Bosch Climate 5000 Series Service Manual page 55

Remark:

Use a multimeter to test the DC voltage between 2 port and 3 port of
outdoor unit. The red pin of multimeter connects with 2 port while the
black pin is for 3 port.

When AC is normal running, the voltage will move alternately between
-25VDC to 25VDC.

If the outdoor unit has malfunctioned, the voltage will move alternately
with positive value.

While if the indoor unit has malfunction, the voltage will be a certain
value.
Figure 70
Bosch Climate 5000 Series Ducted Type (Medium & High Static) Air Conditioner / Heat Pump (11.2022)
Remark:

Use a multimeter to test the resistance of the transformer which does not
connect with capacitor.

The normal value should be around zero ohms. Otherwise, the reactor
must have malfunctioned and may need to be replaced.
Figure 71
Service Manual
| 55