I was thinking that from the start, but you will need a gas engineer to come and purge it for you and to check it's gas tight after.
I've had a few before when pilots been turned out and after being re-lit a week or so after, the air has caused it to not light immediately, so again the pipework/system needed purging
I've had a few before when pilots been turned out and after being re-lit a week or so after, the air has caused it to not light immediately, so again the pipework/system needed purging
