9-4. Air conditioner operates, but abnormalities are observed.
9-4-1. Operation does not switch from HEAT to COOL (or COOL to HEAT).
• Indoor PCB Ass'y is defective.
• Check voltage between terminals
No. 4(+) and No. 6 at terminal plate.
(DC 24V)
No voltage appears.
Outdoor PCB Ass'y is defective.
OK
• Remote control unit may be defective.
• Measure resistance of 4–way valve's
winding.
Receiver in switch Ass'y may be
defective.
COOL
➞
HEAT
• Check voltage between terminals
No. 4(+) and No. 6 at terminal plate.
(0V)
HEAT
➞
COOL
44
