Basic Cooling Operation - Hitachi RAS-25CNH1 Service Manual

Room temp.
Preset temperature
for cooling
(+) SHIFTC
Fan speed
"auto" setting
Start
Start/stop switch
Thermostat judgement
Super Hi
Hi
Indoor
Med
unit fan
Lo
Super Lo
Operation lamp
1 min. 3 min.
Maximum
(CMAX)
Fixed rotation period
Rated
speed
(CSTD)
3000
Minimum
(CMIN)
0
Outdoor fan
Reversing Valve
(Heating ON mode)
Note:
(1) Conditions to start Cool dash operation are as follows. When the operation starts with the "AUTO" or "Hi" fan speed or when the fan speed is changed to "Hi" during cooling operation, if the temperature difference between the room
temperature with the compressor rotating at maximum speed and the preset temperature is (
(2) Conditions for releasing Cool dash operation (compressor maximum rotation speed period) are as follows.
1 Cool dash has been continued for 25 minutes.
The room temperature reaches the cooling preset temperature (including cooling shift value) -1˚C and then the room temperature ≥ preset temperature -0.66˚C is reached after the fixed rotation period has elapsed.
2
3 The thermostat is turned OFF.
(Ehen Cool dash is released by above 1, Pl control starts without operating for fixed rotation period.)
(3) The thermostat OFF temperature during Cool dash operation is cooling preset temperature (including cooling shift value) +3˚C, and after the thermostat is turned OFF, Cool dash is finished and Pl control starts.
(4) The minimum ON time of the compressor is 3 minutes, and minimum OFF time is also 3 minutes.
(5) The compressor speed in the fixed rotation period after releasing Cool dash maximum speed is the minimum speed (CMIN).
(6) The time limit to keep the maximum speed (CMAX) of the compressor in the normal cooling operation (other than Cool dash) is within 60 minutes when the room temperature is CLMXTP or less. If the room temperature is more than
CLMXTP, there is no time limit.
(7) When the fan speed setting of the remote control is "Med", the maximum compressor speed is CJKMAX.
(8) When the fan speed setting of the remote control is "Lo", the maximum compressor rotation speed is COZMAX.
(9) When the fan speed setting of the remote control is "Hi", and both the room temperature and external temperature (data from the outdoor unit) satisfy the dewing condition shown in Table 2, the maximum compressor speed is
CKYMAX. (This control is effective only when external temperature data is provided.)

BASIC COOLING OPERATION

CLMXTP
Stop Start
15 sec.
TCMAX: refer to Table 1) or more, Cool dash will start.
Stop
Thermostat
OFF
1 min.
15 sec. 15 sec.
Table 1 TCMAX Table 2 Dewing condition judgement value
Max. speed (CMAX) — Room temp. — Preset
Min. speed (CMIN) temp. (including shift)
650min -1 1.66˚C
750min -1 2.00˚C
800min -1 2.33˚C
850min -1 2.66˚C
950min -1 3.00˚C
1000min -1 3.33˚C
1050min -1 3.66˚C
1150min -1 4.00˚C
1200min -1 4.33˚C
1250min -1 4.66˚C
1350min -1 5.00˚C
1400min -1 5.33˚C
1450min -1 5.66˚C
-1
1550min 6.00˚C
1600min -1 6.33˚C
1650min -1 6.66˚C
Note:
1. Refer to data in page 41 Table 1 for each constant shown by capital letters in the diagram.
Item Temperature
Dewing
30˚C
condition (ON)
Dewing
32˚C
condition (OFF)
Dewing
32˚C
condition (ON)
Dewing
34˚C
condition (OFF)
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