Airlock problem and boiler won't light after draining

[KevinBarnes]

I have 2 problems but the 1st is this: I have drained a few litres or so of water from my heating system after putting cleaner in it via the feed tank which is high in a cupboard upsatirs in our bedroom. (says to leave it in for 4 weeks) but now there seems to be an airlock - i presume this as the boiler won't start now. the pilot went out and won't restart. is this because i drained water out and air got in through the feed tank? or is it a coincidence that the boiler won't start? wjat can i do please

 

[jacobball]

I had an airlock in my heating pipework before - in my old house. I had to close all the radiator trv or manual valves fully off, set the pump speed to maximum and force the air out one by one. But you have no boiler working, so you may need to try a different method known as backfill...