User manual HONEYWELL DT90

[. . . ] When one of the buttons is first pressed, the setpoint temperature is shown flashing, accompanied by the · and · symbols. Further buttons presses will increase or decrease the setpoint in increments of 0. 5°C. Off/Standby Button, with Frost Protection The off/standby button allows DT90 to switch off the heating (or cooling) system at the touch of a button. To prevent accidental switch-off, the button must be held for 2 seconds to activate the change. [. . . ] As the temperature control element in the heating/cooling system, DT90 MUST be located in a position with good air circulation at average room temperature on an inside wall 1. 2 to 1. 5m from the floor. Do NOT position the thermostat near sources of heat (radiators, hot air vents, TV or lights), near doors or window, or in direct sunlight. Mounting DT90 can be mounted directly on the wall or onto an electrical wall box. The unit is supplied in 2 x halves, to enable quick and easy installation of the wiring backplate. CAUTION ­ isolate power supply and make safe before wiring the unit to prevent electric shock and equipment damage. Installation should be carried out by a qualified Electrician or competent Heating Engineer. Wiring DT90 is for fixed wiring only and must be installed in accordance with the latest Electrical Regulations. Ensure the wiring connection to the supply is via a fuse rated at no more than 8 amps and a switch having contact separation of at least 3mm in all poles (formerly Class "A"). Completing the Installation After wiring is complete, the front piece is attached to the backplate with a hinging action, until it clips into place. 4 EN0H 8578 UK07 R1 12/08 DT90 DIGITAL ROOM THERMOSTAT WIRING CONNECTIONS a. f. Boiler Boiler (potential free connection) Thermal actuator Zone valve Electric actuator Electric heat (maximum 1. 6kW direct switching) PRODUCT DIMENSIONS 5 EN0H 8578 UK07 R1 12/08 DT90 DIGITAL ROOM THERMOSTAT INSTALLER MODE ­ APPLICATIONS SETTINGS The DT90 has a special Installer Mode where some features can be adjusted to suit the application and the needs or lifestyle of the user. Each adjustable feature is called a Parameter. Parameter Minimum ON/OFF time Description and typical use DT90 is able to set a minimum limit for the on and off times of the controlled device or appliance, to prevent damage or excessive wear. This minimum time can be set to 1, 2, 3, 4, or 5 minutes, and is particularly important for heating applications with oil boilers, or air conditioning applications with compressors. Recommended settings are shown in the next table. Within the control proportional band, the output will be cycled several times per hour, to give precise temperature control. This can be set to 3, 6, 9, or 12 cycles, depending on the application. Recommended settings are shown in the next table. The proportional band is the temperature band, adjacent to the set temperature point, within which the thermostat will cycle the controlled output (to control the boiler, for example). Above or below this band the output will either be fully on or fully off. The band can be adjusted up to 3°C (default 1. 5°C) to provide improved temperature control. This is useful for (a) well-insulated homes with over-sized heating systems or (b) air systems with a fast response If the thermostat is located in a particularly hot/cold location and cannot be moved because of the wiring, then the measured/displayed temperature can be adjusted by +/- 3°C. This is useful if the homeowner wants the reading to match the temperature display on another appliance. The normal upper temperature limit of 35°C can be reduced as low as 21°C to save energy. The normal lower limit of 5°C can be raised as high as 21°C to protect inhabitants from the cold. On the DT90E ECO model, pressing the ECO button immediately puts the thermostat into energy saving mode, where it will control at this predefined temperature for as long as the user wishes. These are shown in the table below, followed by instructions on how to enter Installer Mode, how to select a parameter and change its value, and finally how to exit Installer Mode Description Minimum ON/OFF time Cycle rate Proportional band width Temperature measurement offset Upper setpoint limit Lower setpoint limit Energy saving ECO temperature (this parameter is only available on the DT90E model) Selection of heat/cool changeover Off/standby setpoint * Electric heat operation Parameter Ot Cr Pb tO uL LL ES Range of values 1, 2, 3, 4, 5 minutes 3, 6, 9, 12 cycles/hour 1. 5 to 3. 0°C -3 to 3°C 21 to 35°C 5 to 21°C 5 to 35°C Factory (default) value 1 minute 6 1. 5°C 0 35°C 5°C 18°C HC OS EH Reset parameters FS * In cooling mode the off/standby setpoint defaults to OFF To enter Installer Mode: a. [. . . ] These intellectual and property rights may include patent applications, registered designs, unregistered designs, registered trade marks, unregistered trade marks and copyrights. Honeywell reserves the right to modify this document, product and functionality without notice. This document replaces any previously issued instructions and is only applicable to the product(s) described. This product has been designed for applications as described within this document. [. . . ]