CH leaves upstairs hot, downstairs cold until I hit HW
Complete n00b here.
I have a two region OFCH system with thermostats up and downstairs.
When I turn on CH only upstairs radiators heat, even when both thermostats are set to max.
Then when I turn on HW at same time and CH the downstairs radiators fill and get warm.
Thermostats issue? Or motorised valve issue?
Thanks