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Wireless Temperature Sensor Troubleshooting

Applies to: CRFSW · CRFS2

Sensor not showing temperature in the app or on screen​

A zone shows no temperature reading or displays dashes.

Steps to resolve:

  1. Press the button on the sensor — if no lights flash, the battery needs replacing (CR2032)
  2. If the sensor flashes instead of showing solid red or blue, it needs re-pairing:
    • Press and hold the pair button on the sensor
    • In the iZone app, go to Menu → Devices and initiate pairing
  3. Ensure the sensor is within wireless range of the C225 CPU's RF antenna — add a CR Wireless Repeater if needed
  4. Check the sensor is not obstructed by furniture, inside a cabinet, or exposed to direct sunlight (causes inaccurate readings)

Sensor battery draining quickly​

The CR2032 battery needs replacement more frequently than expected.

Steps to resolve:

  1. Check if Scrooge Mode is disabled — when enabled, sensor reporting is reduced which can indicate low battery less clearly
  2. Ensure the sensor is within good RF range of the C225 — poor signal causes increased transmission retries and faster battery drain
  3. Keep sensors away from sources of RF interference (microwave ovens, cordless phones, other 433MHz devices)

Sensor showing incorrect temperature​

The displayed zone temperature does not match the actual room temperature.

Steps to resolve:

  1. Ensure the sensor is mounted at least 1.5m above the floor in a central location within the zone
  2. Check that the sensor is not in direct sunlight, near a supply air vent, or above a heat source
  3. Allow at least 30 minutes after powering on for the sensor to stabilise

Multiple sensors showing the same temperature​

All sensors display the same reading regardless of actual zone temperatures.

Steps to resolve:

  1. This can occur if Scrooge Mode is active — check Setup → Configure AC → Options → Scrooge Mode
  2. Verify each sensor is individually paired and listed under Menu → Devices with a unique device ID
  3. If sensors appear to share an ID, factory reset the duplicate sensor and re-pair it