No pressure indicated on gauge and yet Radiators appear to be heating ok. Switching on Hot water Tap brings on Flame light, but goes out. Hot water supplied briefly, after usual delay but then goes cold. Have tried to refil the system using the two Taps, but nothing happens. Have done this sucessfully in the past. That time, I could hear the water re-charging the system. Not aware of any leaks in system. Could this be a faulty Tap or a valve elsewhere in the heat exchanger circuit? Has anybody else out there experienced this fault? Any help on this matter would be greatly appreciated as this is for my Mother who is a poor pensioner...

DewTcalls, December 2007

Further developments to question above:
I have checked that water is flowing through inlet tap, One way valve and Tap connecting to Central heating return and found to be ok. The second Tap connects to the "Central heating return valve". Is this one way? If so, I assume the water passes through the Main heat exchanger then out of the CH flow service valve? What is the function of the "Automatic bypass valve" on the linking tube between CH Out and CH in?

DewTcalls, December 2007