Service Interval Feature Expalined

The Service Interval (Si) feature on a programmable room thermostat is designed to help landlords comply with current gas regulations. When activated, the Si feature will give a warning message to the householder that their boiler is due to be serviced. If the boiler has not been service by the Service Due date then the programmable room thermostat will enter "Setback" mode. The Setback mode forces the set temperature of the programmable room thermostat to a fixed, lower than normal temperature (usually around 14°C), meaning that the building is uncomfortable for the occupants but is protected from extremely low temperatures. When the boiler has been serviced the Service Engineer will normally reset the Si feature, meaning the unit will return to normal operation until the next service is due.

When resetting or activating the Si feature the service engineer will be prompted to enter two numbers. The first number  is the number of days before the Service Due date that the landlord wishes the service due warning message ("Ser") to be displayed on the screen of the unit. In the case of the SunStat Si & SunStatRF Si this number is between 30 and 60 days. The second number the service engineer will then be prompted to enter is the number of days (between 0 and 365 days) until the next service is due.

The SunStatRF Si & SunStat Si are supplied with this feature disabled and must be selected by the installer. Once selected this feature cannot be disabled by the householder unless they have access to a hidden key sequence.