Ross Kirkland
If it makes a kettling or bubbling noise before cutting out, it may be air blocked which is causing overheat/thermal safety device to trip. Turn heat output down to lowest setting & if competent at DIY, purge air from circulating pump & radiators, please only do this when system is cold. Top up system as required. Switch boiler on low heat, leave for 20 mins and if it hasn't cut off, turn the heat up. A plumber or heating engineer may be required if this does not remedy!
