User Manual THR840DUK Digital Thermostat 50051982-001 Rev.
homexperttm by Honeywell THR840DUK Digital Thermostat Contents WARNING: This product must be correctly installed and configured to work properly (see pages 12-24). If you are not experienced in wiring electrical equipment, we recommend professional installation to avoid possible personal injury or equipment damage. TIP: After installation, see the QUICK START GUIDE on page 6 to customise and begin using your new thermostat right away. About your new thermostat Appendix What is a room thermostat?.......
User Manual homexperttm by Honeywell THR840DUK Digital Thermostat What is a room thermostat? ...an explanation for householders A room thermostat simply switches the heating system on and off as necessary. It works by sensing the air temperature, switching on the heating when the air temperature falls below the thermostat setting, and switching it off once this set temperature has been reached. Turning a room thermostat to a higher setting will not make the room heat up any faster.
User Manual homexperttm by Honeywell THR840DUK Digital Thermostat About your new thermostat Quick reference The THR840DUK is an easy-to-use thermostat designed to maintain a comfortable environment when you are at home and reduce energy costs when you are away. One touch of the ECO button overrides the normal temperature to maintain a lower, energy-saving level for a specified period of time (see page 11).
Operation homexperttm by Honeywell THR840DUK Digital Thermostat On/off switch and frost protection 25.0 °c Heating or cooling control Press the ON/OFF button as shown at left to turn the thermostat on or off. When off, the thermostat will never activate the cooling system, and will activate heating only if necessary to maintain a minimum indoor temperature of 5º C (frost protection).
Operation homexperttm by Honeywell THR840DUK Digital Thermostat Temperature control When idle, the thermostat displays the current room temperature. You can press the p or q buttons at any time to see the “target” temperature the thermostat is trying to maintain. Current room temperature 24.0 °c Press buttons to display or change target temperature 25.0 Energy-saving ECO mode One button press will display the target temperature, flashing.
Installation and Setup homexperttm by Honeywell THR840DUK Digital Thermostat System installation Wall bracket installation Installation procedure Remove the thermostat cover and use a screwdriver to pry open the tabs as shown at left, then remove the thermostat from the wall bracket. Install about 1.2 to 1.5 metres above the floor, where the display screen can be easily seen. 1 Disconnect electric power NO OK 2 Choose thermostat location and install wall bracket 3 Connect system wiring 1.2 — 1.
Installation and Setup homexperttm by Honeywell THR840DUK Digital Thermostat Connect system wiring Wiring diagrams Connect wiring from your heating or cooling equipment to the thermostat as shown at left. See wiring diagrams on pages 15-17 for details. Basic boiler Combi boiler 1 Make sure electrical power is off. 2 Strip insulation to expose about 6 mm of bare wire. 3 Use a screwdriver to loosen terminal screw, insert wire into slot, then tighten screw.
Installation and Setup homexperttm by Honeywell THR840DUK Digital Thermostat Wiring diagrams Wiring diagrams Thermal actuator Zone valve Electric resistance heater Zone valve (drive open, drive closed) L N 16 17
Installation and Setup homexperttm by Honeywell THR840DUK Digital Thermostat Activate batteries and mount thermostat System test Remove the thermostat cover (see page 13). Discard the plastic tab inside to activate the batteries, then replace batteries. The thermostat should display the current room temperature. Replace the thermostat front cover, then mount the thermostat on the wall bracket as shown at left. NOTE: This symbol will flash on the screen when battery power is low.
Installation and Setup homexperttm by Honeywell THR840DUK Digital Thermostat Installer setup Installer setup functions ** Factory default setting 25.0 °c Press and hold both buttons for 5 seconds i0se 0e: 1 Function Installer settings allow you to customise how your system works. Check the tables on pages 21-23 to see if any settings need to be changed.
Installation and Setup homexperttm by Honeywell THR840DUK Digital Thermostat Installer setup functions Customised settings for your system Enter Installer Setup (see page 27), then press p or q for access to system settings Function Description Setting Options Your heating system Changes required Setting Options 7: ES ECO default temperature 18°C ** Options: 5° to 35°C Standard gas boiler (<30kW) None No change 8: HC Heating/Cooling options 0: No central cooling system installed ** 1: All
Installation and Setup homexperttm by Honeywell THR840DUK Digital Thermostat Description of functions In case of difficulty Ot Minimum boiler off time: Check proper setting for your system (see page 23). LL Minimum temperature: When the q button is pressed, the thermostat will not allow a target temperature lower than the minimum you set. Cr Cycles per hour: Check proper setting for your system (see page 23).
Appendix homexperttm by Honeywell THR840DUK Digital Thermostat Limited Warranty Disposal and recycling Honeywell warrants this product for 1 year from date of purchase. We undertake to replace or repair at our discretion, products should they become defective within 1 year solely as a result of faulty materials and or workmanship.
Need Help? For assistance with this product please visit www.homexpertbyhoneywell.com, or call Honeywell Customer Care at 0845 604 2893. ® Honeywell The Arnold Centre Paycocke Road Basildon, Essex SS14 3EA Technical Help Desk: 0845 604 2893 50051982-001 Rev. A www.homexpertbyhoneywell.
