So for the past 3 years I’ve had little or no heating upstairs in my house. I have a dual system. Open fire and oil. Neither circulate hot water to radiators upstairs in either bedrooms even if I turn off all the rads downstairs it only warms a little. I had the whole system professionally power flushed and still no improvement. I’ve bled rads upstairs but no pressure at all when heating on!! Any advice much appreciated. I’m thinking of taking off the trv valves on rads upstairs to see if that helps.