Carrier 40VMZ Installation And Maintenance Instructions Manual page 20

ERROR DESCRIPTION
Heating / Cooling Mode Conflict
dd
System is in heating mode, and
cooling signal is received from a
unit in the system
Communication Error Between
E1
Indoor and Outdoor Unit
E2, E3, E4, E5 Check Temperature Sensor
E6 DC Fan Motor
E7 EEPROM Error (Data Storage)
Communication Error Between
E9
Indoor Unit and Controller
Eb EEV Error
Ed Outdoor Unit Error
EE Condensate Error
No Address When Power ON for
FE
first time
UU MDC Auto System-Check Mode
LEGEND
EEV - Electronic Expansion Valve
EEPROM - Electronically Erasable Programmable Read-only Memory
MDC - Multiport Distribution Controller
PC - Process Controller
NOTE: When the Reheat Unit has finished the troubleshooting, the corresponding Outside Air Unit has to turn off for 1 minute, then
restart again, in case the fan of the Reheat Unit cannot start normally
Table 6 —Troubleshooting
POSSIBLE CAUSES
System is in cooling or fan only mode, and
heating signal is received from a unit on the
system
System is in heating mode and cooling
signal is received from a unit in the system
Signal wires are short-circuited or
disconnected
Signal wire close to electromagnetic source
PC board fault
Loose connection at port on PC board
Sensor is short-circuited
PC board fault
Operating beyond limits
DC motor fault
PC board fault
Chip or PC board fault
Signal wires are short-circuited or
disconnected
Signal wires close to electromagnetic source
PC board fault
EEV wires are short-circuited or
disconnected
EEV Stop
PC board fault
Outdoor unit fault
Loose connection or disconnected
Water level float is stuck
Trap slope is too steep
Drain pipe is too long
Drain pump faulty
Indoor unit without address
MDC fault
20
POSSIBLE SOLUTIONS
All units should be in cooling mode for
system to stay in cooling mode
All units should be in heating mode
Check or reconnect signal wire
Distance signal wires from
electromagnetic source
Replace PC board
Tighten the connection at port on PC
board.
Using multi-meter, measure
resistance of sensor; if resistance is
≤100 ohms, change the sensor
Replace PC board
Check and correct external static
pressure on the unit
Replace DC motor
Replace PC board
Replace PC board
Check or reconnect signal wires
Distance signal wires from
electromagnetic source
Replace PC board
Replace EEV wires
Replace EEV
Replace PC board
Refer to outdoor unit troubleshooting
guide
Tighten the connection or reconnect
at port on PC board
Inspect the slope
Adjust the trap slope
Adjust the length of drain pipe
Replace the drain pump
Run automatic addressing option at
the outdoor unit
Use remote wireless or wired
controller to re-address indoor unit
Refer to MDC troubleshooting guide