The first Glow worms only had one valve. It was on the gas.You think it's capped off? You are wrong. That is an integral part of the valve.The valve is not for the filling loop, its the flow out of the boiler. Dont switch off unless you want to drain boiler and then switch off both flow and return.could be just one of these you need http://www.amazon.co.uk/Plumb-Pak-Compression-Blanking-Nut-4in/dp/B0039823M8 but when you get a leak always check to see if there's a leak further up that's dripping down, the valve is for the filling loop and the valve has been left open,turn the black knob to the right a quarter turn to switch it off
Interested to know how she get's any heating with the flow capped off then ??
the flow goes through the wall like the first gloworms they brought out ?
Jeff[/QUOTE
must have been an earlier model then than the ones I fitted in the early eighties,they had back entry valves which was easy to fit if you went through the wall with the pipes,but our company wouldn't supply street elbows if we had to drop the pipes, so we had to solder out of position otherwise the nuts on the valve would solder as well,though not to difficult as there was a jig