DO NOT USE his contactor. So could Lucky real name is (Sharanjeet singh multani) he is not corgi registered he use Virji Devshi Engineer platform. So called Lucky he came through my builder contactor. Lucky fitted all my underfloor heating & new boiler & part pipe work and left to builder to do all other pipes. but the job he done I have to call another engineer to fix my pipes & radiators & expansion bottle & drinking water filter which I was going to pay him for extra work. Main problem is you keep calling Lucky he is not reliable & i waited for him almost 2 month's he will never answer phone call , I lost my trust on him. Two engineer has ask me for floor heating diagram which I don't have. Don't let anyone do your GAS work if they are not corgi registered.