The Honeywell Home ST9100 is a single channel timer which has been designed primarily for control of a single heating area or alternatively combi boiler applications. ST9100 units are suitable for low voltage, mains or potential-free switching of the heating load. They benefit from a 7 day timer that gives fantastic flexibility by offering up to three on and off switchings per day which can of course be programmed differently. Suitable to be used with combi boilers or multi area systems where the user has different heating requirements from day to day. It can also be set to a 5/2 day or 1 day programme during fitting. All ST9100 benefit from an LCD display that gives clear English directions whenever any control is used. This means that fitters and users can use all of the controls easily, without needing to find an instruction guide. The timeswitch also features a ‘Holiday’ mode allowing the user to switch off their central heating for a specified number of days while they are away.  Features and Benefits: Large backlit LCD digital display which provides text feedback to assist with programming. Automatic 1 hour time change for summer winter solstice. Factory set time and date gives you or your installer less to set up. Temporary and permanent override features. Choose between 3 different built in programmes. Programme indicator lights advise which setting is currently in use. Designed to fit on industry standard back plate. Direct replacement for the older ST6100 models. Any settings programmed in are retained indefinitely. Use up to 3 on and off times per day. ‘Holiday’ mode. Returns Policy - Changed Your Mind? If you change your mind about the product when you receive it you can notify us any time within 365 days and return it for a full refund at your own cost. Any refunds will be made within 30 days of receiving your returned item. You are expected to cover the cost to return the item and your initial delivery charge will not be refunded. More details here