thanks for your replies , but I would just like to make sure we are talking about the same thing - I am afraid I am the stereotype woman on her own, not got a clue. It is a potterton suprima 30 boiler with a danfoss timer in the kitchen - there is a water tank in my bedroom cupboard, which has a few electric bits on it, then there is a big lagged thing in the attic which I think is the water tank? - the thing that needs repairing was upstairs somewhere - the boiler will usually light in the mornings if you put the water on and stays on for less than an hour - you can put on water only but not heating only. It will then not light again until maybe 12 or 15 hours later - even if you run the hot water for a dishwash and washing machin, it still does not light until later so it does not seem to come back on just when the water needs heating, which would have seemed logical - instead it just come on if it feels like it !! when it does fire up the green light comes on on the boiler, but otherwise it is red - if you try that reset button thing the green and red light are on at the same time, then the green just goes out after maybe 3 seconds and the boiler does not do anything. -- so, does it definitely sound like does need a new 3 port zone valve as they say or could it be something else, and is there a circumstance where it might cost what they are asking or is it a rip-off for sur, and if it is can I report them to anyone for trying to scam me? - I live in lytham st annes if anyone can recommend anyone in this area - thanks -Bernadette