Nordic ATWC Series, Installation And Service Manual, Page: 66 / 106

PRELIMINARY: 24-Sep-2021 Page 66 002536MAN-00
OUTDOOR FAN TROUBLESHOOTING
Fault Possible Cause Verification Recommended Action
Outdoor fan not
operating or
operating
intermittently
Fan power connections Check for 230VAC across L1 and L2
of the outdoor unit. Proceed to next
step if voltage present.
If no voltage present, verify that
the connections are tight in both
the indoor and outdoor units.
Gently tug on each wire to verify
connection is good.
Repair any loose connections.
Faulty PWM signal on
GEN2 control board
Use manual mode of the PC APP to
set the outdoor fan to 50%. Using a
multi-meter set to VDC, measure
PWM1 to GND of the GEN2 control
board in the Indoor Unit. It should
be ~5VDC. Proceed to next step if
voltage present.
If signal is not present the control
board may be faulty. Try cycling
the power and retesting. If this
does not correct the problem re-
place the control board.
Fan PWM Signal connec-
tions
Use manual mode of PC APP to set
the outdoor fan to 50%. Using a
multi-meter set to VDC, measure
PWM to ground in the Outdoor Unit.
It should be ~5VDC. Proceed to next
step if voltage present.
If signal is not present, check
connections of PWM wire and
ground wire. Replace wiring if
connections are good.
Faulty fan motor All of the above checks have been
performed and everything is OK.
Replace fan motor.
OPERATION TROUBLESHOOTING - DEFROST & COOLING MODES
Fault Possible Cause Verification Recommended Action
Outdoor temper-
ature reading is
incorrect by a
large amount
Outdoor EEV is mechani-
cally faulty and causing
electromagnetic interfer-
ence
Verify EEV operation (EEV3 or
EEV4) - see EEV Troubleshooting
section
Replace outdoor EEV if faulty.
Faulty outdoor tempera-
ture sensor or outdoor
MODBUS board
Outdoor EEV verified to be good,
no loose connections in indoor to
outdoor control wiring
Replace outdoor temperature sen-
sor or outdoor MODBUS board.