Update:
I called the client this morning with the additional info I gleaned from this thread. She said she had allready called British Gas and they were coming. I explained about combined feed/vents and that if BG charged her then I would pay her back.
They came out, two guys, a senior engineer and regular engineer. Found no fault but noted combined vent/feed and said that I was correct the second engineer must have cut it out to prevent the problem of air entering the system. They didn't charge my client. They then suggested that her plumber change the ball float valve!
I came over in the afternoon and changed the ball float valve free of charge.
So there you go. You live and learn. All credit to BG, they could have charged...and they had made the right call in the first place.
I called the client this morning with the additional info I gleaned from this thread. She said she had allready called British Gas and they were coming. I explained about combined feed/vents and that if BG charged her then I would pay her back.
They came out, two guys, a senior engineer and regular engineer. Found no fault but noted combined vent/feed and said that I was correct the second engineer must have cut it out to prevent the problem of air entering the system. They didn't charge my client. They then suggested that her plumber change the ball float valve!
I came over in the afternoon and changed the ball float valve free of charge.
So there you go. You live and learn. All credit to BG, they could have charged...and they had made the right call in the first place.