We have an older Heatilator wood burning fireplace that we want to convert to gas logs. The local Heatilator dealer told us this was OK and we could use the same chimney. Unfortunatley during last year's reroofing we tore out most of the chimney. I now need some straight sections of Mark 123 chimney, an elboe and a cap. Anybody know where I can find some? The OD is 14" and the ID is 8".