Mitsubishi Electric HP120TNU-A Service Handbook page 143

[5-2 Outdoor Unit Control ]
2) When combination of units
For a combination of units, operation is split so that there is a unit for defrosting and a unit for the heating operation. If one of
the combination of units is operated, the stopped unit is started, the unit that was operating is defrosted, and then the unit that
was stopped before the control began is defrosted. At that time, operation by the outdoor units that make up the combination
is as shown in the table below.
Outdoor unit fan 1
Outdoor unit fan 2
SV1a
SV2
LEV2a
LEV2b
LEV2c
LEV2d
21S4a
21S4b
21S4c
*1 The valve will turn off if TH4>80°C is met while defrosting of the second unit is performed while the unit is in operation.
(3) Continuous heating mode end conditions
Continuous heating mode will end when the Continuous heating mode time in the table below is reached.
Continuous heating mode time
When the Continuous heating mode ends, the frequency is reduced once.
18
- chapter 5
Unit in defrost cycle
Stopped
Stopped
*1
ON
*1
ON
1000 According to refrigerant
equalization control
1000 According to refrigerant
equalization control
-
6000 According to refrigerant
equalization control
OFF
OFF
-
Single unit
When 10 minutes have passed When 10 minutes have passed
Unit in operation
In operation
In operation
OFF
OFF
ON
ON
Combination units
HWE18220_GB