Hi, I recently to get an old fireplace up and running. It's a brick and
mortar fireplace with a newly installed gas log set in it. Prior to
installing the gas logs, I had the flue closed up to keep the cold air
out. Once I opened it, I got cold air coming into the house.

I'm a little concerned that the air is going in the wrong direction,
especially if it gets windy (we get a lot of strong wind in my area).
It doesn't seem like a strong draft, but it's enough to get me
concerned about the chimney not doing its job correctly.

I went on the roof and looked at the chimney. I noticed that there was
no cap on it, whereas just about every other chimney that I could see
from my roof had one.

I looked down the chimney, and it was clean. There's no cracks or
anything I could see in the chimney inside or outside the chimney
itself.

The chimney is on the side of the house where the roof is at its lowest
point. There is nothing blocking the chimney in the wind's path...no
rooftop, no trees, nothing.

My question is, should I install a cap on the chimney? I would think
this would do the job, but I would like to get some advice before I
tinker with something I don't know much about.

mike wrote:
Hi, I recently to get an old fireplace up and running. It's a brick and
mortar fireplace with a newly installed gas log set in it. Prior to
installing the gas logs, I had the flue closed up to keep the cold air
out. Once I opened it, I got cold air coming into the house.

I'm a little concerned that the air is going in the wrong direction,
especially if it gets windy (we get a lot of strong wind in my area).
It doesn't seem like a strong draft, but it's enough to get me
concerned about the chimney not doing its job correctly.
....
My question is, should I install a cap on the chimney? I would think
this would do the job, ...

Basically, it's not unusual for cold air to come down a chimney when
the damper is open and no fire is in the fireplace -- that and to
prevent losing warm air the other way is why dampers are there to begin
with.

Does the chimney draw when the fireplace is in use? If so, I'd not be
concerned. It's not possible to tell for sure, of course, whether the
situation is now different than before, but one possibility is if the
house is older and has been updated/remodeled that included
weatherizing so what used to draw well doesn't any longer. With air
tight houses, it's quite unremarkable that there isn't enough inleakage
to provide adequate draw. If you open a window a crack, does the
chimney then draw? If so, you've just demonstrated the above.

A cap _may_ help a little, it may not. Their primary function is
keeping the weather and birds/vermin out, with a corollary function of
some spark collection and draft control. I'd probably add one if you
plan on using the fireplace simply to avoid the swallows building nests
(as they do in mine every year and every year I say I'll fix it before
next spring and forget until they've already got the nests established.
Maybe w/ your post reminding me I'll get the lift out and get up there
and do something about it this year!)

mike wrote:
Hi, I recently to get an old fireplace up and running. It's a brick and
mortar fireplace with a newly installed gas log set in it. Prior to
installing the gas logs, I had the flue closed up to keep the cold air
out. Once I opened it, I got cold air coming into the house.

I'm a little concerned that the air is going in the wrong direction,
especially if it gets windy (we get a lot of strong wind in my area).
It doesn't seem like a strong draft, but it's enough to get me
concerned about the chimney not doing its job correctly.

I went on the roof and looked at the chimney. I noticed that there was
no cap on it, whereas just about every other chimney that I could see
from my roof had one.

I looked down the chimney, and it was clean. There's no cracks or
anything I could see in the chimney inside or outside the chimney
itself.

The chimney is on the side of the house where the roof is at its lowest
point. There is nothing blocking the chimney in the wind's path...no
rooftop, no trees, nothing.

My question is, should I install a cap on the chimney? I would think
this would do the job, but I would like to get some advice before I
tinker with something I don't know much about.

Cap won't help draft, but some sort of screen/damper could help keep
wild critters out. Raccoons have made it down chimneys.

Draft occurs when column of gas in flue is sufficiently lower in
density
(read: warm) compared to outside. What happened when you heated
the flue? How did you close/open the flue? Damper at throat, or up
top? (Note that closed damper is _good_thing_ when fire is out.)

Common causes of reversed draft:
negative gauge pressure in house caused by various discharges-
such as another fireplace, open attic window or exhaust fan;
chimney top too low for surroundings in wind.

Short chimney doesn't help, either.

You might consult a local expert, who can put eyes on it, and
suggest action.

J

"mike" wrote in message
My question is, should I install a cap on the chimney? I would think
this would do the job, but I would like to get some advice before I
tinker with something I don't know much about.


The first time you get a bird or a squirrel down the chimney you will have
the answer. It does not happen often, but it does happen. Be sure to get
one made from stainless steel. The painted ones will rust and stain the
chimney as it runs down.

"mike" wrote in message
oups.com...
Hi, I recently to get an old fireplace up and running. It's a brick and
mortar fireplace with a newly installed gas log set in it. Prior to
installing the gas logs, I had the flue closed up to keep the cold air
out. Once I opened it, I got cold air coming into the house.

Gas logs are nice.

You can usually operate the in a "ventless" mode. The ones I have are like
that.

IF your logs can be operated in "ventless" mode (i.e.: they shut off when
the O2 level falls and they tend to burn with grossly excess oxygen) then
there is little or no point in opening the flue.

If you want to flue to start "working" you have to get it warm/hot. That
means you operate you gas logs at maximum output and gradually open the
flue. When the flue "works" you are wasting most of the heat the gas logs
produce. Fireplaces aren't particularly efficient; they are just for looks
and feel. You get the same effect from the ventless logs.


You should get a CO detector (preferably "digital") just in case but Gas
Logs just don't put out ANY CO.

The main reasons for the cap is to keep critters and rain out. Some of
then can take on the extra job of completely closing the flue but you can
already do that by other means.

Not only do you need a cap but you should also cap the top of the top bricks
so moisture has less ability to soak them.



"mike" wrote in message
oups.com...
Hi, I recently to get an old fireplace up and running. It's a brick and
mortar fireplace with a newly installed gas log set in it. Prior to
installing the gas logs, I had the flue closed up to keep the cold air
out. Once I opened it, I got cold air coming into the house.

I'm a little concerned that the air is going in the wrong direction,
especially if it gets windy (we get a lot of strong wind in my area).
It doesn't seem like a strong draft, but it's enough to get me
concerned about the chimney not doing its job correctly.

I went on the roof and looked at the chimney. I noticed that there was
no cap on it, whereas just about every other chimney that I could see
from my roof had one.

I looked down the chimney, and it was clean. There's no cracks or
anything I could see in the chimney inside or outside the chimney
itself.

The chimney is on the side of the house where the roof is at its lowest
point. There is nothing blocking the chimney in the wind's path...no
rooftop, no trees, nothing.

My question is, should I install a cap on the chimney? I would think
this would do the job, but I would like to get some advice before I
tinker with something I don't know much about.

Art wrote:
Not only do you need a cap but you should also cap the top of the top bricks
so moisture has less ability to soak them.



"mike" wrote in message
oups.com...
Hi, I recently to get an old fireplace up and running. It's a brick and
mortar fireplace with a newly installed gas log set in it. Prior to
installing the gas logs, I had the flue closed up to keep the cold air
out. Once I opened it, I got cold air coming into the house.

I'm a little concerned that the air is going in the wrong direction,
especially if it gets windy (we get a lot of strong wind in my area).
It doesn't seem like a strong draft, but it's enough to get me
concerned about the chimney not doing its job correctly.

I went on the roof and looked at the chimney. I noticed that there was
no cap on it, whereas just about every other chimney that I could see
from my roof had one.

I looked down the chimney, and it was clean. There's no cracks or
anything I could see in the chimney inside or outside the chimney
itself.

The chimney is on the side of the house where the roof is at its lowest
point. There is nothing blocking the chimney in the wind's path...no
rooftop, no trees, nothing.

My question is, should I install a cap on the chimney? I would think
this would do the job, but I would like to get some advice before I
tinker with something I don't know much about.



A neighbor had a pair of Racoons come down the chimney. THey did a few
thousand dollars damage.

"John Gilmer" wrote in message
...

"mike" wrote in message
oups.com...
Hi, I recently to get an old fireplace up and running. It's a brick and
mortar fireplace with a newly installed gas log set in it. Prior to
installing the gas logs, I had the flue closed up to keep the cold air
out. Once I opened it, I got cold air coming into the house.

Gas logs are nice.

You can usually operate the in a "ventless" mode. The ones I have are
like
that.

IF your logs can be operated in "ventless" mode (i.e.: they shut off when
the O2 level falls and they tend to burn with grossly excess oxygen) then
there is little or no point in opening the flue.

If you want to flue to start "working" you have to get it warm/hot. That
means you operate you gas logs at maximum output and gradually open the
flue. When the flue "works" you are wasting most of the heat the gas
logs
produce. Fireplaces aren't particularly efficient; they are just for
looks
and feel. You get the same effect from the ventless logs.


You should get a CO detector (preferably "digital") just in case but Gas
Logs just don't put out ANY CO.

I would investigate this claim thoroughly before I trusted it.

Bob

I can't use ventless logs. I'm in California. I believe they are
illegal here.

My comments are in-line below:

dpb wrote:
Does the chimney draw when the fireplace is in use?

It looks like it does normally. I lit some newspaper to get a smoky
fire going and the smoke went up the chimney. This was when it was not
windy though. I will try that test again when the wind kicks up.

If so, I'd not be
concerned. It's not possible to tell for sure, of course, whether the
situation is now different than before, but one possibility is if the
house is older and has been updated/remodeled that included
weatherizing so what used to draw well doesn't any longer. With air
tight houses, it's quite unremarkable that there isn't enough inleakage
to provide adequate draw. If you open a window a crack, does the
chimney then draw? If so, you've just demonstrated the above.

The house was built in the 60's and has been through a few major
earthquakes, so it's definitely not airtight. It passed inspection when
I bought the house in 2000.

A cap _may_ help a little, it may not. Their primary function is
keeping the weather and birds/vermin out, with a corollary function of
some spark collection and draft control. I'd probably add one if you
plan on using the fireplace simply to avoid the swallows building nests
(as they do in mine every year and every year I say I'll fix it before
next spring and forget until they've already got the nests established.
Maybe w/ your post reminding me I'll get the lift out and get up there
and do something about it this year!)

I see. I haven't had a problem with pests getting in yet, but it's
probably a matter of time before they do. If it doesn't hurt, I'll
probably put a cap in, just for that reason alone.

There's mortor on top of the bricks. Does that help? From what I'm
hearing, it sounds like a cap is the way to go, but for different
reasons than what I was expecting.

In article .com, "mike" wrote:

My question is, should I install a cap on the chimney?

Yes. Here's why:

http://www.milmac.com/BlockedFlue.JPG


--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

My comments are in-line below:

Draft occurs when column of gas in flue is sufficiently lower in
density
(read: warm) compared to outside. What happened when you heated
the flue? How did you close/open the flue? Damper at throat, or up
top? (Note that closed damper is _good_thing_ when fire is out.)

A damper at the bottom (is that the throat?). It looks original, and
it's not airtight, but it certainly does a better job keeping the cold
air out when it is closed.


Common causes of reversed draft:
negative gauge pressure in house caused by various discharges-
such as another fireplace, open attic window or exhaust fan;
chimney top too low for surroundings in wind.

That's great to know! I have a whole house fan, but I only use it when
the flue is closed. The fan is great at demonstrating how non-airtight
my house is.

Short chimney doesn't help, either.

The chimney is about five feet taller than the point at the roof where
it is resides. It looks about as tall as all the others in a
neighborhood of tract housing.

You might consult a local expert, who can put eyes on it, and
suggest action.

The inspector didn't have a problem with it, and I do remember seeing
him measuring it (not sure why). I'm not sure if he would be considered
an expert on the matter.

That's a dream come true for my dog. A squirrel with no place to run.

"mike" wrote in message
oups.com...
I can't use ventless logs. I'm in California. I believe they are
illegal here.

That's too bad.

Nonetheless, they do work. Modern "ventless" heaters are quite safe.

But it still a "good idea" to get a CO detector.

You should get a CO detector (preferably "digital") just in case but Gas
Logs just don't put out ANY CO.

I would investigate this claim thoroughly before I trusted it.

Well, you can "investigate" all you want.

IF you use a ventless appliance (including a gas stove) then you should have
a CO detector. You will soon find, however, that you generate more CO by
burning dinner in an ELECTRIC oven than heating the whole house with
ventless heaters.

Gas burning appliances that are designed to be vented are also designed to
minimize the amount of hot gas that goes up the stack. Among other things
this means that the amount of air introduced to the gas is kept at a
minimum. A miscalculation means either excess heated air goes up the stack
or you generate the deadly CO.

But there is no reason not to permit a ventless burning all the air it could
posssibly use and then some. All the heat stays in the room. And that's
why ventless heaters are very safe regardless of what the authorities in
California think.

I would think they would work, but I don't want to get any problems
from inspectors.

I do have a CO detector on the opposite wall from the fireplace. I
might put some in near the bedrooms and near the garage.

"mike" wrote in message
oups.com...
I would think they would work, but I don't want to get any problems
from inspectors.

I do have a CO detector on the opposite wall from the fireplace. I
might put some in near the bedrooms and near the garage.

Once you have an approved installation, I just don't see how the
"inspectors" would know about your not opening the flue.

If you get at least one battery powered "digital" CO detector and move it
about the house you will discover where CO usually comes from.

Incense, for example, generates a good amount of CO. (Families have been
wiped out by bringing a charcoal grill into the garage.) Gas stoves
generate essentially no CO. But burning food on any kind of stove will
generate a reading. By a "reading" I mean something on the order of "10"
which is just on the range of detectability. With the exception of the
charcoal or coal burning the most likely source of deadly amount of CO come
from VENTED fuel burning appliances that have failed. Even then, it often
requires more than one failure mechanism: the burners are set too "lean"
AND something has permitted the combustion gasses to enter the living space.

(Some years ago I had a run in with some stupid women from the gas company.
They had turned off the gas for some outside repair work and I got lazy and
decided to let them re-light the pilot lights. Showing that a little
knowledge is a dangerous thing this silly woman stuck her CO detector in the
top vent of the water heater. All those gasses went up the stack. But she
read a 40 on her meter (which is low enough that had it filled the entire
house we likely would have had no ill effects) and she "red tagged" the
water heater. I took the tag off and complained to the gas company.
Never heard back.)

Bottom line is that VENTED appliances normally produce a small amount of CO.

mike wrote:
That's a dream come true for my dog. A squirrel with no place to run.


I agree that you should have a chimney cap, but that it's unlikely to
have much effect on cold air coming down the chimney. If it were me,
I'd have it rigged for ventless. And if you're worried about code,
just leave the damper in place, so it can still operate. I doubt
that violates any code.

If you leave a chimney open with no fire, your're going to be wasting
quite a bit of energy during cold weather.

The top brick should have a metal cap on it. Most don't and that is one
reason why people have chimney problems.



"mike" wrote in message
ups.com...
There's mortor on top of the bricks. Does that help? From what I'm
hearing, it sounds like a cap is the way to go, but for different
reasons than what I was expecting.

If your concern is that cold air comming down the fireplace chimney and
you need a cap anyway you may want to think about a lock-top chimney
top damper for around $550 installed. Or if you are just wanting to
insulate your damper and help it do its job better look into a chimney
balloon for $40.
Either will help you limit the cold air infiltration and I have seen
some people use both.

A stainles cap would be good for keeping the weather elements and
vermin out, but wont help you with cold air infilttration.

mike wrote:
Hi, I recently to get an old fireplace up and running. It's a brick
and mortar fireplace with a newly installed gas log set in it. Prior
to installing the gas logs, I had the flue closed up to keep the cold
air out. Once I opened it, I got cold air coming into the house.

Here's another reason:

"[A] squirrel fell down a chimney at a Two Rivers home and landed in a fire
in a fireplace Monday night...The squirrel escaped the fire and ran around
the house..."

http://www.chron.com/disp/story.mpl/...e/4367215.html

On 28 Nov 2006 09:03:46 -0800, "mike" wrote:

Hi, I recently to get an old fireplace up and running. It's a brick and
mortar fireplace with a newly installed gas log set in it. Prior to
installing the gas logs, I had the flue closed up to keep the cold air
out. Once I opened it, I got cold air coming into the house.

I'm a little concerned that the air is going in the wrong direction,
especially if it gets windy (we get a lot of strong wind in my area).
It doesn't seem like a strong draft, but it's enough to get me
concerned about the chimney not doing its job correctly.

I went on the roof and looked at the chimney. I noticed that there was
no cap on it, whereas just about every other chimney that I could see
from my roof had one.

I looked down the chimney, and it was clean. There's no cracks or
anything I could see in the chimney inside or outside the chimney
itself.

The chimney is on the side of the house where the roof is at its lowest
point. There is nothing blocking the chimney in the wind's path...no
rooftop, no trees, nothing.

My question is, should I install a cap on the chimney? I would think
this would do the job, but I would like to get some advice before I
tinker with something I don't know much about.


IMHO:

First chapping off the flue against rain and animals just sounds like
common sense.

Second, your symptoms sound like there is something else. If you even
suspect exhaust gasses will be entering your house, instead of
leaving, it doesn't sound safe to use your gas fireplace. Have a
professional check out what could be causing the reverse drafting
issues.

Good luck,

tom @ www.Consolidated-Loans.info