isolating radiators

[donr]

i keep losing pressure from my worcester 240 combi and i want to confirm that it is not a leaking pipe under the floorboards i looked at the pipework coming out of the bottom of the boiler and 2 of the big pipes have screws in them . do i just have to close these screws?
i have also just seen that a constant drip is coming from the overflow type pipe outside

 

[chrishutt]

Probably, but some isolating valves are prone to leak, particularly the "screw" type. You take the risk, but before you do, check the discharge pipe from the Pressure Relief Valve, the auto air vent in the boiler and the spindles of all radiator valves.