Hitachi RAC-10SH3, Руководство по обслуживанию, Страница: 92 / 153

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MODEL RAS-10SH , RAS-14SH , RAS-18SH
1. Power relay operation
Smoothing
capacitor
Operation command of
remote controller
· When the product becomes operable in response to remote control or other operation, the power
relay is turned on to power the outdoor unit.
· 6 minutes after there are no more turn-on factors, the power relay is turned off.
·
turned off.
If the terminal board is overheated due to a poorly inserted cable in the indoor terminal board, resulting in
the terminal board temperature fuse becoming melted down, the power to the operation coil of the power
relay is shut down and the relay is turned off to stop the power supply to the indoor unit. At the same time,
the power supply to the indoor/outdoor communication circuit will be shut down, resulting in the
communication function being stopped. (In that case, the failure display will consist of the timer lamp
blinking 3 times.)
12V
A A
B
C
B
C
s t r a p l a c ir t c e l e r o o d t u O s t r a p l a c ir t c e l e r o o d n I
Power relay
Power plug
Control
power
circuit
In
ver
ter
Terminal board
Temperature fuse
Power relay
ON signal
(from pin 87 of
microcomputer)
Indoor/outdoor
communication circuit
Indoor/outdoor
communication circuit
Operation sequence of relay
Power relay
0.7 second
Fig. 1-1
Check
DESCRIPTION OF MAIN CIRCUIT OPERATION
If the self-diagnosis function of the indoor and outdoor units detects failure mode, the power relay is
9 0
3 3 3