Bosch Climate 5000 Series Service Manual page 18

1 8 | Bosch Climate 5000 Series Ductless Air Conditioner / Heat Pump Multi Zone Outdoor Units
7.4.2 Defrost Control
Conditions for Defrost Mode:
After the compressor starts and enters normal operation, mark the minimum value
of T3 from the 10th to 15th minute as T30.
If any one of the following conditions is satis ed, the unit enters defrost mode:
1. If the compressor's cumulative running time reaches 29 minutes and T3 <
TCDI1 and T3 + T30SUBT3ONE T30.
2. If the compressor cumulative running time reaches 35 minutes and T3 <
TCDI2 and T3 + T30SUBT3TWO T30.
3. If the compressor cumulative running time reaches 40 minutes and T3 <
-24°C for 3 minutes.
4. If the compressor cumulative running time reaches 120 minutes and T3 <
-15°C.
Defrost Stop Conditions
If any one of the following conditions is satis ed, defrost mode ends and the unit
returns to normal heating mode:
T3 rises above than TCDE1°C.
T3 remains at TCDE2°C or above for 80 seconds.
The machine runs for 10 consecutive minutes in defrost mode.
Defrosting Action:
4-way valve defros ng
off
compressor
Max 10 minutes
frequency
Cool-F9
10S 30S
Indoor fan
off
Outdoor fan
off
EXV open
480P
Figure 19
Condition of ending defrosting:
If any one of following items is satis ed, defrost mode will stop and the machine will
return to normal heating mode.
T3 > TempQuitDefrost_ADD °C;.
Defrost mode runs for 10 minutes
TempQuitDefrost_ADD is slightly different depending on out door
models, but is about 12 C (54 F).
Data subject to change
Defros ng over
on
frequency
Compressor stops
TimeA
10S
An -cold control
480P for 240s
7.4.3 Outdoor Fan Control
7.4.3.1 Cooling Mode
Under normal operating conditions, the system chooses the running fan speed
according to the ambient temperature:
Figure 20
Low ambient cooling mode logic:
When T4 < 15 °C (59 °F) and T3 < 30 °C (86 °F), the unit enters into low
ambient cooling mode. The outdoor fan chooses a speed according to T3.
When T3 38 °C (100.4 °F) or when T4 20 °C (68 °F), the outdoor fan
chooses a speed according to T4 again.
Exit low ambient cooling
mode
38
for 1 minute
27
Low
off
Figure 21
Service Manual
,
run with high fan
30
23
08.2020 | Bosch Thermotechnology Corp.