Boiler pilot comes on then goes out

Just had a new bathroom fitted and now the boiler won't fully light. Its a Valiant and always extremely reliable. Pilot lights but then goes out. I
Is this a pressure issue or air in the system? If so, how do I re-set pressure / get air out of the system?
(not calling back the Cowboy plumber! and I really would like a hot shower!)

You have not mentioned the model of boiler!

If you have topped up the pressure to about 1.5 Bar then its unlikely that there will be anything else you can do yourself.

I would suggest you engage a competent boiler engineer. Its unlikely your cowboy plumber was CORGI registered to work on gas appliances.

Tony Glazier

Problem solved once I learn't about the filling loop and how to re-set the pressure. Thanks