My Vokera Vision boiler (enclosed system not combi) heats the water up fine (pump and outflow valve get hot) but does not circulate it more than a few inches along the outflow pipe. New pump and new Auto Vent have had no effect. I have manually bled the system of air at the top of the boiler . I have cleaned the TF1 filter outside the boiler so that cannot be causing an obstruction. The new pump (and in fact the old pump) both seem to run fine (light is on and whirring can be felt). There are no error codes. I am wondering if the stop cock valves below the boiler could be faulty as they both drip a bit and the inflow return valve on the left seems to turn without any resistance at all inside. They are definitely in the correct On position. Any thoughts? Could drain boiler again and check if water moving through valves by cracking off boiler-side nuts and turning valves on and off. With dripping I need anyway to replace them - the outflow valve easily because the outflow pipe can be blocked off at the TF1 filter, but the inflow return valve cannot be blocked off easily so I was thinking maybe I could lower the pressure of the whole system to 0 and then change the inflow valve while an assistant blocks off the water from the inflow pipe with thumb and plenty of towels and bucket....
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