8.3.2 On / off room thermostat (low voltage) To be connected to contacts 6 and 7 of connector X4. This is a 24 volt connection and no mains power must be applied to these terminals. See chapter 13, electrical diagram. Note When a 24 volt thermostat is connected to contacts 6 and 7, the loop in 6 – 7 must be removed 5. The on/off room thermostat has to be connected to the contacts 6 and 7 of connector X4. 6. Adjust the feedback resistance of the room thermostat to 0.1 A. In case of doubt measure the current and adjust this accordingly. 7. The allowed maximum electrical resistance of the room thermostat and wiring is 15 Ohm.
8.3.3 Open Therm room thermostat Open therm is a protocol that enables the boiler and the room thermostat to communicate. Based on the information from the room thermostat the flow temperature of the boiler is adjusted to the most optimal value. The Open Therm (OT) room thermostat has te be connected to the contacts 11 and 12 of connector X4 (see chapter 13, electrical diagram). CAUTION Connecting the Open Therm room thermostat to other contacts than 11 – 12 may damage the room thermostat ! NOTE When an Open Therm thermostat is connected to contacts 11 and 12 of connector X4 , the loop in 6 – 7 must be removed.
8.3.4 Outside temperature sensor The appliance is equipped with a connection for an outside temperature sensor. The outside temperature sensor can be used in combination with an on/off room thermostat or an OpenTherm thermostat. Connect the outside temperature sensor (See § 8.3.1). For the heating line setting, see weather-dependent regulation (See § 10.6 ). The sensor should be fitted where possible on a north facing wall. 8.3.5 230 volt room thermostat To be connected to contacts 1 and 3 of connector X2. See electrical diagram.
NOTE When a 230V thermostat is connected, link in 6 - 7 of connector X4 must be removed Warning High Voltage Isolate the appliance from the electrical supply before connecting the thermostat. 8.3.6 S and Y zone plans Any combination of external controls for time /temperature and heating of external DHW cylinders or CH zones can be connected to the boiler. All controls/ zones should be connected in an external wiring centre and a switched live connected to 1 on X2. Set in-built timer to C-ON. NOTE When an external control is connected to contacts 1 and 3 of connector X2 the link in 6 - 7 of connector X4 must be removed Intergas Heating Ltd 27