Nest A0003 Thermostat Operation Manual

The Nest A0003 is the Heat Link component of the 3rd Generation Learning Thermostat, designed for high-voltage systems (230V AC/50 Hz) in the UK and EU. It enables smart, Wi-Fi enabled control that learns your schedule for optimized comfort and energy savings. Supports various central heating systems including combi boilers, S-plan, Y-plan, and OpenTherm. Below are the key specifications and operation instructions.

Key Specifications

• Type: Heat Link for smart learning thermostat in high-voltage systems
• Compatibility:
  • Combi boilers, system boilers with hot water, S-plan, Y-plan, OpenTherm boilers
  • District heating with electrical control valve
  • Requires Wi-Fi for app control and updates
• Power Source:
  • Input: 230 V AC/50 Hz
  • Output: 12 V DC to thermostat
  • OpenTherm: 42 V DC max
• Electrical Rating:
  • Maximum cable thickness: 2 mm²
  • T1/T2: No polarity, connect to earth if used
• Temperature Range: Operating: 32°F to 104°F (0° to 40°C); ERP Class V
• Operating Conditions:
  • Humidity: Up to 90% RH
  • Wireless range: Ensure good connection, min 30 cm clearance
• Dimensions: Heat Link: Compact wall-mount design
• Features:
  • Modulating control for efficiency
  • Wireless connection to thermostat display
  • Compatible with Nest app for remote control
  • Energy-saving learning algorithms
• Thermostat Configuration Options:
  • Model A0001 display with A0003 Heat Link
  • EN 60730-1 compliant
  • Professional installation required

Operation Instructions

Initial Setup

1. Install Heat Link: Mount near boiler or junction box after wiring (see Section 3).
2. Power On: Switch on mains power; thermostat display begins setup.
3. Configure System:

• Select language, connect to Wi-Fi via app.
• Download Nest app, create account, tell about heating system.
• Thermostat starts learning schedule automatically.

Setting the Clock and Day

1. Syncs automatically via Wi-Fi connection.
2. Manual adjustment via app: Settings > Clock.
3. Set time zone, format, daylight savings.
4. Day auto-detected from usage and schedule.

Operating in Non-Programmable Mode

1. Select Mode: Turn dial to adjust temperature manually.
2. Adjust Temperature: Turn outer ring clockwise/counterclockwise.
3. Fan Control: Configured via app if applicable.
4. Manual Override: Temporary hold by turning ring; display shows status.

Operating in Programmable Mode

1. Factory Schedule: Auto-learns from adjustments and routines.
2. Custom Schedule:

• Use Nest app: Thermostat > Schedule.
• Set times/temperatures for periods.
• Enable learning for optimizations.

3. Temporary Override: Turn ring to adjust.
4. Permanent Hold: Set via app or menu.
5. Disable Programming: Switch to manual in app.

Advanced Features

1. Remote Control: Via Nest app with Wi-Fi.
2. Energy Saving: Home/Away Assist, Eco mode, Nest Leaf indicator.
3. Voice Control: Compatible with Google Assistant, Alexa.
4. HVAC Monitoring: Alerts for issues via app.
5. Sensors: Works with Nest Temperature Sensors.

Troubleshooting

• No Display: Check mains power, wiring; restart setup.
  
• No Heat: Verify mode, setpoint; check boiler/fuses.
  
• Wi-Fi Issues: Ensure signal strength, restart router/app.

Installation Instructions

Warning: High voltage. Install by professional only. Switch off mains power before starting. Do not connect thermostat directly to heating system.

Remove Old Thermostat

• Switch off mains power.
• Remove old thermostat cover, label/disconnect wires.
• Remove base from wall.

Installing New Thermostat

1. Install Heat Link: Connect L/N to power, T1/T2 to control wires; mount near boiler.
2. Mark mounting holes for base with level.
3. Drill holes, insert anchors, fasten base/trim plate.
4. Connect wires to T1/T2 on base.
5. Push excess wire into wall.
6. Snap display onto base; power on for setup.

Battery Location

• Built-in rechargeable battery in display.
• No user-replaceable batteries; powered via Heat Link.

Wiring and Configuration

Professional wiring required. No polarity on T1/T2.

System Type	Key Connections
OpenTherm	OT1/OT2 to boiler; 12V DC output
230V Combi Boiler	L/N power; OT1/OT2
S-Plan	Heating/water valves; OT1/OT2
Y-Plan	Zone/hot water valves; OT1/OT2
District Heating	Control valve; OT1/OT2

Caution: Ensure 30 cm clearance around Heat Link. Configure system type via app during setup.