After flooding, I replaced my radiators downstairs with underfloor heating (as part of raising the floor level etc) The underfloor heating works well, but the radiator system upstairs now emits a bang (with vibration in the pipes, if you are touching them when it happens) about 40 mins after the clock tells the upstairs system to start. Occasioanally it bangs again, later on, but always the once. It is not possible to say exactly where the noise comes from. There are now 6 rads upstairs, 4 of them usually in use.
I have an additional pump for the underfloor heating, and a Honeywell valve to isolate the upstairs system when it is not being called for by the clock.
Any ideas :?:
