DIYbanter - Help - I have a back boiler and want a combi boiler fitted but have plastic pipes!

Hi

I hope someone can advise me here as I am totally clueless!

We moved into our house about a year ago and inherited a baxi back boiler and central heating system. We have decided to change the system and have a combi boiler fitted and this will allow us to have a new inset fire and get rid of the not so nice one that we have at the moment.

We have had BG out who have given us a quote which we are happy with and they sent their surveyor out yesterday to measure up. It was all booked in for next week but as the surveyor was leaving he noticed that all our pipework is plastic. They are now saying that they can't instal a combi and we can only have a normal boiler. We don't want a normal boiler as we want to get rid of the water tanks in the loft. My husband has spoken to some of his friends and they have combi boilers with plastic pipes and can't see what the problem is. We have pulled up the floor boards so that we can see the pipes and they have written on them "12 bar/12c 7 bar/82c HBPUK PB" and we have been told that this is more than okay for what we need.

Is the fact that we have plastic pipes a problem or not? If we get a local plumber out to do it will it be okay or will it start leaking? Is there anyway around the problem other than changing all the pipework?

Yours hopefully

Vikki