Since my roof was refelted - some crap got into the water tank (which is on the roof). As a result the hot water has limited flow which I assume is a blockage. However more worringly is the loud banging pipes usually after flushing the loo. It has always banged but seems much louder now (there is one new significant bang in the HW heater area about 3 mins afte flushing) and can intermitently do this every few minutes for a few hours after in one particulasr area below the bath which is where the pipes lead to the loo (although it becomes a lot quieter). I thought it was a drip sound from below at first but now am thinking it the pipes banging. Could a blockage cause this - and would getting someone to drain the sytem solve both the hot water flow and the banging?
