Checking the essential components of the external unit, type
OS303H, OS304H, OS305H
Power supply
The mains voltage must be between
198 and 264 V~.
External fan
Start test mode (see page 29).
Check the voltage at the fan motor
supply cables:
Across the red and black core: 310 V
–
± 20 V
Across the orange and black core:
15 V
–
± 1 V
Across the yellow and black core: 2 -
6 V
–
Compressor
The compressor operates with a
brush-less DC permanent magnet
motor.
The three winding resistances must
be identical and be lower than
0.5 Ohm.
Reversing valve
In heating mode, the voltage at the
reversing valve must be 220 V~.
Electronic expansion valve
The voltage at the stepper motor of
the valve must be 12 V
–
.
The EEV must be switched ON simul-
taneously with the external unit. It will
generate noise and vibrations.
Checking the essential components of the external unit, type
OS307H
Power supply
The mains voltage must be between
198 and 264 V~.
Diagnosis
(cont.)
26
Troubleshooting
5692
687
GB
Summary of Contents for Vitoclima 300-S
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