Frost Prevention Control During Cooling Or Dehumidifying; Air Capacity Control - Mitsubishi Heavy Industries SRK20ZSPR-S Technical Manual

(ii) Contents of operation
1)

Air capacity control

Item
Upper limit of compressor's command speed
Note (1) Ranges A and B are as shown below.
Range A
Cancel
63
2) When this control has continued for more than 30 minutes continuously, the following wind direction control is per-
formed.
a) When the vertical wind direction is set at other than the vertical swing, the flaps change to the horizontal position.
b) When the horizontal wind direction is set at other than the horizontal swing, the louver changes to the vertical po-
sition.
(iii) Reset condition: When any of followings is satisfied.
1) Compressor's command speed is less than 28 rps.
2) Detected value of humidity is less than 63%.
(b) Frost prevention control
(i) Operating conditions
1)
2)
(ii) Detail of anti-frost operation
Indoor heat exchanger
Item
Lower limit of compressor command speed
Indoor fan
Outdoor fan
4-way valve
(iii) Reset conditions:
1)
2)
(c) Cooling overload protective control
(i) Operating conditions:
Item
Outdoor air temperature
Lower limit speed
(ii) Detail of operation
Range B
68 78
Humidity (%)
temperature 5°C or lower
22 rps (model SRK63 : 25rps)
more, with the compressor running, the lower limit
Model
SRK63, 71, 80ZM-S
Model
SRK63ZSPR-S
(1)
Range A: As per following table, Range B: 40 rps
● Condition for range A
Compressor's command speed is controlled according to the indoor
unit heat exchanger temperature (Th2) and the indoor unit room
temperature (Th1).
Condition
・ Decreases the compressor's target max speed
・ If the condition is met still 20 seconds later,
Th2 ≦ Th1 ‒ 10
Th1 ‒ 10 ＜ Th2 ≦ Th1 ‒ 6
Th2 ‒ 6 ＜ Th1
2.5°C or lower
2.5–5ºC
5–8ºC
86
- -
'17 • SRK-T-206
SRK71ZSPR-S SRK80ZSPR-S
Compressor's command speed
by 4 rps.
the speed is decreased further by 4 rps. This
process is repeated further so far as the
condition is met. (Lower limit is 30 rps.)
Compressor's target max. speed or changed
value of the same is maintained.
Changed compressor's target max. speed is
increased at a rate of 1 rps/20 seconds.
'09•SRK-DB-087D
Compressor
command
speed
Lower
limit
speed
0 rps
2.5
Indoor heat exchanger
temperature (ºC)
ON1
OFF
40 41 46
Outdoor air temperature (°C )
5 8
ON2
47