I have oil fired CH. Following a power cut, when the power came back on, the timer switch for the boiler did not. Power is still getting to the timer because it's displaying odd characters but no matter what buttons I press, it will not come back on. (I've had a few power cuts before, but this has never happened.) I managed to turn the boiler on its main switch once, but have not been able to since. Is the problem likely to be just that the timer needs replacing or have I now broken the boiler as well? (sorry - I obviously know nothing about this sort of thing !). If it's just the timer, are they easy to replace, or should I get a plumber out to service the whole thing?!