Daikin RZQ100B8V3B Service Manual page 139

ESIE05-03
3.3.10 Pressure Difference Control
Outline To ensure the compression ratio (pressure difference between high and low pressure) at low outdoor
temperature conditions in cooling mode and high outdoor temperature conditions in heating mode, the
outdoor fan and target compressor frequency may be varied.
Cooling In cooling low ambient conditions, the outdoor fan speed and compressor frequency will be adapted
to secure the differential pressure between high and low pressure.
Fan control in
cooling
&
&
Parameters
T°C
Part 2 – Functional Description
HP < 19 bar
TA < 25°C
&
∆
P < 9.5bar
OR
Compression ratio < 2.1
Condition A
Condition A
90 seconds have passed
HP < 16 bar
∆
Condition A
P < 8bar
OR
Compression ratio < 1.8
Condition A
Condition A
Condition A
Condition A
Condition A
T < (T - 15) °C
Fin
90 seconds have passed Condition A
HP < 16 bar
∆
P < 8bar
OR
Compression ratio < 1.8
RZQ71B8V3B
79°C
Outdoor Unit Functional Concept
Normal control
Upper limit (step 8)
HP > 35 bar (RZQ100~140)
HP > 30 bar (RZQ71)
TA > 27°C
OR
&
&
Upper limit (step 8)
Condition B
Upper limit (step 7)
Condition B
Upper limit (step 6)
Condition B
Upper limit (step 5)
Condition B
Upper limit (step4)
Condition B
Upper limit (step 3)
Condition B
Upper limit (step 2)
Condition B
Upper limit (step 1)
Condition B
Upper limit (step 0)
= Outdoor fan OFF
RZQ100~125B8V3B
71°C
∆
P > 15bar
Compression ratio > 3.2
Outdoor fan upper limit : step 8
∆
P > 11bar
Compression ratio > 2.4
Condition B
90 seconds have passed
HP > 20bar (RZQ71)
HP > 17bar (RZQ100~140)
&
OR
∆
P > 10bar
&
Compression
ratio >2.2
HP > 18 bar
Tfin > T °C
∆
P > 9bar
OR
Compression
&
ratio > 2.0
RZQ100~140B7W1B
68°C
2–55
1
2
3
4
5