Viessmann sliding coupling telescopic extension

veissman_Bob

I'm looking the drawings for Viessmann's number 7424-107 sliding coupling / telescopic extension for medium sized Vitodens boilers and I'm unsure what the actual overall dimensions are.  From the drawings, it looks like it's two pieces of concentric vent pipe that slide within to adjust the overall length of the vent piece.  It's described in the Viessmann price book as being 1.25ft., but the rigid pipe venting system installation instructions showing dimension "g" as min. 11 inches to max 15.5 inches.  The problem though is that there's an additional section of pipe in the drawing that extends beyond the dimension "g".  Does anyone know if this truely is an adjustable lenght (no cutting involved) concentric vent piece and, if so, what the overall min and max dimensions are?  I'd think they are 11 to 15.5 but I'd like to be sure.

CMadatMe

You Must Have

An old manual because on page 17 of mine it cleary states that minor cutting is involved. The current manual is attached. That added piece of pipe is where the hub of the next piece would cover.

veissman_Bob

Thanks

Thanks!  I was hoping that the adjustment worked just like a telecope, i.e. that you could adjust it anywhere between 11 and 15.5 inches without any cutting.  If I have to cut anyhow, I'll just cut the existing piece of 0.5 meter concentric pipe that I have already.

veissman_Bob

Thanks

Thanks!  I was hoping that the adjustment worked just like a telecope, i.e. that you could adjust it anywhere between 11 and 15.5 inches without any cutting.  If I have to cut anyhow, I'll just cut the existing piece of 0.5 meter concentric pipe that I have already.