boiler firing up for no reason!

[linedancer16]

I've just come home to find steam coming out of the boiler flue! The boiler was making a noise as though it was firing up but the heating wasnt on and no water - taps etc- was running. It stopped after about a minute. It has done this before but why?. Its a Worcester Bosch combi boiler, only 2 years old and working perfectly otherwise.

[factor-fiction]

When you say "boiler firing up for no reason!" do you mean it is turning itself on even though it should be off? Or do you mean when it's on it sounds as if it's firing up but never actually heats up anything.
If the latter, it happened to me and I was told it's quite a common problem, although maybe it usuualy happens to older boilers. I recall the plumber replaced a circuit board (didn't cost too much- I think he had a spare one in his van from another boiler), and ever since then ours has been fine.

[Old_Geezer]

I see they finally got Doc behind bars.

[linedancer16]

Morning! Thanks for the help. Its turning on for a short while when it should be off. The heating is off and no hot water was being drawn. Thanks for the explanation, doc, I think I understand! I have Homecare with British Gas so perhaps I should let them sort it out. I wasnt sure if it was a problem worth bothering with or even a problem at all! Thanks again.

[sidkid]

I have a similar issue. (no steam out of flue though) A friend who is a heating engineer says it is the pump turning itself on for a minute or so every day to move the water round the system....

[chakka35]

My Worcester occasionally switches on briefly when the central heating is off and when no-one is using the hot water. I have always assumed - possibly quite wrongly - that it is to keep a small reserve of hot water in the system.
Since the Worcester is renowed for being the best of its kind (successive British Gas engineers doing their annual inspections never stop singing its praises though they didn't install it!) it may be that I'm being too trusting.

[maclarencat]

I had an oil fired worcester bosch and it had a small hot water tank inside so you didnt get that having to run the water forever for it to heat up. The boiler would fire up to heat this to a constant temperature even when no heating was on or water running.