Bosch Climate 5000 Series Service Manual page 19

Service Manual
Figure 22
7.4.3.2 Heating Mode
Under normal operating conditions, the system chooses a running fan speed
according to ambient temperature:
Figure 23
7.4.4 Electronic Expansion Valve (EXV) Control
1. EXV remains fully closed while the device is powering up. EXV then remains
on standby with 350 pulse open. It opens to the target angle after the
compressor starts.
2. EXV closes with -160 pulse when the compressor stops. Then it remains
on standby with 350 pulse open. It opens to the target angle after the
compressor starts.
3. The action priority for the EXVs is A-B-C-D-E.
4. The compressor and outdoor fan commence operation only after EXV
initializes.
Bosch Thermotechnology Corp. | 08.2020
Bosch Climate 5000 Series Ductless Air Conditioner / Heat Pump Multi Zone Outdoor Units | 19
7.4.4.1 Cooling Mode
The initial open angle of the EXV depends on the size of the indoor model. The
adjustment range is 100 pulse - 400 pulse.
When the unit has been running for 3 minutes, the outdoor receives indoor units'
capacity demand and T2B information and then calculates their average. After
comparing each indoor's T2B with the average, the outdoor gives the following
modi cation commands:
If T2B > average, the relevant valve needs to open 16P more
If T2B = average, the relevant valve's open range remains as is
If T2B < average, the relevant valve needs to close 16P more
This modi cation is carried out every 2 minutes.
7.4.4.2 Heating Mode
The initial open angle of the EXV depends on the size of the indoor model. The
adjustment range is 150 pulse - 350 pulse.
When the unit has been running for 3 minutes, the outdoor unit receives the indoor
units capacity demand and T2 information and then calculates their average.
After comparing each indoor unit's T2 with the average, the outdoor gives the
following modi cation commands:
If T2 > average +2, the relevant valve needs to close 16P more
If average+2 T2 average -2, relevant valve's open range remains as is
If T2 < average -2, the relevant valve needs to open 16P more
This modi cation is carried out every 2 minutes.
7.4.5 Four-Way Valve Control
In heating mode, the four-way valve is opened.
In defrost mode, the four-way valve operates according to the current defrosting
action.
In other modes, the four-way valve is closed.
When the unit is switched from heating to other modes, the four-way valve turns off
after the compressor has been off for 2 consecutive minutes.
Failure or protection (excluding discharge temperature protection and high/low
pressure protection) causes the four-way valve to immediately shut down.
Data subject to change