Hive - Boiler only fires for water

I recently installed a hive dual thermostat to work alongside my Worcester Greenstar 34Cdi classic. The water side of things works perfectly. Boiler fires up, hey presto. The heating however does not fire the boiler. The heating only works if the water is on as well. Anyone got any ideas. Please help.

 

You don't give us much to go on there. Is that how it always worked before the Hive was installed, or could you have the central heating on without the hot water being on at the same time?

What type of system do you have?

eg:
Fully pumped with a two 2-port motorised valves
Fully pumped with a 3-port motorised valve
Gravity circulated hot water and only pumped central heating
Something else?

 

I have seen that with 3 port Y Plan when the micro switch inside valve had failed and latching the valve open kept it going, but in summer radiators got warm when calling for domestic hot water, but worth a try for a quick fix.