How do I contact Honeywell for customer assistance or warranty service?

You can get assistance by visiting www.honeywell.com/yourhome or by calling Honeywell Customer Care toll free at 1-800-468-1502. Before calling, have the thermostat model number and date code available. The TH5110D is covered by a limited five-year warranty against defects in workmanship or materials under normal use. (Page 23)