Air lock ?

[Paul C]

Hi I drained vented system down to replace a rad now filled up and bled pump and rads. Boiler ( oil) fires up and the central heating outlet is cold & pump is running. The feed pipe to the hot water tank is scalding hot but then no water is getting to the storage tank. This water is so hot it then turn the boiler off so my central heating is cold. Do I need to drain down again will this help? How do I fill up again and stop this happening ?

 

[joni os]

Circulation problem. Check for any vent points on flow and return that need manual opening. Manually open motorised valves and ensure pump is rotating.