Last spring we changed over from an oil furnace to high efficiency
natural gas. The contractor who did the job put a metal cap over the
opening where the oil furnace chimney entered the masonry exterior
chimney and it is now completely unused. The top of the chimney is
still open; should it also be sealed close?

Probably best bet before some bats or birds decide to nest in it are you
sure it is not used? Where did he vent the gas furnace?

Wayne

"mike" wrote in message
oups.com...
Last spring we changed over from an oil furnace to high efficiency
natural gas. The contractor who did the job put a metal cap over the
opening where the oil furnace chimney entered the masonry exterior
chimney and it is now completely unused. The top of the chimney is
still open; should it also be sealed close?

Wayne is on the right track.
There is water penetration and cold air to consider as well.
TB

The furnace is vented directly through the wall using plastic vent and
exhaust pipes. Guess I'll cap it next spring when things warm up!

wayne wrote:
Probably best bet before some bats or birds decide to nest in it are
you
sure it is not used? Where did he vent the gas furnace?

Wayne

"mike" wrote in message
oups.com...
Last spring we changed over from an oil furnace to high efficiency
natural gas. The contractor who did the job put a metal cap over
the
opening where the oil furnace chimney entered the masonry exterior
chimney and it is now completely unused. The top of the chimney is
still open; should it also be sealed close?

What about hot water? Does it still vent thru the chimney?

"mike" wrote in message
oups.com...
The furnace is vented directly through the wall using plastic vent and
exhaust pipes. Guess I'll cap it next spring when things warm up!

wayne wrote:
Probably best bet before some bats or birds decide to nest in it are
you
sure it is not used? Where did he vent the gas furnace?

Wayne

"mike" wrote in message
oups.com...
Last spring we changed over from an oil furnace to high efficiency
natural gas. The contractor who did the job put a metal cap over
the
opening where the oil furnace chimney entered the masonry exterior
chimney and it is now completely unused. The top of the chimney is
still open; should it also be sealed close?

"mike" wrote in message
oups.com...
| Last spring we changed over from an oil furnace to high
efficiency
| natural gas. The contractor who did the job put a metal cap
over the
| opening where the oil furnace chimney entered the masonry
exterior
| chimney and it is now completely unused. The top of the chimney
is
| still open; should it also be sealed close?
|

Not "sealed" ait tight, but closed off with a fairly fine mesh or
something similar that's permanent in nature. They make covers
for that purpose. Don't seal it or you may end up with crumbling
problems with it. And, be positive nothing else vents into it on
its way to the roof!

Pop

It'll stop rain from entering.

mike wrote in message
oups.com...
Last spring we changed over from an oil furnace to high efficiency
natural gas. The contractor who did the job put a metal cap over the
opening where the oil furnace chimney entered the masonry exterior
chimney and it is now completely unused. The top of the chimney is
still open; should it also be sealed close?