Our new house was
built with a high efficiency furnace and hot water heater. Both were vented
with 2" PVC pipe. Unfortunately the pipes were hung with
"normal" drain-waste-vent (DWV) "J hooks" like the ones you
find at the "big box" stores. These hangers were not intended for use
with venting systems that see large temperature swings. Consequently the
hanger/pipe connections make a lot of noise as the pipes heat up and then cool
off. The hangers are attached to the
joists of the floor above which makes the house structure a "sounding
board" for the connection noise. I even contacted the manufacturer of our
original "J hooks" and they said their product was not approved for
this use!
Fortunately there is
a good answer if you still have physical access to the "J hooks".
Warwick Hanger makes a great "J hook" with a hinged top piece so that
they are not "spring loaded" around the PVC pipe. It's called the "Glide
Lock J Hook" . I purchased a box of these and then lined most of the
surface of the "J hook" that touches the PVC pipe with self-adhesive
felt. Then I replaced all of the "normal J hooks" with the new ones.
And that is the end of the noisy PVC vent pipes.
