GENERAL AIRSTAGE Technical Reference
AOTH90KRTA & AOTH72KRTA
Low Noise Mode External Input
External dry-contact control of outdoor unit Low Noise Mode
The AOTH90KRTA and AOTH72KRTA outdoor units support an external Low Noise Mode input. This allows the outdoor unit to reduce its operating noise when triggered by an external dry-contact device such as a timer, switch or compatible building control interface.
Connection Details
| Function | Low Noise Mode |
| Outdoor PCB connector | P580 |
| Input type | Dry contact / contact closure |
| Input ON | Contact closed |
| Input OFF | Contact open |
| Maximum wiring distance | 10 m from outdoor PCB to connected device |
| Contact capacity | DC 24 V or greater, 10 mA or greater |
| Optional connection kit | UTY-XWZXZ3 External Connect Kit |
How Low Noise Mode Operates
When the contact connected to P580 is closed, the outdoor unit enters Low Noise Mode.
When the contact is opened, the outdoor unit returns to normal operation.
| External Contact | Outdoor Unit Operation |
|---|---|
| OPEN | Normal operation |
| CLOSED | Low Noise Mode active |
Local Setting required:
The required Low Noise Mode level must also be configured through the outdoor unit's Local Setting procedure. The external contact then controls whether the configured Low Noise Mode is active.
The required Low Noise Mode level must also be configured through the outdoor unit's Local Setting procedure. The external contact then controls whether the configured Low Noise Mode is active.
Important - capacity may be reduced
Low Noise Mode reduces outdoor unit sound by limiting operation. As a result, available heating or cooling capacity may also decrease while Low Noise Mode is active, particularly under higher-load conditions or extreme outdoor temperatures.
This function should therefore only be used where reduced outdoor-unit noise is required and the potential reduction in available capacity is acceptable.
Low Noise Mode reduces outdoor unit sound by limiting operation. As a result, available heating or cooling capacity may also decrease while Low Noise Mode is active, particularly under higher-load conditions or extreme outdoor temperatures.
This function should therefore only be used where reduced outdoor-unit noise is required and the potential reduction in available capacity is acceptable.
Wiring
Connect the external control device to the P580 Low Noise Mode input on the outdoor unit control PCB.
Use the UTY-XWZXZ3 External Connect Kit where required to connect to the PCB.
Low Noise Mode Control Logic
External Timer / Switch / BMS Dry Contact
↓
UTY-XWZXZ3 External Connect Kit
↓
P580
Contact Open = Normal Operation
Contact Closed = Low Noise Mode
Contact Closed = Low Noise Mode
- The external device should provide a simple contact closure only.
- Maximum wiring distance between the outdoor PCB and external device is 10 metres.
- Confirm all wiring and local settings before operating the system.
Typical Applications
Low Noise Mode may be useful where reduced outdoor-unit sound levels are required during specific periods, including:
| Night-time operation | Reduce outdoor-unit noise during selected night-time periods. |
| Noise-sensitive locations | Applications where outdoor-unit sound requires additional management. |
| Timer control | Automatically activate Low Noise Mode during predetermined periods. |
| Building control | Interface with a compatible external control or building-management system using a dry contact. |
Related External Inputs & Outputs
The AOTH90KRTA also provides the following external control connections:
| Connector | Function |
|---|---|
| P580 | Low Noise Mode input |
| PA580 | Peak Cut Mode input |
| P590 | Error Status output |
| PA590 | Compressor Status output |
Electrical safety
Always isolate power to the air conditioning system before accessing or wiring the outdoor unit PCB. External control wiring should only be carried out by suitably qualified personnel in accordance with the applicable installation and service documentation.
Always isolate power to the air conditioning system before accessing or wiring the outdoor unit PCB. External control wiring should only be carried out by suitably qualified personnel in accordance with the applicable installation and service documentation.