info Honeywell

Status Cool On (flashing) or Heat On (flashing)

Compressor protection feature is engaged — the system is waiting for a safe restart time before the compressor turns back on.

? What Causes This

The compressor was recently shut down and needs to wait a few minutes before safely restarting to prevent equipment damage.

What This Means

  1. Wait 5 minutes for the safe wait time to elapse.
  2. The flashing message will stop and the compressor will turn on automatically.
  3. Do not attempt to manually restart the compressor during this period.

Source: page 5 of the official manual

From the manual

Manual page 5 — Honeywell error Cool On (flashing) or Heat On (flashing)

This error code appears in:

Honeywell T4 Pro Programmable Thermostat (TH4110U2005/U)