securing telescoping double wall stove pipe

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ramack

New Member
Jul 28, 2011
17
CO
I have a MetalFab telescoping double wall stove pipe attached directly to the top of my stove. It's fastened to the stove top flange on the bottom and a 90 degree elbow on the top. When the pipe cools it contracts and decreases in length and puts pressure on the various connections leading up to the ceiling support. Are the two sections of the telescoping pipe supposed to be fastened to each other? The instructions don't mention fastening other than the ends of the pipe assembly.
 
I put three 1/2 inch self hex tapping screws at every connection and seams.
 
MetalFab's double-wall installation instructions only show screwing at the joints, not at the telescoping section overlap.
http://www.mtlfab.com/media/L801.pdf

Selkirk however, recommends screwing the telescoping section overlap of their DSP connector pipe together, as does DuraVent for their DVL connector pipe.
 
I was think of pre-drilling holes for 1/4 long sheet metal screws at the overlap to prevent slippage.

Rich
 
That should work well. I ran into a problem with the screws not being long enough at the ceiling connection due to the retaining ring. But everywhere else 1/4" should work well.
 
Mine is screwed top and bottom. At the slip joint though it had a tiny bit of gap and it would suck in a flame from my butane lighter so I worked a little stove cement into the joint.
 
metal said:
No, the two sections of the telescoping length are not supposed to be fastened together. This allows the pipe to expand/contract. You should ensure that you have a minimum of 2" of overlap though.

Duravent says to secure theirs with the DVL double wall, that's how I did mine and it's fine.
 
metal said:
No, the two sections of the telescoping length are not supposed to be fastened together. This allows the pipe to expand/contract. You should ensure that you have a minimum of 2" of overlap though.

That's not generally true. I use duravent double wall and the telescoping section is fixed with screws. Nomatter what you do, the pipe system expands a bit.
 
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