I’ve just wired up a hive thermostat to my Vaillant ecotec plus 824 boiler. The hub, thermostat and receiver are all paired. The receiver clicks on when turning thermostat up or using via app on iPhone but the heating itself isn’t turning on. It’s like it’s not getting the signal from the receiver to switch on. See the attached photos. I’ve also tried with a link wire in between live and 1 on the back plate. The heating is turned on, on the boiler controls. Can someone please help