My boiler will light and stay lit for approx 30 minutes and then overheats, the lock out light comes on and the boiler needs to be left for about 15 minutes to cool then it will light again and run for about 20 minutes, then locks out again, I have replaced the stat and still have the same fault. Can anyone help?

Andy, December 2008

check pump works properly

sloppytom, December 2008