As it is getting cold I have started faffing around with my gas heating system. Every year it is the same old story - it never bloody works first go! Anyway there is what I presume to be a ball valve with a tap near my heater unit. The tap goes from inline with the pipe to 90 degres across the pipe. Is there any standard to gas taps that would indicate which way is open and which is closed (no markings on the tap)? I am assuming that inline with the pipe is open but as my heater unit is a tempremental old bugger I can never be sure if it doesn't work because it is crap or because the tap is off! I end up having it half way to be certain but would love to know which is which.