Heat Annunciator Not Displayed — Supplemental heat not activating

What does Heat Annunciator Not Displayed mean?

The slave thermostat does not activate supplemental or auxiliary heat even when there is a heating demand of 1.5° F or more. The 'HEAT' annunciator (indicator) is not shown on the display.

• Slave thermostat zone heating demand is less than 1.5° F.
• The 'Zone Supplemental Heat' option (rotary switch position F4) is not configured ON.
• The 'Supplemental Heat Time Guard' has not expired (a delay after startup, reset, or de-energizing).
• The slave thermostat has active 'HF' (Hardware Failure) or 'SF' (Storage Failure) errors that are locking out supplemental heat.
• Incorrect configuration of the system controller's options, such as the 'Monitor Thermostat Heating Lockout Temperature' set point.

Click steps to track your progress.

1. 1

   Ensure the slave thermostat zone heating demand is equal to or greater than 1.5° F.

2. 2

   Verify that the 'Zone Supplemental Heat' option (rotary switch position F4) is configured to ON.

3. 3

   Allow the 'Supplemental Heat Time Guard' to expire, or use the 'Supplemental Heat Time Guard Override' (rotary switch position F1, toggle display to ON) to temporarily reduce the time guard to 30 seconds for one cycle.

4. 4

   Check for 'HF' or 'SF' errors on the slave thermostat display (ensure 'Error Code Display' F11 is ON).

5. 5

   Check the configuration of the system controller associated with the slave thermostat for any options that could be locking out supplemental heat, such as the 'Monitor Thermostat Heating Lockout Temperature' set point.