Mikepier wrote the following:
I have a 6 month old Sears (AO Smith) 50 Gal gas water heater. While
in my basement the other day, I noticed the plastic red " HOT" and
blue "COLD" rings around the heat trap nipples were melted around the
area where the exhaust flue pipe is.
So I raised the T-stat to fire up the water heater to test, but found
no excessive heat around the exhaust and draft hood. Testing with a
match confirmed the draft was good. By the way, the exhaust pipe is 3"
rigid duct. The specs to the water heater allows 3" or 4" ducting. I
took apart the duct to check for blockage, and it looked clear.
Now last night I was in my basement again, and this time I noticed
excessive heat around the draft hood, So much that I could not keep my
hand there for that long. When I did the draft test with a match, the
flame was blown out. I turned off the water heater and tested again
with the match, and the flame was still blown out.
I also tested it with my furnace vent without the furnace running, and
that was blown out too.
The only thing I can think of is that it was very humid outside last
night and the air was still, possibly causing no updraft.
I rechecked about an hour later, and the draft was good. What could
cause this?


If it's any comfort to you, I have a 5 year old GE propane water heater,
and the red and blue plastic surrounds of the hot and cold pipes are
warped from heat. I also have black foam pipe insulation around the hot
pipe to reduce heat loss until it leaves the basement. It too, is
slightly melted at the bottom.
Maybe it's due to blow-by during windy conditions when the heater is
heating the water.
I'm not going to worry about it unless water starts squirting from the
heater around the pipes. My office and shop are here in the basement, so
I'll know when that happens.
Maybe some metal sheeting on the sides of the flue next to the pipes
will prevent further melting.



--

Bill
In Hamptonburgh, NY
In the original Orange County. Est. 1683
To email, remove the double zeroes after @