Mitsubishi Heavy Industries FDU Series Service Manual page 44

(7) Cooling low outdoor temperature protective control
(a) Operating conditions
When the outdoor air temperature (TH2) is CºC or lower continues for 20 seconds while the compressor speed is
other than 0 rps.
(b) Detail of operation
(i) The lower limit of the compressor speed is set to 45 (35) <20> rps and even if the speed becomes lower than 45 (35)
<20> rps, the speed is kept to 45 (35) <20> rps. However, when the thermostat OFF, the speed is reduced to 0 rps.
(ii) The upper limit of the compressor speed is set to 75 <120> rps and even if the calculated result becomes higher
than that after fuzzy calculation, the speed is kept to 75 <120> rps.
Notes (1) Values in ( ) are for outdoor air temperature is C or D.
(2) Values in < > are for outdoor air temperature is E or F.
Upper limit 75 rps
ON
Lower limit 45 rps
A B
Outdoor air temperature (°C)
(iii) Reset conditions
When either of the following condition is satisfied.
1) The outdoor air temperature (TH2) is F ºC or higher.
2) The compressor speed is 0 rps.
(8) Heating high pressure control
(a) Starting condition
When the indoor heat exchanger temperature (Thi-R1, R2) has risen to a specified temperature while the compressor
is turned on.
(b) Compressor speed is controlled according to the zones of indoor heat exchanger temperature as shown by the
following table.
Protection control speed (NP)
Sampling time (s)
Model FDC90, 100VNP-W
Thi-R
NP
<
10 NP < 90
=
<
90 NP < 120
=
<
120 NP
=
After lapse of 20 sec. or over
A
Outdoor heat exchanger temperature (°C)
C
2
ON
Upper limit 75 rps
Lower limit 35 rps
ON
Upper limit 120 rps
Lower limit 20 rps
C D E F
<
Thi-R < P1 P1 Thi-R < P2
=
Normal Retention
Normal 10
P1 P2
45 52
45 - 43 52 - 45 57 - 48
43 45
43
-
lower limit
(3)
speed 30 rps
B
B -C
A -B
● Values of A, B, C, D, E, F
Model FDC90, 100VNP-W
First time
OFF
< <
P2 Thi-R < P3 P3
= =
NP － 4rps NP － 8rps
10
Unit: °C
P3
57
48
-
0rps
'19 • PAC-SM-334
C
8 20
Outdoor air temperature (˚C)
A B C D
9 11 22 25
Thi-R
10
E F
26 28