Mitsubishi Heavy Industries SRRM25ZF-S, Technical Manual, Page: 55 / 127

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53
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(4) Hot keep operation
If the hot keep operation is selected during the heating operation, the indoor fan is controlled based on the temperature of the
indoor unit heat exchanger (detected with Th
I
-R
1
)
Functional
components
Operation
Command speed
Indoor
unit fan
Compressor
Outdoor unit fan
Electronic
expansion valve
See preceding table
ON
According to command speed
According to outdoor unit speed
According to decision
speed
0
(All indoor units)
Hot Keep
OFF
According to stop mode
Hot Keep
Hot Keep
Hot Keep
0
(Thermostat off units)
ON
According to heating stop unit control
(Thermostat off units)
According to outdoor unit speed
According to mode switching
According to heating stop unit control
(Fan, stop, abnormal stop units)
0
(Fan, stop, abnormal stop units)
0
(All units)
ON
According to command speed
According to mode switching
OFF
OFF OFF
According to stop mode
Cooling
Thermostat OFF
(All indoor units) Thermostat OFF
(Some of indoor units)
Fan, stop, abnormal stop
(Some of indoor units)
Failure
(Outdoor unit)
Fixed
Automatic
(3) Operation of major functional components in heating mode
(5) Defrosting
(a) When the following conditions are met, the defrosting operation will start.
1) During normal operation
a) When 40 minutes has passed since the start of heating or 40 minutes after the last defrosting (based on cumulative
operation time of compressor).
b) When the outdoor heat exchanger sensor (Tho-R) temperature is –2
°
C or less for 3 continuous minutes after 37
minutes have passed.
c) Outdoor temperature sensor (Tho-A) – outdoor heat exchanger sensor (Tho-R) temperature >
= 0.44
×
outdoor tempera-
ture sensor (Tho-A) tempe A
°
C or more.
A = Outdoor temperature >
= – 2
°
C: 4, outdoor temperature < – 2
°
C: 6.
d) When the compressor is operating.
u
Or, during heating, defrosting will start when the decision speed counts zero (0) rps for 10 times or more and all
conditions in a), b) and d) above and when the outdoor air temperature is 3
°
C or less have been satisfied.
2) During defrosting acceleration
a) When 40 minutes has passed since the last defrosting (based on cumulative operation time of compressor).
b) When the compressor is operating.
u
Or, during heating, defrosting will start when the decision speed counts zero (0) rps for 10 times or more and all
conditions in a) and b) have been satisfied.
Note (1) Defrosting acceleration is when the finishing of the previous defrosting is according to the defrosting conditions of the 10 minutes that
have passed.