13-22
TROUBLESHOOTING
SM OU12HP 2-E.2 GB
13.5.17 Checking Indoor-Outdoor Unit Communications
1) Disconnect the wire cable from the connectors on both sides (main board and terminal block),
check the wiring continuity – Repair or replace wiring if needed.
2) Check the continuity of the connecting wiring between indoor and outdoor units – Repair or
replace wiring if needed.
3) Problem could be either in outdoor unit main board or indoor unit controller. To verify which one
is faulty use additional boards and replace the one which is faulty.
Replacing Outdoor Unit main board - (14.1.13)
Replacing Indoor unit electrical assembly - (14.2.2)
13.5.18 Checking Indoor Unit Fuse on Controller
If the 3.15A fuse on the main Board is burnt check the fan or any other peripheral that can cause a
short:
1) In case of a problematic peripheral - replace it.
2) In case no problematic peripheral replace the burnt fuse.
3) In case of frequent burning fuse, replace the controller.
Replacing Indoor unit electrical assembly - (14.2.2)
13.5.19 Checking Indoor Unit Fan Motor
1) Check the motor wiring from the controller.
2) Check the motor capacitor for capacitance according to the capacitor name plate.
3) Check the resistance between each coil of the motor to be within normal range (30-300:).
4) Check resistance between each wire to ground to be above 5:.
Replacing Indoor unit Fan Motor - (14.2.6)
Replacing Indoor unit electrical assembly - (14.2.2)
Replacing motor capacitor - (14.2.8)
13.5.20 Checking for electromagnetic interference (EMC problems)
13.5.20.1 EMC interference to the A/C unit
Locations most susceptible to interference
1) Locations near broadcast stations where there are strong electromagnetic waves.
2) Locations near amateur radio (short wave) stations.
3) Locations near electronic sewing machines and arc-welding machines.
Problem:
1) The unit may stop suddenly during operation.
2) Indicator lamps may flicker
Correction Actions:
The fundamental concept is to make the system less susceptible to noise by Insulation for noise or
distance from the noise source.
1) Use shielded wires.
2) Move unit away from the noise source.
13.5.20.2 EMC interference to near by home appliances
Locations most susceptible to interference:
1) A television or radio is located near the A/C and A/C wiring.
2) The antenna cable for a television or radio is located close to the A/C and A/C wiring.
3) Locations where television and radio signals are weak.
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