We have a problem with the central heating taking a lot longer to heat the house, compared with last winter. As far as I know nothing has changed, such as pump speed. The radiators do all get hot eventually (after a couple of hours), so I don't think the radiators need bleeding. They are just luke warm for ages. The pump is quite new ( a year or two) . The timer has been a bit erratic recently - we have had to reset it after power cuts but apart from that nothing has changed.
Any ideas?
Thanks