my boiler let me run hot water off for awhile then it would go on lock out and red light come on, press to reset then sometimes it would run for longer or shorter periods, plumber came ,said hed cranked up air pressure switch in which it ran fine for couple of weeks, now same problem again, also same when heating is on , runs awhile then locks out. Plumber said get new a p switch , i fitted new one correctly but when re assembled it would not fire up, it went through the lighting sequence but would not light . I would appreciate any ideas .Thanks

Richard, September 2007

The problem is likely to be associated with the fan/venturi however because these are the province of a CORGI professional I cannot give you detailed instructions.

The "plumber" you had was evidently not very familiar with boilers but then we hear that very often!

Tony

Tony Glazier, October 2007

It can also be the venturi fan - try spinning the fan by hand, if it feels heavy, spray some WD40 or better still take out the venturi and clean the whole fitting

karamat, October 2007