GENERAL AIRSTAGE TECHNICAL GUIDE
ARTH External Input Fire Shutdown
Using indoor-unit terminals 1 and 2 for simultaneous forced stop
Purpose: To shut down one or more ARTH indoor units when a fire alarm or other approved safety interlock operates, using the indoor-unit external input terminals.
Required configuration
ItemRequirement
Indoor-unit functionSet Function 46 to 02 – Forced Stop.
Input typeDry-contact input.
Input terminalsIndoor-unit terminals 1 and 2.
Cable22 AWG twisted pair, maximum 150 m.
RoutingKeep the control cable separated from mains and other power wiring.
Contact ratingUse a suitable dry contact for approximately DC 12–24 V, 1–15 mA.
Wiring arrangement
Fire alarm relay→COM to terminal 1+NO to terminal 2
For multiple indoor units, wire the same approved dry-contact signal in parallel to terminals 1 and 2 of each configured indoor unit.
Important: The fire alarm interface must provide a true volt-free contact. Do not apply an external voltage directly to terminals 1 and 2.
Flow chart 1 – Configuration and wiring
Identify every ARTH indoor unit requiring fire shutdown
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Set Function 46 = 02
Forced Stop mode on each indoor unit.
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Run 22 AWG twisted-pair cable
Maximum 150 m and separated from mains wiring.
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Wire fire relay COM to terminal 1 and NO to terminal 2
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For multiple units, parallel the dry-contact input to all configured indoor units
Operation logic
Fire relay stateIndoor-unit response
Dry contact CLOSEDForced Stop active. Indoor units stop immediately and normal controller operation is inhibited.
Dry contact OPENForced Stop released. Units return to normal control availability.
Flow chart 2 – Commissioning test
With fire alarm reset, confirm terminals 1–2 are open circuit
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Run all indoor units normally
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Activate the fire alarm relay
Dry contact should close.
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Do all configured indoor units stop immediately?
YES
Reset the alarm and continue the return-to-normal test.		 NO
Check Function 46, cable continuity, contact state and terminal connections.
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Reset the fire alarm so the dry contact opens
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Can the units now be operated normally?
YES
Commissioning is complete.		 NO
Confirm the relay has reopened and power-cycle the unit if required before further diagnosis.
Technician commissioning checklist
  • Verify all required indoor units are set to Function 46 = 02.
  • Verify terminals 1–2 are open circuit when the fire alarm is reset.
  • Verify the fire relay is a volt-free dry contact.
  • Trigger the fire alarm and confirm all units stop immediately.
  • Confirm local and remote controllers cannot restart the units while the contact remains closed.
  • Reset the fire alarm and confirm normal control is restored.
  • Label the fire-interface cable and record the tested relay contacts.
Safety and compliance: Fire-alarm interlocking must be designed, wired and commissioned by appropriately licensed personnel and must comply with the project fire strategy, applicable standards and local regulatory requirements. This guide covers the air-conditioning input arrangement only.
GENERAL AIRSTAGE | ARTH External Input Fire Shutdown Guide