25.0 C, On/off switch and frost protection

Operation

On/off switch and frost protection

homexperttm by Honeywell THR840DUK Digital Thermostat

Heating or cooling control

25.0° C

Press and hold to turn on or off

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).

You can change the frost protection temperature to any level between 5º and 16º C, or turn this feature off so the heating system is never activated when the thermostat is off (see page 22).

Press and hold both buttons for 5 seconds

25.0° C

Heating changes to cooling

The thermostat is pre-set to control only your heating system. If installed and set up correctly, it can also be used to control your cooling system.

To switch between heating and cooling, press and hold the p and q buttons together until the screen changes.

NOTE: The thermostat will not switch to cooling control unless you enable this feature (see page 22).

NOTE: When you change the system, the “Heating” and “Cooling” symbols will appear for a few seconds, then disappear. Normally, these symbols appear only when the heating or cooling system is running.

	5.0°C
System maintains	Symbol appears when
minimum	thermostat is off
temperature when
thermostat is off

25.0° C