"David WE Roberts" wrote in message
...
Just had a visit from a very friendly plumber, about replacing an electric
hob with a gas hob.

In passing, he said that he had just had to condemn an installation where
a Polish person had connected the cold mains to the gas part of the
boiler, and the gas to the cold mains feed.
He had told them they would have to call in the gas and water boards and
it would const them £7-8K to sort it all out.

My mind is still mildly boggling over the concept.
[And the £7-8K; I suppose it depends on how long they had it all turned on
before they realised the boiler wasn't lighting and they seemed to have a
lot of air in the water system.]

I am also wondering which is going to cause more problems - mains pressure
water in the gas main or mains pressure gas in the water main.

Interesting comments.......

....now if you plumb the gas into the mains cold water feed to a combi I
presume you will have fun when you start bleeding the radiators?

Taking a long time for the water to come through, perhaps I've got time for
a fag.........

Agreed that if you do a simple cross over you are just likely to get water
out through the gas jets.

However you are likely to get gas throughout the central heating and hot
water supply as AFAIK this all flows through the boiler from the mains cold
feed.

This alone would presumably have the gas people round because a set of
radiators filled with gas is probably a minor safety hazard.

Yep - as described it shouldn't get back into the mains; it was just such a
graphic picture :-)

Cheers

Dave R