Broan-NuTone C907 Doorbell Transformer Instruction Manual

Introduction

The Broan-NuTone C907 Doorbell Transformer is designed to provide reliable power for your doorbell system. This 16-volt, 30VA transformer is suitable for powering up to three doorbells and is compatible with various smart video doorbells. It features an easy-to-install lock-mount or wall-mount design and includes a thermal cut-off switch for safety.

Image: The Broan-NuTone C907 Doorbell Transformer, a compact metal unit with two screw terminals on a red base.

Safety Information

• WARNING: Risk of electric shock. Disconnect power at the circuit breaker or fuse box before installation or servicing.
• Installation should be performed by a qualified electrician or in accordance with local electrical codes.
• Ensure the transformer is installed in a dry location, protected from moisture.
• The thermal cut-off switch is designed to shut off the system in case of excessive temperature. Do not bypass or tamper with this safety feature.
• Verify voltage and VA requirements of your doorbell system before connecting the transformer.

Image: The C907 transformer showing the "cULus LISTED" label, indicating compliance with safety standards.

Package Contents

The package contains the following item:

• Broan-NuTone C907 Doorbell Transformer (1 unit)

Setup and Installation

The C907 transformer is designed for easy installation, compatible with standard single-gang junction boxes. It can be mounted using a lock-mount or wall-mount method.

Tools Required:

• Screwdriver (Phillips and/or flathead)
• Wire strippers
• Voltage tester
• Pliers

Installation Steps:

1. Disconnect Power: Before beginning any electrical work, turn off power to the circuit at the main electrical panel. Verify power is off using a voltage tester.
2. Mount the Transformer: The transformer can be mounted directly to a standard single-gang junction box. Secure the transformer using the integrated lock-mount or by screwing it to a wall surface near the junction box.
3. Connect High Voltage Wires (120V AC):
   • Connect the black wire from the transformer to the hot (usually black) wire from the power source.
   • Connect the white wire from the transformer to the neutral (usually white) wire from the power source.
   • Connect the green wire from the transformer to the ground (usually green or bare copper) wire from the power source.
   Ensure all connections are secure with appropriate wire connectors.
4. Connect Low Voltage Wires (16V AC):
   • Connect the low voltage wires from your doorbell chime and doorbell button to the two screw terminals on the transformer.
   • The transformer provides 16V AC output. Refer to your doorbell chime and button wiring diagrams for specific connections.
5. Secure Wiring: Ensure all wiring is neatly tucked into the junction box and any covers are securely fastened.
6. Restore Power: Turn the power back on at the main electrical panel.
7. Test System: Test your doorbell system to ensure proper operation.

Image: The C907 transformer showing the high-voltage input wires (black, white, green) and the low-voltage output terminals.

Image: Close-up view of the two low-voltage screw terminals on the C907 transformer.

Operating Instructions

Once properly installed, the Broan-NuTone C907 transformer continuously supplies 16 volts of alternating current (AC) at 30 volt-amperes (VA) to your doorbell system. This power is sufficient for operating up to three standard doorbells or compatible smart video doorbells. The transformer operates silently and requires no user interaction after installation.

Maintenance

The Broan-NuTone C907 transformer is designed for maintenance-free operation. Periodically, it is recommended to:

• Inspect the wiring connections for any signs of wear or looseness. Ensure power is disconnected before inspection.
• Keep the area around the transformer clean and free from dust or debris to ensure proper heat dissipation.
• Ensure the transformer remains in a dry environment.

Troubleshooting

If your doorbell system is not functioning correctly after installing the C907 transformer, consider the following:

• No Power to Doorbell/Chime:
  • Check the circuit breaker or fuse for the circuit supplying power to the transformer.
  • Verify all high-voltage (120V AC) connections to the transformer are secure.
  • Ensure the low-voltage wires are correctly connected to the transformer terminals and to the doorbell chime/button.
• Smart Video Doorbell Issues (e.g., intermittent power, offline status):
  • Many smart video doorbells require a minimum of 16V AC and sufficient VA (typically 30VA) for stable operation. The C907 provides 16V 30VA, which is generally recommended.
  • Ensure the doorbell's internal settings (if applicable) are configured for a mechanical chime or the correct power source.
  • If issues persist, consult the specific smart doorbell manufacturer's troubleshooting guide.
• Chime Not Ringing Fully or Weakly:
  • This can occur if the chime mechanism requires more power than supplied or if there's a long wire run causing voltage drop. The 30VA rating of the C907 is designed to mitigate this for most systems.
  • Check for loose connections at the chime unit or doorbell button.
• Transformer Overheating/Shutting Off:
  • The transformer has a thermal cut-off switch. If it's overheating, it may indicate an overload or a short circuit in the low-voltage wiring.
  • Disconnect power and inspect all low-voltage wiring for shorts or damage.
  • Ensure the total VA requirement of all connected doorbells/chimes does not exceed 30VA.

Specifications

Warranty Information

The Broan-NuTone C907 Doorbell Transformer comes with a one-year limited warranty from the date of purchase. This warranty covers defects in materials and workmanship under normal use. For specific terms and conditions, please refer to the warranty documentation included with your product or contact Broan-NuTone customer support.

Support

For technical assistance, installation questions, or warranty claims, please contact Broan-NuTone customer support. You can typically find contact information on the manufacturer's official website or within the product packaging.

When contacting support, please have your product model number (C907) and date of purchase available.