after having a service on boiler it started making a tapping noise after being on for a few minutes then it goes away but does it every time the boiler comes on the man who serviced it said the pressure was low and he had sorted it. After leaving i noticed pressure was still low, my son tried to pressure it and nothing happens, i am neither losing or gaining pressure it i had a tapping noise on one radiator before i had it serviced, that has now stopped but as i say boiler is tapping but running well help

jean, April 2012

Try bleeding radiators to get rid of air, Then with system cold try to increase pressure, you should hear the water going in, same as you do running a tap or after flushing the toilet. Might take a minute to start to increase, If not and pressure does not increase, could be a valve problem, with the fill loop. close it off, disconnect from boiler end, should be a valve/one way fitting to stop any water coming out of system. then open the valve to a bucket or something, see if you get water out, if not valve fault or 1 way fault or some other valve. Pressure to about 1 bar COLD

SD, April 2012