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5. Reversing valve control circuit
●
By reversing valve control circuit you can switch reversing valve ON/OFF (Heating ON) according to
instruction from indoor microcomputer and depending on operation condition.
Voltage at each point in each operation condition is approximately as shown below when measured by
tester. (When collector voltage of Q831 is measured)
Operation condition
Collector voltage of Q831
Cooling
Heating
Dehumidifying
General operation of Cooling
In normal heating operation
MAX. rotation speed instructed
by indoor microcomputer after
defrost is completed
Defrosting
Sensor dry
About 35V
About 0.8V
About 0.8V
About 35V
About 35V
Table 5-1
Fig. 5-1
Summary of Contents for RAM-18QH5E
Page 9: ... 8 ...
Page 10: ... 9 RAM 18QH5E MODEL RAM 18QH5E ...
Page 11: ... 10 ...
Page 12: ... 11 AC 220V 240V ONLY L N INDOOR 1 C1 D1 C2 D2 INDOOR 2 RAM 18QH5E ...
Page 13: ... 12 RAM 18QH5E ...
Page 21: ... 20 MODEL RAM 18QH5E WIRING DIAGRAM OUTDOOR UNIT ...
Page 23: ...PRINTED WIRING BOARD LOCATION DIAGRAM MODEL RAM 18QH5E 23 MOUNTING PCB SET TYPE ...
Page 25: ... 27 heating ff BASIC MODE MODEL RAM 18QH5E ...
Page 28: ... 33 Table 6 Table 7 ...
Page 29: ... 35 ...
Page 31: ... 37 ...
Page 56: ... 62 Fig 11 2 ...
Page 69: ... 75 1 Outdoor unit does not operate remote control signal can be received RAM 40QH5 ...
Page 71: ... 77 Lighting mode self diagnosis lamp 2 RAM 18QH5E ...
Page 72: ... 78 TROUBLESHOOTING OF THE SYSTEM POWER MODULE ...
Page 73: ... 79 ...
Page 74: ... 80 ...
Page 75: ... 81 ELECTRIC EXPANSION VALVE PIPE THERMISTOR POSITION CHARTS MODEL RAM 18QH5E ...
Page 78: ...HITACHI PM NO 0276E Printed in Malaysia RAM 18QH5E ...