Tom and hk,

Finally got a chance to review the A O Smith owner's manual.
Designation on front of manual is:
FPSH/FPCR/FPST with Smart Valve & 2" PVC Vent Capability

Under Installation of Vent System it says in part:"Nonmetallic vent piping may be used if it has a HDT (Heat Deflection Temperature) of at least 157 degrees F. Some typical nonmetallic vent materials meeting this requirement are PVC to ASTM D2665... " (and others listed).

The sch 40 pvc that was used shows that ASTM 2665 designation stamped on it, so it appears that the installer used one of the allowed materials. They just didn't secure it to the heater properly.

Thanks to both of you for the information.

Please let us know what you find out. If what you have for a vent pipe is schedule #40 PCV I would have it replaced at once. Good luck, Tom

Tom
I think Smearcase is saying the Sch 40 meets the specs of the installation instructions.

Yes. That is what I got out of it.