Carrier 50HX Guide, Installation, Start-Up, And Operating Instructions Manual, Page: 24 / 36

compressor starts. Energizing the contactor closes the normally-
open set of contacts supplying power to both the compressor and
outdoor (condenser) fan motor (OFM). Energizing the IFR closes
the normally-open set of contacts providing power to the IFM. On
the loss of the call for cooling, 24 v is removed from both the Y
and G terminals of the thermostat (providing the FAN switch is in
the AUTO. position), deenergizing both the contactor and IFR and
opening both the contacts supplying power to compressor/OFM
and IFM.
ECM Blower Motor Units (048–060)
Indoor Fan - With the fan switch in the ON position, 24-v is
supplied to the ECM motor through the ’’G’’ terminal on the
thermostat. This voltage provides continuous power to the indoor
(evaporator) fan motor (IFM). If the fan switch is moved back to
the AUTO position and there is not a call for heating or cooling,
24-v is removed from the ’’G’’ terminal and the indoor fan
remains energized for the delay timing. When the fan switch is in
AUTO, the fan cycles with either the call for heating or cooling.
Cooling- On a call for cooling, 24 v is supplied to the compressor
contactor (C) and IFM simultaneously through the ’’Y’’ and ’’G’’
terminals of the thermostat. Energizing the contactor closes the
normally open set of contacts supplying power to both the
compressor and outdoor (condenser) fan motor (OFM). On the loss
of the call for cooling, 24 v is removed from the ’’Y’’ and ’’G’’
Table 5—Terminal Configuration
TERMINAL 1 2 3 4
Available
Airflow (CFM)
1365 1470 1680 1840
Fig. 29—Easy Select Interface Board for Units 048-060 with ECM Blower Motor
C95024
AUX HEAT
RANGE
VIO
1 2 3 4
BLU
1 2 3 4
AC/HP SIZE
BRN
AC HPC H P
TYPE
BLK
LO MED H I
AC/HP CFM ADJUST
GR Y
AC/HP TIME DELAY
1 2 3 4
RED JW1 JW2
D4
D5
P1
1
W3 W2
E
/W
1
G
Y1 Y /Y2
O C R
L
1
P2
JW3
Y1
G
W2
Y/Y2
JW 4 JW 5
R1
R2
R3
IFO
O
SEC-1
SEC-2
L
D3
D1
D2
F1
5 AMP FUSE
5
Table 6—CFM Adjust (Percent of CFM)
MODE FAN ONLY COOLING HEATING
LO-Adjust
–15 –10 –10
HI-Adjust
15 10 10
Table 7—ECM Board Pin Selection
OPTION DESCRIPTION
30-Sec On/60-Sec Off Delay
Profile (Terminal 1)
Used when it is desirable to allow system coils time to heat
up or cool down prior to airflow
No Delay Option
(Terminal 2)
Used for servicing or when other components are used to
perform the delay function
30-Sec Off Delay
(Terminal 3)
Preset factory setting for 50HX units
45-Sec Off Delay
(Terminal 4)
Enhances system efficiency
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