Cooling; Humidi- - Mizer System (Optional); Economizer (Optional) - Carrier WeatherExpert 48LC Installation Instructions Manual

ERROR#
1 Check Smoke Detector/PMR/AUX
2 Check HPS/LPS/COFS
3 Call for Y3 with no call for Y1. Check Y1 wiring.
4 Call for Y3 with no call for Y1/Y2. Check Y1 wiring.
5 Call for Y2 with no call for Y1. Check Y1 wiring.
6 Call for W2 with no call for W1. Check W1 wiring.
7 Call for heat (W1/W2) and cooling (Y1/Y2/Y3). Check thermostat wiring.
8 Call for heat (W1/W2) with no IFM. Check G wiring.
9 Call for cooling (Y1/Y2/Y3) with no G. Check G wiring
Call for heat (W1/W2) and cooling (Y1/Y2/Y3) with no G.
10
Check thermostat and G wiring.
11 Check ISC Board and the thermostat wiring
Call for Economizer Y1 Feedback (ECON) from economizer with no call
12
for Y1 from thermostat. Check thermostat and economizer wiring.
13 Check ISC Board and the thermostat wiring
14 Check ISC Board and the thermostat wiring
15 Check ISC Board and the thermostat wiring
NOTES: 1. Green LED Blinking at 1Hz indicates normal operation.
2. Solid red LED indicates an error exists, see above LED configuration.
Cooling —
In the Cooling Mode, the small and large compressors will
be sequenced to maintain the thermostat temperature
setpoint. The chart below shows the cooling operation
based on the following conditions.
INPUT
Compressor
Thermostat
C1
First Stage Cooling
On
(Y1)
Second Stage Cooling
Off
(Y2)
Third Stage Cooling
On
(Y3)
The outdoor fan and VFD controlled indoor- - fan will
operate at low, medium and high speed. The indoor- - fan
speed (rpm) is factory set by the CFM and static pressure
requirements for the unit installed.
Humidi- - MiZer R System (Optional) —
In the Dehumidification Mode, both compressors will run
and Indoor airflow will be rise to High Speed.
At subcooler reheating mode (reheat- - 1), during part load
conditions when the room temperature and humidity are
above the set point, the unit initiates the sub- - cooling
mode of operation;
dehumidification. RDV (Reheat Discharge Valve) and
TWV (Three Way Valve) close; Indoor and Outdoor
airflow will rise until reaching 100% of Speed.
At hot- - gas- - bypass reheating mode (reheat- - 2), when there
is a call for dehumidification without a call for cooling, a
portion of the hot gas from the compressor bypasses the
condenser coil when RDV opens and hot gas is fed into
the liquid line, TWV closes in this mode and the system
provides mainly latent cooling. Indoor airflow will rise
Table 6 – Status Code Descriptions for ISC Board LEDs
ERROR NAME
OUTPUT
Indoor Outdoor
Compressor
Fan Fan
C2
Speed Speed
Low
Off Low
(700 rpm)
Medium
On Medium
(800 rpm)
High
On High
(1000 rpm)
a call for

cooling

LED01
RED
RED
RED
RED
RED
RED
RED
RED
until reaching 100% of Speed, Outdoor airflow will run at
High speed as long as outdoor temperature is above 80_F
(26.7_C); when operating in this mode below 80_F
(26.7_C) OAT, the system outdoor fan will operate as
shown in the table below based on Size:
LC Size RPM
07 250
Economizer (Optional) —
When the economizer is in Free Cooling Mode and a
demand for cooling exists (Y1 on the thermostat), the
economizer will modulate the outdoor- - air damper to
provide a 50_F (10_C) to 55_F (13_C) mixed- - air
temperature into the zone and run the indoor- - fan at high
speed. As mixed- - air temperature fluctuates above 55_F
(13_C) or below 50_F (10_C) dampers will be modulated
(open or close) to bring the mixed- - air temperature back
within control. Upon more call for cooling (Y2 on the
thermostat), the outdoor- - air damper will maintain its
current position, compressor C1 will run and the
outdoor- - fan will run at low speed. If there is further
demand for cooling, the outdoor- - air damper will maintain
its current position, only compressor C2 will run and the
outdoor- - fan will run at medium speed. The VFD
controlled indoor- - fan will operate at high speed
regardless of the cooling demand.
and
If the increase in cooling capacity causes the mixed- - air
temperature to drop below 45_F (7_C), the outdoor- - air
damper will return to the minimum position. If the
mixed- - air temperature continues to fall, the outdoor- - air
damper will close. Control returns to normal once the
mixed- - air temperature rises above 48_F (9_C). The
power exhaust fans will be energized and de- - energized, if
installed, as the outdoor- - air damper opens and closes.
In field- - installed accessory CO
the Economizer, a demand controlled ventilation strategy
31
LED INDICATION
LED02 LED03 LED04
RED
RED
RED
RED
RED RED
RED RED
Blinking
RED RED
Green
RED RED
LED
(Note 1)
RED
RED
RED
RED
Number of Fans On Number of Fans Off
2 0
sensors are connected to
2
LED05
RED
RED
RED
RED
RED
RED
RED
RED