During Two-Cycle Heating Operation - Hitachi RAF-25NH4 Service Manual

During two-cycle heating operation

Defrosting signal
Defrosting request between
outdoor microcomputers
Unit 1
Unit 2
Unit 1
Unit 2
Unit 1
Unit 2
Turns on for
cooling
Turns on for
heating
Outdoor fan
Defrosting inhibit period
Compressor
rotation speed
520
480
Unit 1
0
520
480
Unit 2
0
Defrosting signal
Defrosting request between
outdoor microcomputers
Unit 1
Unit 2
Unit 1
Unit 2
Unit 1
Unit 2
Turns on for
cooling
Turns on for
heating
Outdoor fan
Defrosting inhibit period
Compressor
rotation speed
520
480
Unit 1
0
520
480
Unit 2
0
¥ See other sections for datails of expansion valve TD control, Æ N correction and distribution control.
※
¥ TSKTM1, SDRCT1, DFSTEP, TDFSPT, DEFMAX, DFCTPS, DFSPPS, DFPSMX, PSTART and PCLOSH are EEPROM data.
(main unit 1: thermostat on/main unit 2: operation stop/sub unit 1: thermostat on/sub unit 2: thermostat off)
Ⅰ
Defrosting request from sub
15s + sub delay component
Balancing period of 90s
30s
Hold
Hold
30s
Hold
PCLOSH
Hold
15s
Balancing period of 90s
Hold
30s
PCLOSH
Hold
Hold
Defrosting request
Reverse cycle period (max. 12 minutes)
¥Defrosting sequence
TSKTM1
DFSTEP min /
-1
TDFSPT sec.
SDRCT1
DFSPPS
pulse
DFCTPS
Defrosting request from main
Defrosting request
Defrosting request
Reverse cycle period (max. 12 minutes)
¥Defrosting sequence
30s TSKTM1
DFSTEP min
-1
TDFSPT sec.
SDRCT1
DFSPPS
pulse
DFCTPS
Hold
150
30s
Balancing period of 90s
DEFMAX
DFPSMX
Balancing period of 90s
DEFMAX
/
DFPSMX
TSKTM1
SDRCT1
15s
PSTART
DFCTPS
PCLOSH
30s
TSKTM1
SDRCT1
15s
PSTART
DFCTPS
PCLOSH