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Service Manual
Bosch Climate 5000 Series Ductless Air Conditioner / Heat Pump Multi Zone Outdoor Units (01.2023)
For other models,
Control:
1. EXV remains fully closed while the device is powering up. EXV then remains
on standby with 350P open. It opens to the target angle after the compressor
starts.
2. EXV closes with -40P when the compressor stops. Then it remains on
standby with 350P 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.
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 100-400p.
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
modification commands:
f If T2B > average, the relevant valve needs to open 16P more
f If T2B = average, the relevant valve’s open range remains as is
f If T2B < average, the relevant valve needs to close 16P more
This modification 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 modification commands:
f If T2 > average +2, the relevant valve needs to close 16P more
f If average+2 ≥ T2 ≥ average -2, relevant valve’s open range remains as is
f If T2 < average -2, the relevant valve needs to open 16P more
This modification 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.
7.4.6 Outdoor Unit Digital Display
A digital display is featured on the outdoor PCB. The LED displays different codes in
the following situations:
f Standby: “- -.”
f Compressor operation: the running frequency.
f Defrosting mode: “dF” or alternative displays between running frequency
and “dF” (ach appears for 0.5s.)
f Forced cooling mode: the LED displays “FC” or alternative displays
between running frequency and “FC” (each appears for 0.5s).
f Compressor pre-heating: “PH” or alternative displays between running
frequency and “PH” (each appears for 0.5s.)
f Oil return process: “RO” or alternative displays between running frequency
and “RO” (each appears for 0.5s.)
f Low ambient cooling mode: “LC” or alternative displays between running
frequency and “LC” (each appears for 0.5s.)
f PFC module protection occurs three times within 15 minutes: “E6” or
alternates between displays of running frequency and “E6” (each appears
for 0.5s.)
f In protection or malfunction, the LED displays an error code or protection
code. “PH”, “RO”, “LC”, ”E6” are not suitable for 18-36K regular systems
and 18-27 hyper heat systems.
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