combi boiler, trap not draining system?

As its a combi system, any radiator will do - suggest you take out the one you intend to work on.

John
July 2009

Try undoing the nut on the back of the drain cock if it has one, otherwise undo a nut on the valve on the lowest radiator in the system and have a couple of basins ready.

Ian
July 2009

have tried to unblock it but there seem to be something solid at the joint and i can't seem to shift it

gus
July 2009

Presumably you are referring to a drain down cock, the ones with the square nut end that you connect a hose pipe to? Its just full of gunge - undo the nut completely, poke something through and you'll get a flood - unless you have depressurised your system of course, in which case its normal!

John
July 2009