LG THERMA V, Installation Manual, Page: 120 / 277

120
ACCESSORIES INSTALLATION
ENGLISH
External Controller - Setting up programmable digital input
operation
If you require to operate control depending on external digital input(ON/OFF), connect cable to
indoor PCB(CN_EXT).
Follow below procedures step 1 ~ step 4.
Step 1. Check if the power of the unit is turned off.
Step 2. Disassemble front panels and distinguish control box(Indoor) of the unit
Step 3. Connect the external controller to PCB(CN_EXT) completely.
Step 4. Connect the cable and field installation part.
Determining the purpose of CN_EXT
Setting value: 0 ~ 5 step Indoor CN-EXT port setting
- 0: default
- 1: Simple operation on / off
- 2: Dry contact (simple contact)
- 3: Emergency stop only for indoor unit
- 4: Reattachment / absence
- 5: Emergency stop of all indoor units (It can be set only when indoor unit has emergency stop
function)
CN_EXT
Indoor PCB
Adapter Cable
CN_EXT
Indoor PCB
Adapter Cable
• SW : Single pole switch
- Select a part with contacts
for extremely low amperage
- DC 5 V ~ 12 V is used at the
contact point
- Switch load is approximately
0.5 ~ 1 mA
• Control cable
- Cable size : 22 to 26 AWG
- Don’t extend the cable more
than 10 meters
Indoor Unit
PCB
Supplied Part Field
Installation Part
SW
0.5 m
Max 10 m
CN_EXT
• X : Relay (a point of contact, fixed DC 0.5 ~ 1 mA)
• SW : Distance ON/OFF switch
• Control cable (Indoor unit to Relay Circuit)
- Cable size : 22 to 26 AWG
- Don’t extend the cable more than 10 meters
Installation example #2
Indoor Unit
Supplied Part
X
0.5 m
Max 10 m
X
Relay Circuit
Power
supply
of relay
SW
PCB
Field Installation Part
CN_EXT
Installation example #1
(For Split)
(For Hydrosplit)