After replacing a seal on radiator fitting , and system now sealed, I have noticed that the outside drain plug is leaking
What effect will this have on the system (if any),pressure on boiler is steady at 1.5 bar

Hi Carrie

You'll lose pressure over time as you suspected. Purchase a BOILER DRAIN CAP and cap the threaded drain... should resolve the issue for you... ;)

Mark

Can you be more specific about what is leaking, outside drain plug is just to vague for me. If it is indeed a boiler drain, do as Mark suggested, but I fear it may be a pressure relief drop tube that is leaking?