Horstmann C-STAT17-M 7 Day Mains Operated Programmable Room Thermostat

The Horstmann Controls C-STAT17-M is a wall-mounted room thermostat from the C-Stat range of heating controls. It senses the air temperature in the room and switches the heating circuit on or off to hold the temperature set on the dial or display. It is used on domestic central heating systems where the thermostat is wired back to the boiler or to a wiring centre.

• The heating stays on when the room is already above the set temperature
• Rooms overheat, or never reach the temperature selected on the control
• The display is blank or flickering, or the buttons do not respond
• The boiler short-cycles because the thermostat switches in and out erratically
• Changing the set point has no effect on the heating

• Match the part number on the existing thermostat or its packaging against C-STAT17-M
• Confirm the control is a C-Stat 17 variant, as other models in the range use different terminal layouts
• Check whether a receiver or wiring centre is already installed on the system, as this affects how the thermostat is connected
• Note the existing wiring before removing the old unit so the replacement can be connected the same way