24VNA6 / 25VNA4: Service Manual
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17
Bluetooth Module
The Bluetooth module used with Carrier Service Tech App can collect
recent fault codes, monitor system operation, and update software. The
Bluetooth module is connected to the PCM via a wire harness mounted
on the bottom horizontal section of control panel and is centered over the
plastic insert to maximize transmission range of module. See appropriate
fault code description for Bluetooth Module related faults. If
unsuccessful with pairing while fault is not active, see service app for
troubleshooting.
DIAGNOSTIC CODES AND TROUBLESHOOTING
Code 13-53 System Control Upgrade Strongly Recommended
Code 13-82 System Control Upgrade Recommended
Code 13-53 indicates that the system control is sufficiently out of date
that the equipment will operate and that it is likely that the homeowner
will take notice of sub-optimal behavior.
Code 13-82 indicates that the system control is out of date and should be
upgraded to take full advantage of the features and functionality of the
equipment system.
To correct codes 13-53 or 13-82, upgrade the system control to the latest
version available.
Code 14-94 Line Voltage Low
Low line voltage may result in increased electronic component
temperatures and shorten the life of VFD. Since control voltage is based
on line voltage, solenoids and relays may not pull in and hold correctly
as well. "Line Voltage Low" fault is set when incoming line voltage
drops below 180V AC RMS at any time, or when line voltage drops
below 185V AC RMS for more than 5 seconds. Once line voltage
increases above 187V, the fault will clear. While fault is active unit will
not operate or will shut down if already running. This fault does not
escalate to a malfunction.
This measurement is taken at the secondary side of 24V transformer and
a scaler value applied at the factory to correct for transformer variation.
Technician should first measure incoming line voltage at terminal block.
Second, check tightness of all line voltage connections. Loose
connections can cause excessive voltage drop and trigger this fault. If all
connections are tight and line voltage is still low, additional steps
involving the local power utility or addition of external power
conditioner may be required.
Code 15-94 Line Voltage High
High line voltage may result in increased stress on electronic
components and shorten the life of VFD. "Line Voltage High" fault is set
when incoming line voltage rises above 285V AC RMS at any time, or
when line voltage rises above 280V AC RMS for more than 5 seconds.
Once line voltage drops below these thresholds the fault will clear.
While fault is active unit will not operate or will shut down if already
running. This fault does not escalate to a malfunction.
This measurement is taken at the secondary side of 24V transformer and
a scaler value applied at the factory to correct for transformer variation.
Technician should first measure incoming line voltage at terminal block
using VOM. If voltage reading is below 285 VAC RMS, perform voltage
calibration steps using service app. If VOM measured voltage is above
280VAC RMS, additional steps involving the local power utility or
addition of external power conditioner may be required.
Code 17-06 Lost BTM Communication
The Bluetooth module used with Carrier Service Tech App can collect
recent fault codes, monitor system operation, and update software. The
Bluetooth module is connected to PCM via wire harness and is mounted
on the bottom horizontal section of control panel and is centered over the
plastic insert to maximize transmission range of module. After unit
power up, the Bluetooth module will send periodic messages to PCM
which confirm the status of module. If 2 consecutive minutes of
messages are missing, code 17-06 will become active. Code 17-06 will
clear when a single good message is received by PCM. If this fault is
active, inspect PCM to Bluetooth module harness and ensure both ends
are fully seated on board header. Also inspect and repair any wire
damage on harness. If no green or red led is present on the Bluetooth
module, disconnect harness at the Bluetooth module and check for 18-30
VAC between pins 1 and 3 at the Bluetooth module connector end of
harness. If voltage is present and code is active, replace Bluetooth
module. An active code 17-06 will not affect system operation in any
way except the service tool app will not connect to unit. If code is
cleared and service app is not able to connect to Bluetooth module,
follow troubleshooting steps in service app.
Code 18-11 Indoor Coil Freeze Protection
Code 18-11 indicates that the equipment is reducing compressor speed
compared to the requested capacity demand in an effort to prevent ice
accumulation on the indoor coil. The PCM monitors the saturated
suction temperature at the compressor, and when the saturation
temperature approaches 32°F, the compressor speed is reduced until the
saturated suction temperature is above 32°F. If the compressor speed
reduction is not able to achieve a saturated suction temperature above
32°F then it will continue to operate until either demand is removed or a
32-15 occurs.
Code 18-11 has been activated in PCM software versions 5.0 and above.
This fault is not active in PCM software versions less than 5.0
Code 18-11 can be caused by insufficient airflow across the indoor coil
due to a dirty filter or restrictive ductwork. Code 18-11 can also be
caused by insufficient refrigerant charge in the system. Check the indoor
equipment for excessive static air pressure and check refrigerant charge
levels to correct this fault.
Code 24-58 5V PCM Power Out of Range Lockout
The PCM supplies 5V DC to VFD through the communication harness
to power low voltage IC's (pin 4 of 6 pin wire harness). If this voltage is
interrupted the VFD will cease to communicate with PCM. The PCM
will continue to operate for a short period of time in case this
interruption is intermittent, but if the voltage is not restored the system
will shut down and declare code 24-58. The fault will clear once 5V DC
is restored to VFD via PCM communication harness. The 5VDC on
communication harness is shared with 5VDC powering pressure
transducers.
When code 24-58 is active disconnect PCM to VFD communication
harness and measure voltage between pin 3 (GND) and pin 4 (+5V DC)
at the VFD connection end. If voltage is present, reconnect harness,
power cycle, and check if fault is still present. If so, VFD will require
replacement. If voltage is not present at VFD end of harness, check for
voltage at the PCM header. If voltage is not present there, Disconnect all
other sensors from PCM until fault is cleared. Whichever sensor is
disconnected that makes fault disappear should be inspected for damage,
likely a short exists in the harness. Once all sensors are disconnected and
fault is present, confirm 5VDC is not present on PCM board, if not then
replace PCM.
Code 25-22 Model Plug Missing
Code 25-62 Model Plug Missing Lockout
The Model Plug Missing Fault and Malfunction indicate that a model
plug is not presently installed on the PCM or was not present when
power was applied to the equipment. If a valid model plug has
previously been installed, the PCM will have the most recently installed
model plug value stored in memory.
Code 25-22 indicates that a valid model plug value is present in memory,
but a model plug is not currently installed. If a Code 25-22 is active, the
equipment will operate properly provided that the model plug value in
memory corresponds to the equipment model. To clear Code 25-22,
remove power from the equipment, install the model plug corresponding
to the equipment model, and reapply power to the equipment.
Code 25-62 indicates that a valid model plug was not present when the
equipment was powered up, and there is no valid model plug value
stored in PCM memory. If a Code 25-62 is active, the equipment will
not operate. The PCM will not acknowledge a new model plug
installation while power is applied to the equipment. To clear Code
25-62, remove power from the equipment, install the model plug
corresponding to the equipment model, and reapply power to the
equipment. Code 25-62 can only be cleared by having a valid model
plug installed when power is applied to the equipment.
