Hitachi RAM-90QH5, Service Manual, Page: 37 / 83

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Unit 1
Heating
Heating
Compressor requirement
Request to Indoor
Unit 2
Unit 3
Unit 4
Unit 5
Unit 1
Unit 2
Unit 3
Unit 5
Unit 4
Turn on
for heating
Outdoor fan
480
0
480
0
480
0
480
0
Compressor
rotation speed
Unit 1
Unit 2
Expansion valve
Unit 3
Unit 4
Reversing
valve
Defrosting signal
Defrost request
Defrost request
[T_4BEN_DEF]
30 sec
15 sec
Defrosting
inhibit period Balancing period
[TDF414]
Reverse cycle period (max [DFMXTM])
Balancing period [TDF415]
Start sequence
[TSKTM1_W
*
]
[SDRCT1_W
*
]
[T_DFCTPS]
[PSTARTH2
*
]
[PSTARTH2
*
]
[DFCTPS$]
[DFCTPS$]
[PCLOSH$]
[PCLOSH$]
[DFPSMX$]
[DFPSMX$]
[DFCTPS$]
Hold
[DFCTPS$]
Hold
Hold
0 Palse
0 Palse
Hold
[DFSPPS$] Pulse/[TDFSPT] sec
[DFSPPS$] Pulse/[TDFSPT] sec
Defrosting sequence
[TSKTM2]
[DEFMAX]
[SDRCT2]
[DFSTEP]min
—1
/[TDFSPT] sec
30 sec
480
0
Unit 5 [PCLOSH$]
Hold
0 Palse
30 sec
MODEL RAM-90QH5
• Time chart when executing defrost (Unit 1 and Unit 2 operated, Unit 3, Unit 4 and Unit 5 stopped)