phaeton wrote:
Lately I've been noticing a specific smell in the house. It's
something I've smelled before in other houses I've visited or lived in
with gas appliances (heat or otherwise). I'm going to guess that it is
a "burned gas smell". It smells faintly like unburned gas and
something else, like 'heat' i guess, even sometimes a little bit like
kitty litter. I know that's a bit silly, but I can't think of anything
else that smells similar, and on top of that my nose doesn't work so
well anyways. In fact, the Missus says she can't smell what I'm
talkinga bout at all.

We have a 2-story house w/ no basement. There is a gas boiler and a
gas water heater on the first floor under the stairwell, behind some
vented doors. They both vent into the same chimney via a Y-pipe. It
is passive- i.e. no fans, turbines etc to blow the exhaust out- just
heat and gravity. The space that these are in is definately where the
smell is coming from, and AFAICT it's the boiler that's doing it.
SNIP

As mentioned, you can ask the utility to come out and check.
They are usually very good about that and can be helpful.
Understand that if there is something suspicious, they
may red-tag it.

Besides the well-known odorant they deliberately put in
the gas, there is the possibility of odors from
"aromatic hydrocarbons" present in the gas. This is
a very odd smell which defies description. It is
almost always produced because of improper/incomplete
combustion which can be due to a fault in the burner
or insufficient draft. This has nothing to do with CO
and instruments may not show excess CO (which you can't
smell anyway).

The "bad odor" CAN be a warning though and shouldn't be
dismissed lightly.

Jim