Samsung ASHM070VE Service Manual page 44

Troubleshooting
5-3-8 When the 4 way valve (A,B) is not operating
1. Inspection items
(1) A re the 4 way valve A and B under the operating conditions?
(When the COMP A (4 way valve A ) and COMP B (4 way valve B) are on during the
heating operating)
(2) Is the power voltage normal? (AC 198- AC 264V)
(3) Is the connecting of 4 way valve A (CN 75) and B (CN 76) good?
2) Inspection sequence
Put off the outdoor unit power and put it on again after 5 seconds.
Select the heating operation of A(B) room by the remote controller.
Has 3 minutes passed after selection of A(B) room heating?
Is the 4 way valve A(B) on?
Is the voltage (AC 198V - 264 V ) shown across the 4 way
valve A(B) connector (CN 75, CN 76) ?
Is the pin no 47(46) of IC 04 ( MICOM) at high (DC 5V) ?
Is the 4 way valve A (B) under operating conditions?
*4 way valve operating conditions
(1) During the defrost control, put the 4 way valve A(B) off .
(2) During the heating operation put the 4 way valve A(B) on.
(3) The changeover of heating to cooling : put the 4 way valve off immediately (in case of B and C
ro o m ) .
(4) The changeover of cooling to heating : it is on after 50 seconds delay.
5-12
Y
N
N
N
N
Normal
N
Keep 4 way valve off.
Y
Y
Defect of RY 76 (RY 77) contact and coil →Replace
Y
Defect of IC 06 (IC 07 ) output →Replace
Y
Defect of IC 04(MICOM) - replace the IC 04 or PCB
Normal
the Relay
ass'y
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