Indoor Unit Operation - Samsung MH18ZC1(C2)-09 Service Manual

5-4-9 When the compressor does not operate
1) Inspection items
(1) Is the COMP A under the operating conditions? (cooling operating of A, B(C) room)
(2) Is the power voltage normal? (the rating voltage ±10% range)
(3) Are the connector connection of COMP A(RY 72, 73) and B(RY 71) good?
(4) The COMP A(B) is operated on and off in accordance with the operating conditions of
indoor unit of A (B. C) room.
2) Inspection sequence
Apply the outdoor power and operate the indoor unit A(B.,C)
in the cooling mode.
Is the comp A under the operating condition?
Has 3 minutes passed COMP A(B) after the power initial
and COMP on/off
Is comp A (B) on?
Is the voltage (the rating voltage ±10% range) shown
across the terminal of Comp A(B) power applied?
Is the voltage of pin no. 14, 13( 15) at low
Is the voltage of pin no. 50, 51 (52) of IC 04 (micom) at
high (DC 5V)?
Is comp A (B ) under the operating condition?
(comp A (B ) off)
* Comp A (B) operating conditions
(1) Comp A : Comp on /off control in accordance with the A room during the heating and cooling

indoor unit operation

(2) Comp B : Comp on /off control in accordance with the B(C) room during the heating and cool-
ing indoor unit operation
* Comp A( ) power measuring terminal
(1) Comp A measuring ; RY 73 (4) ↔ RY 72 (4)
(2) Comp B measuring ; RY 71 (4) ↔ RY 72 (4)
(3) Power input ; RY 72 (3) ↔ RY 73(3)
Samsung Electronics
Y
Y
N
*Refer to the power measuring terminal
N
(DC 0.7V)?
N
N
N
Normal
N
Normal (comp A (B ) off)
N
Keep Comp A (B ) off
Y
Y
Defect of comp A (B) and running condenser
Y
Defect of Ry 72, 73 (Comp B) and Ry 71(comp A) con-
tact and coil → Replace
Y
Defect of IC 06 output
Y
Defect of Ic 04 (micom)
BLK
RY72
(4)
(3)
BLK
WHT
RY71
(3) (4)
WHT
RED
RY73
(3) (4)
RED
Troubleshooting
Normal
→ Replace
→ Replace
→ Replace
5-15