Defrost Mode; Set-Up Procedures - Carrier 58UHV Installation, Start-Up, And Operating Instructions Manual

NOTE: The furnace control CPU controls blower airflow by
sensing G, Y1, and O for low-cool airflow and G, Y1, Y/Y2, and
O for 2-speed high-cool airflow.
(2.) Terminals EAC-1 and EAC-2 are energized with 115v
when the BLWM is operating at either cooling air-
flow.
(3.) When the thermostat is satisfied, the furnace BLWM
continues operating at the same cooling airflow for an
additional 90 sec.
c. Single-Speed Heat Pump Heating
(1.) The thermostat (and accessory interface kit) R to G-
and-Y/Y2 circuits operate the furnace BLWM at heat
pump heating airflow. Heating airflow is the same as
cooling airflow for airflow selection HP-EFFY and
90% of cooling airflow for HP-CFMT selection.
(2.) Terminals EAC-1 and EAC-2 are energized with 115v
when the BLWM is operating.
(3.) When the thermostat is satisfied, the furnace BLWM
continues operating at the same heat pump heating
airflow for an additional 90 sec.
d. Two-Speed Heat Pump Heating
(1.) The thermostat closes the R to Y1-and-G circuits for
low heat and operates the furnace BLWM at heat
pump low-heat airflow (may not be identical to
low-cooling airflow, depending on HP selection at
airflow selector). Closing the R-Y/Y2, Y1 and G
circuits to the furnace provides BLWM heat pump
high-heat airflow.
NOTE: The furnace control CPU controls BLWM airflow by
sensing G and Y1 for heat pump low-heating airflow, and G, Y1,
and Y/Y2 for heat pump high-heating airflow (105% of single-
speed heating airflow).
(2.) Terminals EAC-1 and EAC-2 are energized with 115v
when the BLWM is operating at either heating air-
flow.
(3.) When the thermostat is satisfied, the furnace BLWM
continues operating at the same heating airflow for an
additional 90 sec.
(4.) Opening only the R-Y/Y2 circuit switches the BLWM
to heat pump low-heating airflow.
6. Defrost
a. When the furnace control R to W/W1-and-Y/Y2 circuits
are closed, the furnace control CPU continues BLWM
operation at the heat pump heating airflow until the end of
the prepurge period, then shuts off BLWM until the end of
the HSI ignitor-on period (22 sec).
b. When installed with a heat pump, the furnace control CPU
automatically holds the blower-off time to 22 sec during
the HSI ignitor-on period. After 17 sec of the HSI
ignitor-on period, a trial-for-ignition sequence occurs as
described above for gas heating. After flame is proven and
without a blower-on delay, the BLWM then operates at
high-gas-heat airflow during defrost. For both single-speed
and 2-speed heat pumps, defrost mode is in high-gas heat
only.
c. When furnace control R-W/W1 circuit is opened, the
furnace control CPU begins the normal inducer post-purge
period and the BLWM continues operating for the blower-
off delay period. If the R-G circuit remains closed, the
BLWM reverts to continuous-blower operation.

SET-UP PROCEDURES

The ICM2+ blower motor operating mode selections are made on
the airflow selector control with color-coded jumper wires. The
factory jumper settings have large bold circles marked around the
pins. (See Fig. 16.)
NOTE: The ICM2+ furnaces are not approved for twinning.
1. Gas Heating
a. The VIOLET wire is factory connected to 1 of 4 pins: A, B,
C, or D on airflow selector. The factory pin selection can be
checked by noting PIN marking in the lower right-hand
corner of furnace rating plate.
b. The gas heating air temperature rise is selected on airflow
selector (See Fig. 15.) with RED and VIOLET jumper
wires. The selections are MID, HI, and MED-HI. MID
gives mid point of temperature rise range marked on rating
plate. HI gives high end of temperature rise range. MID-HI
gives temperature rise about halfway between MID and HI.
Select the rise by moving WHITE connectors on RED and
VIOLET jumper wires to desired pin positions. These
settings select the rise for high and low stages. See Table 8
for air temperature rise.
A
D7
D6
R2
R1
BLU
HI
400
M-HI
M-LO
350
315
LO
COOL COOL
CFM
S PER
I TON
Z
E YEL BLU
→
Fig. 15—Airflow Selector Control
2. Cooling and Heat Pump Heating
a. The cooling and heat pump selections can be determined
from Tables 9 and 10. The selections are made by moving
the WHITE connector on appropriately colored jumper
wire to desired pin position.
NOTE: Power must be cycled off and then on for the cool size
selection to take effect. Power need not be cycled off and on for the
CFM/TON to take effect.
b. The YELLOW COOL SIZE jumper is used to select
airflow to match the needed tons for the cooling or heat
pump system. The BLUE CFM/TON jumper is used to
select a slight adjustment to the airflow. The traditional
CFM per ton is 400 for cooling and heat pump airflow. 350
14
B C D
P12
D1
D2
D10
D3
Q1
D4
R3
D5
D11
K1
D8
D9
RED GRN
AC
HI
MID
HP
M-HI
MED
EFFY
HP
LO
CMFT
HI
AC GAS CONTINUOUS FAN
HEAT CFM
HP TEMP
RISE
ORN RED
GRN
A96061