Troubleshooting Guide - Honeywell CM921 User Manual

Troubleshooting Guide

Symptom
The thermostat has a blank LCD
screen.
The thermostat shows a lashing
symbol on the LCD screen.
The thermostat's LCD display
shows a symbol but the
heating does not switch on.
The thermostat shows a lashing
symbol on the LCD
screen.
Possible Cause
Batteries not installed.
Incorrect battery orientation.
Exhausted batteries.
Batteries are exhausted and
need replacing.
The heating is not required
at this moment.
Fault in thermostat
Remedy
Check to see if there are batteries in the battery
compartment and the paper tab has been removed.
Check that the batteries have been installed in the
correctorientation.
Replace with new batteries.
Replace with new batteries.
The heat demand is send to the HC60NG as a value
between 0-100%. The HC60NG will adjust the boiler
on time to meet this requirement. That is why the
heating will be off sometimes even if the
displayed. To check if RF system is communicating
properly press the button to increase the set
temperature a few degrees above the current
temperature. The heating should come on after a few
seconds.
Remove and re-insert the batteries in the thermostat.
If the symbol does not clear itself in a few
minutes call the installer.
symbol is