shutting off power to furnace. Opening the
blower access door will open the blower door switch and shut off
power within the furnace. When power to the furnace is shut off by
either method, the status code will be lost because the code is not
stored while power is removed for any reason.
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To Begin Component Self-Test:
ELECTRICAL SHOCK AND UNIT MAY NOT
OPERATE HAZARD
Failure to follow this warning could result in electrical shock,
personal injury, or death.
Blower access panel door switch opens 115-v power to
control board. No component operation can occur. Caution
must be taken when manually closing this switch for service
purposes.
1. Remove blower access door.
2. Disconnect the thermostat R lead from furnace control board.
3. Manually close blower door switch.
4. For approximately 2 sec, short (jumper) the C
on control to the TEST/TWIN 3/16-in. quick-connect terminal
on control until LED turns off. Remove jumper from termi-
nals. (See Fig. 16.)
NOTE: If TEST/TWIN and C
longer than 2 sec, LED will flash rapidly and ignore component
test request.
Component test sequence for single-stage furnace is as follows:
a. LED will display status code 11 four times.
b. Inducer motor starts and continues to run until Step f. of
component test sequence.
c. After 7 sec the hot surface igniter is energized for 15 sec,
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then off.
d. Blower motor operates on HEAT speed for 10 sec.
e. Blower motor operates on COOL speed for 10 sec.
f. Inducer motor stops.
5. Reconnect R lead to furnace control board, remove tape from
blower door switch, and reinstall blower door.
6. Operate furnace per instruction on outer door.
7. Verify furnace shut down by lowering thermostat setting
below room temperature.
8. Verify that furnace restarts by raising thermostat setting above
room temperature.
12
-24v terminal
OM
-24v terminals are jumpered
OM