Changing The Number Of Units To Be Operated - Hitachi RAF-25NH4 Service Manual

CHANGING THE NUMBER OF UNITS TO BE OPERATED

¥ The following shows the operation status when the number of units to be operated is changed from 2 to 1,
thermostat off, 1, 2 and then operation stop.
[Cooling]
Unit 1
Cooling
Unit 2
Cooling
Heating output
Cooling output
Turns on
for cooling
Turns on
for heating
Outdoor fan
Hi
CMAX2
Compressor
rotation speed
520
480
Unit 1
0
520
< TD control + ÆN correction + distribution control >
480
Unit 2
0
2 to 1 unit
[Heating]
Unit 1
Heating
Unit 2
Heating
Heating output
Cooling output
Tums on
for cooling
Tums on
for heating
Outdoor fan
Hi
WMAX2
Compressor
rotation speed
520
480
+100 pulses
Unit 1
0
520
480
< TD control + ÆN correction + distribution control >
Unit 2
0
2 to 1 unit
¥ See other sections for details of expansion valve TD control, ÆN correction and distribution control.
※
¥ CMAX1, CMAX2, WMAX1, WMAX2, TSKTM1, SDRCT1, PSTART, PSTARTH and PCLOSH are EEPROM data.
Thermostat off
Thermostat off
15s
Lo
Balancing for 3 minutes
CMAX1
5s
80s
Thermostat off 1 unit to be operated
Thermostat off
Thermostat off
15s
Lo
Balancing for 3minutes
WMAX1
60s
80s
Thermostat off 1 unit to be operated
Cooling
Lo
TSKTM1
Start sequence
CMAX1
SDRCT1
< TD control + ÆN correction + distribution control >
[ Outdoor temperature < 40ûC ]
< TD control + ÆN correction + distribution control >
PSTART
Heating
Lo
TSKTM1
Start sequence
WMAX1
SDRCT1
< TD control + ÆN correction + distribution control >
PCLOSH
[ Outdoor temperature < 40ûC ]
< TD control + ÆN correction + distribution control >
PSTART
144
Cooling
15s
Hi
Balancing for 3 minutes
CMAX2
PSTARTH
[ Outdoor temperature 40ûC ]
≧
1 to 2 units Operation stopped
Heating
Hi
Balancing for 3 minutes
WMAX2
PSTART
[ Outdoor temperature 40ûC ]
≧
1 to 2 units Operation stopped
Operation stopped
Operation stopped
30s
80s
Operation stopped
Operation stopped
15s
80s