HP DesignJet T120

I have a DesignJet T120 24 inch plotter which prints A1 and A2 from roll feed and A3 and A4 from a sheet feeder. The sheet feeder holds the A3 cut sheets in Portrait orientation. When printing A3 drawings within ZW3D, I cannot get any combination of drawing alignment, paper alignment or image rotation to print, the printer always thinks ZW3D is calling for 420 wide paper - A3 Landscape - when it only has 295 wide paper in the sheet feeder. To print A3 drawings, I have to export to PDF then print the PDF which prints as A3 Landscape rotated 90 deg.
There is no problem with A2 drawings which can be aligned any way on the roll feed paper and A1 prints OK rotated 90 deg.
Does anybody else have experience with this plotter? It is not a big issue as exporting to PDF does not take long but…