ℹ
info Honeywell
Status Heat On / Cool On flashing
Compressor protection feature is engaged — Heat On or Cool On indicators flash on the screen.
? What Causes This
Compressor protection mode activated to prevent rapid cycling and equipment damage.
ⓘ What This Means
Wait 5 minutes for the system to restart safely without damage to the compressor.
Source: page 5 of the official manual
From the manual
This error code appears in:
Honeywell TH3110U2008 Thermostat