Component Test; Bypass Humidifier Mode; Dehumidification Mode; Zone Mode - Carrier 58MVP Installation, Start-Up, And Operating Instructions Manual

a. Call for continuous fan—The thermostat closes R-G
circuit.
b. Blower on—The blower starts immediately.
NOTE: The blower starts at approximately 400-500 RPM. After
20 sec, the motor is turned off for 1/10 of a sec where a coast down
calibration is done to evaluate resistance of the conditioned air
duct system. The microprocessor then determines blower RPM
required to provide proper airflow for heating mode.
NOTE: The continuous fan speed is the same as low-heat speed
unless it is field adjusted to another desired airflow. See Continu-
ous Fan Setup Switches section. There is also a chart on wiring
diagram. (See Fig. 24.)
c. Electronic Air Cleaner—The EAC-1 terminal is ener-
gized whenever blower operates, regardless of operating
mode.
2. Operating with continuous fan (R-G) and call for heat
(R-W/W1) is received—Same as heat pump mode except
blower on delay is 10 sec less than heat mode. After call for
heat (R-W/W1) is terminated, the blower remains operating at
low-heat speed for selected blower off delay before resuming
continuous fan speed.
3. Operating with continuous fan (R-G) and call for cooling
(R-Y/Y2) is received—See Cooling Mode section. After call
for cooling (R-Y/Y2) is terminated, the blower remains
operating at cooling speed for 90 sec before resuming con-
tinuous fan speed.
Step 8—Component Test
All components are functionally operated except gas valve with
component test feature.
This feature helps diagnose a system problem in case of a
component failure.
NOTE: Setup switch SW-1 MUST be in OFF position or Fault
Code 22 (setup error) will occur.
NOTE: NO thermostat signal may be present at control center,
and all blower time delay off periods must be completed.
To initiate component test feature, proceed with the following:
1. Leave 115-v power to furnace turned on.
2. Remove main furnace door.
3. Remove blower access panel.
4. Move setup switch SW-6 to ON position.
5. Manually close blower access panel door switch. Use a piece
of tape to hold switch closed.
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. Failure to follow this warning could result in
personal injury or death.
When items 1-5 have been completed, the following will occur:
1. The control center goes through a brief self-test. This self-test
takes approximately 2 sec to complete. After door switch is
closed, red (microprocessor) LED briefly comes on. Then
green LED comes on for 1 sec, followed by 1 sec where both
green and yellow LEDs are on. During this time, the micro-
processor is checking itself.
2. Inducer motor operates for 20 sec at low speed, operates for 20
sec at high speed, then turns off.
3. Hot surface ignitor is energized for 15 sec, then de-energized.
4. Main blower motor operates for 20 sec at low speed, operates
for 20 sec at high speed, then turns off.
5. After component operation test is completed, 1 or more fault
codes (11, 22, 41, or 42) will flash. See service label on back
of main furnace door for explanation of fault codes.
NOTE: To repeat component test, turn setup switch SW-6 to OFF
and then back to ON.
After component test, perform the following:
1. Release blower panel access door switch and turn setup switch
SW-6 to OFF position.
2. If applicable, replace blower access panel and check LED
status by removing plug in blower access panel.
3. Reinstall main furnace door if all LEDs are off, indicating
furnace is ready to operate when a signal from thermostat is
received.
Step 9—Bypass Humidifier Mode
When setup switch SW-3 BPH is in ON position, RPM calculated
for low heat is multiplied by 1.15 for all furnace model sizes. This
compensates for increased return-air temperature caused by by-
passed air supply.
Step 10—Dehumidification Mode
→
A dehumidification input is provided via a 1/4 in. male quick-
connect terminal labeled DEHUM located next to the transformer
secondary connections. The DEHUM input acts differently de-
pending on which style of variable speed furnace control you have.
The older style variable speed furnace control shown in Fig. 27,
DOES NOT have a DE connection while the newer style variable
speed furnace shown in Fig. 27, has a DE connection. The newer
style variable speed furnace control is expected to be available by
mid 1998. Both of these variable speed furnace controls function
the same except the DEHUM logic is reversed. This logic reversal
has come about from historical use of a standard humidistat to do
dehumidification since the contacts open on high humidity, thus
removing the 24-v signal to initiate dehumidification.
On the older style variable speed furnace controls a field supplied
relay is required between the thermidistat or humidistat control and
furnace. The relay coil is connected between DHUM output on the
thermidistat control and C
humidistat output and C
normally closed contact is connected between R and DEHUM
terminals on the furnace control (see Fig. 27 and 28). When a
dehumidify demand exists, relay is de-energized and normally
closed contacts supply 24-v to the furnace DEHUM terminal. As
a result, the furnace control reduces the blower airflow by 15
percent to 340 CFM per ton during continuous fan or cooling
operation.
On newer style variable speed furnace controls, a field supplied
relay IS NOT required. The DEHUM output on the thermidistat
control or the humidistat output, is connected directly to the
DEHUM terminal on the furnace control. In addition, the DE
jumper located next to the DEHUM terminal must be removed to
enable the DEHUM input (See Fig. 27 and 29). When a dehu-
midify demand exists, the furnace control reduces the blower
airflow by 21 percent to 315 CFM per ton during continuous fan
or cooling operation.
This blower speed reduction compensates for high humidity
conditions during cooling operation on all furnace model sizes.
Reference Thermidistat™ Control Installation, Start-Up, and Op-
erating Instructions for further details.
Step 11—Zone Mode
When setup switch SW-5 MZ is in ON position, blower motor
control is the same as above except with the following exceptions:
35
terminal on the furnace control or the
OM
terminal on the furnace control. Its
OM