I'm in the middle of renovations, and my old Calais Marker radiant gas heater had to come out - and they can't put it back in - there was no flue kit.
A few years ago, I bought a Rinnai Slimline MkII - brand new, in its box. But no flue kit. It's been in storage since, waiting for this day to come. This was the last model that didn't require electric for ignition.

I can't source a flue kit, (they haven't been made for over 10 years now) or find anyone to respond to my request to make one for it.
I'm assuming a sheet metal worker could make one? It's to be flued through an old chimney cavity.

I really can't afford a new gas heater, and I hate wasting a perfectly good new one - just cos I can't source a part.

Any ideas out there?