Honeywell heating systems with a combination boiler or added zones with no room thermostat. The existing wiring can be used to provide boiler interlock by fitting Sundial RF2 Pack 1. This has a timer to control heating and a built-in wireless transceiver to enable a wireless room thermostat, maintaining the traditional layout of separate time control and room thermostat. It can also be used on new systems. Because the room thermostat and the timer communicate, energy-saving and operating benefit

Brand Name	Honeywell