Thread: Armstrong oil furnace questions

Armstrong oil fired furnace manufactured in 2000. I looked in the burn chamber and the white refractory material did not rise up high enough to prevent the flame from contacting the metal. The material had a clean edge and didn't look deteriorated (although the viewing was limited).

Is this typical or is it likely that the refractory material has fallen down or deteriorated? I couldn't get a picture due to the small opening.

Also, in the attached picture is the presence of soot at the left opening an indication of a specific problem? Do these openings have a technical name?

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John, that thing is full of soot and should be cleaned and serviced.
Did you feel back pressure when you opened the viewport to the burn chamber? That's what I call them.
The firebox insert should cover all areas where directly hit by the flame.
at 10 years old it's possible the liner was replaced and was the wrong size but from the soot buildup it looks like it hasn't been serviced in a while.
Were there tags on the unit indicating last service?

Wayne,
I did not notice any back pressure at the view port.
There were no service records on the unit.
The top of the burner had a white sticker with a date of Jan. 2010 on it. I assumed that the burner was replaced.
That is a good call on the wrong size replacement material. That is very possible.

The heat exchanger cleanout ports are full of either soot, or rust, or both. Chamber refractory in these furnaces are formed and should be in one piece. A complete service and cleaning of this furnace is warranted.

I'll echo David and add that if the combustion chamber is full of crud, so is the chimney. Sweep and Level II in addition to cleaning this pig out then diagnosing and correcting it.

I'd refer to those as 'inspection ports'.

Once the Creeping Crud starts, it builds rather rapidly. Could be many things so no use speculating until both appliance and chimney have been thoroughly cleaned, thoroughly inspected then tested to find the problem.

Note the soot stains around the appliance vent collar, too. I'll bet there are more at the chimney connector joints and barometric damper.

Originally Posted by Bob Harper

Note the soot stains around the appliance vent collar, too. I'll bet there are more at the chimney connector joints and barometric damper.

Yes, more soot stains and the barometric damper is actually improper as it is only able to move about 1/4 to 1/2" or so. I wonder if that is what is causing the problems.

Often a technician will deliberately defeat a baro. damper when they have poor/ inadequate chimney issues. I find them all the time and invariably the chimney is blocked, oversized, cold, very tortuous, short, gunked up or all the above. Closing the damper drives the stack temp. up in an effort to increase draft. I find them cemented closed with furnace cement. Should be a Red Flag of deeper issues.

Now, many, many baro. damper's valve plates will jam simply from heat distortion or rust. Another problem is where the installer runs a screw from the 6 O'clock position blocking the valve plate's swing.

If the unit is fired with the baro. damper closed resulting in high draft, it can lead to overfiring, soot and carbon monoxide formation along with a drop in efficiency. It's there for a reason and by code unless expressly prohibited by the mfrs. instructions.

HTH,

Bob,
That is starting to make more sense then.

See the pictures of the soot, the damper (note the left side restricting device), and the last is a picture looking up the flue from the cleanout.

Thank you for the info.

Unfortunately, there are installers that don't bother to set up these burners. These furnaces are able to fire at up to three different rates and normally come from the factory set at the highest rate with the largest nozzle. Furnaces that are serviced by the oil companies will rarely ever be downfired, even when stack temps are high, costing the customer money and wasting energy. These overfired units also short cycle leaving uneven temps thoughout the home. Pictures show signs of positive flue pressure instead of negative draft condition.

whoa!! that's funky town.
you can't stuff fiberglass up in the flue like that.
Was that a standard chimney with clay flue liner?
And was a new liner installed?
And is that liner rated for that type of install?
I don't think so!!
Now we have to assume that the whole kebab was installed by a non pro and will require at least a level II
Now how many other pics are you holding back?
Best for last Huh?
I'm still waiting to find the pot of gold up in there myself

A close look at the barometric damper reveals the stop for the gate has been modified so it holds it completely closed instead of being behind the ring to keep it from swinging outward.

Yes, either positive stack pressures, depressurized CAZ WRT stack, blocked flue or combination thereof. Sealing pipe joints with cement or tape is not a solution--setting up correctly is.

What we see of the venting is wholly unsuitable.

This unit will need a thorugh cleaning internally, proper set of lungs to vent it, then have a qualified pro techniican set it up then perform combustion analysis to ensure proper operation, which this ain't.

Originally Posted by wayne soper

Was that a standard chimney with clay flue liner?
And was a new liner installed?
And is that liner rated for that type of install?

I was not able to get to the top of this chimney for a look, it is way too high.
More than likely it is a new liner install but the markings are all concealed.

Originally Posted by Jon mackay

Bob,
That is starting to make more sense then.

See the pictures of the soot, the damper (note the left side restricting device), and the last is a picture looking up the flue from the cleanout.

Thank you for the info.

Jon, referring to your first picture. It appears that the stovepipe has been installed reversed. Had this issue in my home. This is based upon information furnished by the chimney manufacturer of my metal chimney and possibly others. They want to see the chimney and the stovepipe assembled in such a way that should condensation or rain enter the chimney, it will flow down into the firebox and not out of a coupling. If the stovepipe and chimney are assembled correctly this will not have any effect on combustion gases escaping through the connections.

Originally Posted by Rich Goeken

Jon, referring to your first picture. It appears that the stovepipe has been installed reversed. Had this issue in my home. This is based upon information furnished by the chimney manufacturer of my metal chimney and possibly others. They want to see the chimney and the stovepipe assembled in such a way that should condensation or rain enter the chimney, it will flow down into the firebox and not out of a coupling. If the stovepipe and chimney are assembled correctly this will not have any effect on combustion gases escaping through the connections.

Crimped ends of smoke pipe should always lead toward the chimney or flue connecter. The only time condensation should flow back to a unit would be direct vent gas units, as they are equipped for condensation removal. To do so with an oil fired furnace or boiler is asinine. Fireboxes and flame target materials do not stand up well to moisture and it would more than likely void any warranty.

Originally Posted by David Bell

Crimped ends of smoke pipe should always lead toward the chimney or flue connecter. The only time condensation should flow back to a unit would be direct vent gas units, as they are equipped for condensation removal. To do so with an oil fired furnace or boiler is asinine. Fireboxes and flame target materials do not stand up well to moisture and it would more than likely void any warranty.

Actually, this is exactly the opposite of was explained to me by the folks that make the chimney and stovepipe including a comment that the fireboxes (oil) are designed for such an occurrence. Don't know if the info was thrown out by now as it was awhile ago, will look around for it tomorrow.

Originally Posted by Rich Goeken

Actually, this is exactly the opposite of was explained to me by the folks that make the chimney and stovepipe including a comment that the fireboxes (oil) are designed for such an occurrence. Don't know if the info was thrown out by now as it was awhile ago, will look around for it tomorrow.

12. The slope of the horizontal portion of a connector of 1/4 inch
per foot is sometimes a building code requirement. This slope
will have little effect on safety, appliance operation or creosote
drips. If the connector is vertical, it should be installed with the
crimped end down. If it can be sloped between the stove and
chimney, use 45 degree one piece leakproof elbows (such as
the corrugated type), and try to maintain sufficient slope so that
any condensate liquid runs back toward the appliance. To keep
liquids from coming out connector joints, the small (or crimped)

end should always be down - or toward the stove or fireplace.

Underlining is mine. This may be what you remembered but does not apply to furnace applications.

Originally Posted by David Bell

12. The slope of the horizontal portion of a connector of 1/4 inch
per foot is sometimes a building code requirement. This slope
will have little effect on safety, appliance operation or creosote
drips. If the connector is vertical, it should be installed with the
crimped end down. If it can be sloped between the stove and
chimney, use 45 degree one piece leakproof elbows (such as
the corrugated type), and try to maintain sufficient slope so that
any condensate liquid runs back toward the appliance. To keep
liquids from coming out connector joints, the small (or crimped)

end should always be down - or toward the stove or fireplace.

Underlining is mine. This may be what you remembered but does not apply to furnace applications.

Dave,

Finally located the letter from the manufacturer of the L-vent chimney system, Airjet, that is installed in the house. He indicates in his letter "...the serrated end or male end goes toward the appliance, the top of the pipe that goes toward the top of the chimney is the female end."

Your quote above does not state anything about furnace applications. As I read it, it states that this applies to stove or fireplace only, no mention of any other devices.

As it does not indicate any installation requirements for a furnace, the piping therefore may be installed at the installers discretion. or in accordance with other codes and/or manufacturers installation instructions such as Airjet's.

"AirJet pipe and fi ttings are assembled with the exclusive
Snap-Lock system. Always follow UP arrows on label - male
end up. Engage male and female end inner liners and directly
line up locks. The “button punches” on the male end line up
with the folded-under tabs on the female end. As an easy
frame of reference, if you line up the exterior pipe seams
the locks will be in the proper position. Push straight down
to securely snap lock, all the way around the joint. (No
twisting is necessary.)
If sections need to be disengaged, fi rst pull up against the
joint (this re-engages the locks). Then twist the upper section
counter clockwise, and pull up to unlock."

Having installed a few miles of Air Jet venting, let me explain: What they refer to as the 'male' end is actually the upper end as referenced by the 'up' stamping on the pipe. This is the male end of the outer casing, which engages into the female lower end to provide a reasonably water tight joint. Flip the vent over and you'll get water entry just like shingling upside down.
Now, the inner sections are the opposite: the male end points downwards and engages into the preceding female end for a drip free joint. This is the same orientation for factory chimney and B-vent as well.

So, don't try to overthink this one--follow the arrows on the vent. BTW, the venting instructions reference oil burning appliances approved for L vent with a max stack temp. of 570*F and Cat I gas appliances, which are approved for B-vent.
HTH,