Hitachi RAC-18GH5, Service Manual

●

  The air de

fl

 ector control operation shown below is done when the swing switch 

is pressed or when the operation mode is changed.

●

  The air de

fl

 ector control operation shown below is done when the operation 

switch is turned off.

Item

3-way

AUTO (Swing)

Speci

fi

 cation

Cooling/ 
dehumidi-
fying

Heating

(When the 
operation 
switch is 
turned off 
Automatic 
shut opera-
tion)

Air
blowing
direction
control

8

The same as cooling 

●

 dehumidifying

Other detailed speci

fi

 cations

1.  When the room temperature starts to 

increase within 3 minutes after thermo 
OFF in “cooling” and fan speed “AUTO”, 
the fan speed changes L 

→

 M 

→

 H as 

when thermo ON.

2.  If “cooling” is selected during “sensor 

dehumidi

fi

 cation” operation the operation 

continues as it is with the thermo ON. 
The 3 minutes delay is not started. The 
set temperature and fan speed depend 
on the remote control signal.

It is same for “cooling” – – – – “sensor 
dehumidi

fi

 cation”. It is same for “AUTO” 

sensor dehumidi

fi

 cation cooling “sensor 

dehumidi

fi

 cation”  “cooling”.

3.  The filter sign lights after 200 hours 

operation of the room fan. The lamp goes 
out when the POWER SWITCH set to 
OFF and ON again.

4.  After the failure mode is started (indicator 

lamp 

fl

 ickering), rapid mode changing 

cannot be done.

5.  If the operation is made by the nice 

temperature reservation during the 
sleep operation, the normal operation 
continuously occurs, and for the advance 
time, the temperature difference between 
the set temperature without sleep shift 
and “room temperature” is used.

– 45 –

●

  Operation starts in advance so that the room temperature reaches 

the preset value at the set time.

●

  The operation time is obtained as follows depending on the room 

temperature when operation starts.

(1) Calculation method of the moved-up time.
 

Moved-up time (MT) = Moved-up time depending on the temperature 
difference (OT) + compensation time (HT).

MT is at least 1 minute if OT is not zero.

Heating 

Cooling

(MT) 

00 ~ 60 min. 

00 ~ 60 min.

(OT) 

00 ~ 60 min. 

00 ~ 60 min.

(HT) 

–60 ~ 60 min. 

–60 ~ 60 min.

Obtain OT (moved-up time depending on the temperature difference) 
from the table below.

10

“NICE
TEMPERA-
TURE”
reservation

 Heating 

Cooling

  Setting temp.  –  Room temp.  Time (min.)  Setting temp.  –  Room temp.  Time (min.)
  00  – 01.00 

00 

00.00 – 02.00 

00

 01.25 – 03.00 

10 

02.25 – 05.00 

15

 03.25 – 07.00 

20 

05.25 – 08.00 

30

 07.25 – 10.00 

30 

08.25 – 11.00 

45

 10.25 – 13.00 

40 

11.25 – 

60

 13.25 – 16.00 

50

 16.25 – 19.00 

60

 19.25 – 22.00 

60

 22.25 –

❈

 The preset temperature value shown above does not 

include any shift value.

(2) Compensation

1  The “Attained” state is monitored and a “Not attained” check is 

done to revise the compensation time (HT).

 “Attained” monitor
  Continuously monitored during “NICE TEMPERATURE” operation.

(Heating)

When the room temperature < Set value + compensation shift, 
it is regarded to be “attained” and 5 minutes are reduced from 
the compensation time.

(Cooling)

When the room temperature < Set value + compensation shift, 
it’s operated same as above.

  “Not attained” check
  Performed once when the “NICE TEMPERATURE” timer is completed.

(Heating)

When the room temperature < Set value + compensation shift 
1°C, it is regarded to be “Not attained” and 5 minutes are added 
to the compensation time.

(Cooling)

When the room temperature > Set value + compensation shift 
+1°C, it’s operated same as above.

❈

 If the room temperature is 1°C from the set value + 

compensation shift, compensation is not done.

Item

 ON 

temperature

Thermostat operation  (Thermostat relay)
 

power relay (°C)

 Differential 

(°C)

Low-temperature defrosting

Cooling, sensor
dehumidi

fi

 cation

(T1)

RAS-18GH5

 16 

17.6

 24 

25.6

33.6

0.33

 ON 

(°C) 

4.0

 Reset (°C) 

12.0

Table 2 Sensor operation values

Item  

RAS-18GH

 Automatic 

Yes

 Heating 

Yes

Operation switching 

Sensor dehumidi

fi

 cation 

Yes

 Cooling 

Yes

 Fan 

Yes

Temporary switch 

Yes (automatic)

Service switch 

Cooling 

Yes

Nice temperature reservation 

Yes

Defrosting  

Yes

Sleep circuit 

Yes

Heater operation at the time of sensor dehumidi

fi

 cation 

No

Automatic blowing direction 

Yes

Filter sign 

Yes

Wireless mode 

Heat and Cool wireless

Table 1 Speci

fi

 cations

Down

Up

Down

Up

❈

 Swing start direction

5