I had a high efficiency gas furnace installed. Originally the contractor said he would run the vent through the old chimney but his installer just ran them out the side of the house because there is a bend in the chimney. The side vents are pretty obtrusive. Is it possible to use ABS pipe for venting since that would be flexible enough to get it around the jog in the chimney?
Hi John, some of the ABS pipes are approved for the high efficiency furnace venting. You can find details here High Efficiency Furnace Plastic Vent Pipe Types. But I’m not sure if it will be possible to make it through the chimney offset.
The problem is, that ABS, CPVC and PVC pipes crack easily when under stress and in cold temperatures. If you force it into the chimney offset, it might just fall apart during the winter. Also, just in case you’re still using that chimney for some other appliance venting, you can’t put any plastic pipe there.
Some jurisdictions and / or manufacturers might permit it only if the plastic pipe is within the stainless steel pipe – check your local code and manufacturers requirement. You can also consider using
Bayvent200 or Bayiar30aventa exterior plate for your furnace venting purposes – it doesn’t look bad on a side wall and it will be much cheaper / easier to install it (if your particular furnace brand and local code allows it)