Hawk II combi no Heating

I have an aging ferroli Hawk II combi boiler and it has developed a
fault. It had a loss of pressure, which it often does, but now I have
refilled it no heating. The hot water is OK and the Pump is working
but all that happens for heating is that the boiler fires for approx
30 seconds then goes off for 10 minutes and then repeats. The
radiators are very slightly warm. Any help and ideas would be
Reply to
Pump problem (despite what you say). Air locks. detached impellor. Temperature sensor.
Main flow/return isolator(s) closed.
See SealedCH FAQ about the pressure.
Reply to
Ed Sirett
know why. The day before I undid the screw on the outside of the pump and I can hear the pump stop, if i push in the hole with a screwdriver it starts. Bleed the heat exchanger and found no air. If I listen at the rads I can hear the pump pushing water so if it is the pump what else can I do to confirm this. The mother board has diagnostic LEDs to show whats going on and when working and power applied some should light, however I have never seen any of them lite. Checked temp sensor and 1K which corresponds to cold water in Rads, CH overheat thermostate closed. I think it could well have needed venting, which I did but never found any air. Just hope it keeps going Thanks
Reply to
I think I will try and replace the pressure release vent valve which is causing the loss of pressure, how easy is it to replace. Thanks
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