Adjustments; Set Gas Input Rate - Carrier 58MCB Installation, Start-Up, And Operating Instructions Manual

Fig. 44—Inducer Housing Drain Cap
Fig. 45—Filling Condensate Trap
NOTE: Record the status code BEFORE opening the blower
access door and before shutting off power to the 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.
To Begin Component Self-Test:
ELECTRICAL SHOCK 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 center. 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.
3. Manually close blower door switch.
4. For approximately 2 sec, short (jumper) the C
on control to the TEST/TWIN 3/16-inch quick-connect termi-
nal on control until the LED goes out. Remove jumper from
terminals. (See Fig. 34.)
NOTE: If TEST/TWIN and C
longer than 2 sec, LED will flash rapidly and ignore component
test request.
Component test sequence is as follows:
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a. LED will display previous status code 4 times.
b. Inducer motor starts and continues to run until Step g of
component test sequence.
c. After 7 seconds the hot surface igniter is energized for 15
sec., then off.
d. Blower motor operates on Continuous-FAN speed for 10
sec.
e. Blower motor operates on HEAT speed for 10 sec.
f. Blower motor operates on COOL speed for 10 sec.
g. Inducer motor stops.
5. Reconnect R lead to furnace control, remove tape from blower
door switch, and re-install 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.
Step 5—Adjustments

SET GAS INPUT RATE

Furnace gas input rate on rating plate is for installations at altitudes
up to 2000 ft.
In the U.S.A., the input ratings for altitudes above 2000 ft must be
reduced by 2 percent for each 1000 ft above sea level.
In Canada, the input ratings must be derated by 5 percent for
altitudes of 2000 ft to 4500 ft above sea level.
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Furnace input rate must be within ±2 percent of input on furnace
rating plate adjusted for altitude.
1. Determine natural gas orifice size and manifold pressure for
correct input.
a. Obtain average yearly gas heat value (at installed altitude)
from local gas supplier.
b. Obtain average yearly gas specific gravity from local gas
supplier.
44
-24v terminal
OM
-24v terminals are jumpered
OM