Gas fire backboiler change

I have just had my old gas fire and backboiler taken out, I want to put in another gas fire. There is a hole in the wall and a 5 inch cortex flue liner. I have had a couple of plumbers round and been to BQ home base and local gas fire. No one seems to say the same thing. BQ and homebase wouldnt make any comment about suitability to put in fire. One plumber said the lining would have to come out another said get a gas fire that will join onto the flue liner and its fine. Can you get a gas fire that will fit onto a 5inch flue liner . No retailers seem to know? Is that the only way I dont really want to have to pay someone to get on the roof and pull out the flue liner. Thanks folks Rich Westerly 2219 DAVICO

Different models and type of gas fire require different types of flueing arrangements. Some permit this or that others forbid that or this etc.etc.

An unlined 225mm square chimney with a suitable terminal seems to be OK with the majority of types and models.

As you say the retailers don't know and the only way is to read the install instructions (which they may be reluctant to extract). The manufacturers should help.

The other week I "labelled" a fire which some "illiterato" had fitted to a fireplace with a liner and a flue gas collector box. As well as the instructions explicitly forbidding this arrangement, the flue refused to draw even after the the full 15 mins warm up time.

Another point to consider is that the nominal (if not the actual) life of the liner has now expired as it has had its service lifetime with the boiler. Even if you find a fire which is designed to work with a liner you would still be advised to remove/replace it.

Against this background all the advice you were given wasn't far off the truth.