Hitachi RAF-25NH4 Données Techniques page 137

PROCESSING AT OVERHEAT THERMISTOR (OH) HIGH TEMPERATURE
Restriction Start Conditions
◇
[Operating two units] in common for cooling and heating
¥ When either expansion valve counts 480 pulses and the OH temperature
100 min -1 / 30 second.
[Operating one unit for cooling]
¥ When the expansion valve of the operated unit counts 480 pulses and the OH temperature
decrease at a rate of 100 min
[Operating one unit for heating]
¥ When the expansion valve of the operated unit counts 480 pulses and the OH temperature
unit will open until 250 pulses are counted at a rate of 20 pulses / 20 second.
¥ When the expansion valve of the operated unit counts 480 pulses and the OH temperature
decrease at a rate of 100 min
¥ The decreasing rotation speed is based on that when reduction processing is started and will hold until decreasing is finished. However,
※
the reference rotation speed will be replaced only when the target speed is lower than that when reduction processing was started.
¥ Reduction of compressor speed is inhibited when the OH temperature is between 94
before.
Restriction Release Condition (in common for all)
◇
¥ Restriction is released when the OH temperature
restore the target speed.
When two units are operated for heating:
Unit 1
Unit 2
Cooling output
Heating output
Turns on
for cooling
Turns on
for heating
Outdoor fan
97¼C
OH
94¼C
temperature
Compressor
rotation speed
520
480
Unit 1
0
520
480
Unit 2
0
¥ Operation when two units are operated for cooling is similar to that shown above.
※
¥ WMAX2 and MINRPM are EEPROM data.
¥ See other sections for details of expansion valve TD control, ÆN correction and distribution control.
-1 / 30 second.
-1 / 30 second.
＜
WMAX2
Decreases by 100 min
20s 20s
Hold
Hold 500ms
Hold
Hold 500ms
97
＞ ℃ ⇒
94 and the compressor speed increases at a rate of 50 min
℃
Increases by 50 min
-1 /30s
MINRPM
156
the compressor speed will decrease at a rate of
97 the compressor speed will
＞ ℃ ⇒
97 the expansion valve of stopped
≧ ℃ ⇒
97 the compressor speed will
＞ ℃ ⇒
and 97 and does not rise from 30 seconds
℃ ℃
-1 /30s
20s 20s 20s
-1 / 30 second to
WMAX2