Carrier Infinity 50XT-A Installation Instructions Manual page 18

OPERATION
Standby – no call for unit opera-
tion
Emergency Mode
Low Stage Cool/Heat Operation
High Stage Cool/Heat Opera-
tion
COOLING AND HEATING OPERATION
With a call for first stage cooling, the outdoor fan, reversing valve,
and low stage compressor are energized. If low- -stage cannot
satisfy cooling demand, high- -stage cooling is energized by the UI.
After second stage is satisfied, the unit returns to low- -stage
operation until first stage is satisfied or until second stage is
required again. When both first stage and second stage cooling are
satisfied, the compressor will shut off. The reversing valve will
remain energized until the control board power is removed or a call
for heating in initiated. With a call for heating, the outdoor fan and
compressor are energized. The compressor will operate in high or
low stage operation, as needed to meet the heating demand. When
Table 2 – Heat Pump/Air Conditioner Board Status Codes
AMBER
LED
FAULT
FLASH
CODE
On solid,
None
no flash
Rapid, con-
Standard Ther-
tinuous
mostat Control
flashing
None 1, pause
None 2, pause
System Commu- 16
nications Failure
Invalid Model
25
Plug
High--- Pressure
31
Switch Open
Low--- Pressure
32
Switch Open
Control Fault 45
Brown Out
46
(230 v)
No 230v at Unit 47
Outdoor Air
Temp Sensor 53
Fault
Outdoor Coil
55
Sensor Fault
Thermistors Out
56
of Range
Low Stage Ther-
71
mal Cutout
High Stage Ther-
72
mal Cutout
Contactor
73
Shorted
No 230V at
74
Compressor
Low Stage Ther-
81
mal Lockout
High Stage Ther-
82
mal Lockout
Low--- Pressure
83
Lockout
High--- Pressure
84
Lockout
POSSIBLE CAUSE AND ACTION
Normal operation.
Unit being controlled by standard thermostat inputs instead of Infin-
ity Control. Only high stage operation is available. This operating
mode should be used in emergency situations only.
Normal operation.
Normal operation.
Communication with UI lost. Check wiring to UI, indoor and outdoor
units.
Control does not detect a model plug or detects an invalid model
plug. Unit will not operate without correct model plug.
High--- pressure switch trip. Check refrigerant charge, outdoor fan
operation and coils for airflow restrictions.
Low--- pressure switch trip. Check refrigerant charge and indoor air
flow.
Outdoor unit control board has failed. Control board needs to be
replaced.
Line voltage < 187v for at least 4 seconds. Compressor and fan
operation not allowed until voltage>190v. Verify line voltage.
There is no 230v at the contactor when indoor unit is powered and
cooling/heating demand exists. Verify the disconnect is closed and
230v wiring is connected to the unit.
Outdoor air sensor not reading or out of range. Ohm out sensor
and check wiring.
Coil sensor not reading or out of range. Ohm out sensor and check
wiring.
Improper relationship between coil sensor and outdoor air sensor.
Ohm out sensors and check wiring.
Compressor voltage sensed, then disappears while cooling or heat-
ing demand exists. Possible causes are internal compressor over-
load trip or start relay not releasing (if installed).
Compressor voltage sensed, then disappears while cooling or heat-
ing demand exists. Possible causes are internal compressor over-
load trip or start relay not releasing (if installed).
Compressor voltage sensed when no demand for compressor op-
eration exists. Contactor may be stuck closed or there is a wiring
error.
Compressor voltage not sensed when compressor should be start-
ing. Contactor may be stuck open or there is a wiring error.
Thermal cutout occurs in three consecutive low/ high stage cycles.
Low stage locked out for 4 hours or until 24v power recycled.
Thermal cutout occurs in three consecutive high/low stage cycles.
High stage locked out for 4 hours or until 24v power recycled.
Low--- pressure switch trip has occurred during 3 consecutive
cycles. Unit operation locked out for 4 hours or until 24v power
recycled.
High--- pressure switch trip has occurred during 3 consecutive
cycles. Unit operation locked out for 4 hours or until 24v power
recycled.
the heating demand is satisfied, the compressor and fan will shut
off. The reversing valve is de- -energized in the heating mode.
NOTE: When two- -stage unit is operating at low- -stage, system
vapor (suction) pressure will be higher than a standard single- -stage
system or high- -stage operation.
NOTE: Outdoor fan motor will continue to operate for one
minute after compressor shuts off, when outdoor ambient is greater
than or equal to 100°F (38°C).
UTILITY INTERFACE WITH INFINITY CONTROL
The utility curtailment relay should be connected to factory
supplied pigtails (PINK, connected to R, VIOLET connected to Y2
on the control board) located in the low voltage splice box (See
18