Safety first: Turn off power to the HVAC system and any connected ventilator at the breakers.

Steps to troubleshoot:

1. Verify configuration: In the thermostat’s advanced setup, confirm that a ventilator is only enabled if a Bryant-compatible ERV/HRV is installed. Disable ventilation in the menu if no device is present.
2. Inspect ventilator wiring: At the indoor unit or ventilator junction box, check that the control wires from the thermostat/indoor board are correctly landed on the Bryant ventilator terminals. Tighten loose connections.
3. Check for incompatible devices: If a non-Bryant ERV/HRV is connected directly to the communicating thermostat terminals, disconnect it and use dry-contact control or a separate controller as recommended by Bryant.
4. Test ventilator operation: With power restored, command ventilation from the thermostat and listen for the ventilator to start. If it does not run and E8 persists, the ventilator control module may be faulty.
5. Professional service: Ventilator control boards and wiring should be tested by a technician familiar with Bryant ventilation products.

Thermostat displays E8 and ventilation or ERV/HRV functions are disabled.

Possible Causes