I am using a Hive multi zone system with 2 thermostats (one for upstairs radiator and one for downstairs underfoot heating)
The downstairs heating was not coming on so I had a look at the Grasslin 2 port actuator and it appeared the motor had gone. I replaced the actuator which now works. It opens the valve which turns on the boiler pump but there is no call for flame. The other thermostat works fine and both are wired up identically. The downstairs will only heat up if the upstairs is calling for flame. Any ideas.
Regards