The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

"blueman" wrote in message
...
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

Well there you go. Those Xs are there for a reason. Get the installer back
to do the job right. Otherwise, you'll have to add some external
stiffening.

On Jan 21, 1:42*am, blueman wrote:
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

Go to lowes and get a small piece of angled iron or aluminum. Can be
1/2" x 1/2". Cut to fit diagonally, drill holes, and put some screws
into the sheet metal.

On Jan 21, 12:42*am, blueman wrote:
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

Maybe returns and vents are to small

"Ed P" writes:
"blueman" wrote in message
...
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

Well there you go. Those Xs are there for a reason. Get the installer back
to do the job right. Otherwise, you'll have to add some external
stiffening.

Wish I could but it was installed 10 years ago - under the previous
owner.
External stiffening is probably the simplest solution though I could use
some pointers on specifics...

(ultimately, I will need to redo all the ductwork to replace the flex
duct hack)

ransley writes:

On Jan 21, 12:42Â*am, blueman wrote:
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

Maybe returns and vents are to small
Probably not enough returns plus constriction in the awful mess of
flexduct.
But I can't replace it all now for many reasons so I need an interim fix
that works.

jamesgangnc writes:

On Jan 21, 1:42Â*am, blueman wrote:
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

Go to lowes and get a small piece of angled iron or aluminum. Can be
1/2" x 1/2". Cut to fit diagonally, drill holes, and put some screws
into the sheet metal.

Do I really need angle iron? Wouldn't that stick out and look awkward
(and potentially be dangerous by sticking out that way)

Would using thick enough iron banding work? I was thinking of making one
or two bands wrap around the 3 accessible sides.

I imagine all I need to do is overcome the net suction effect of the
blower (net of the air flowing through the returns and net of the static
bending resistance of the sheet metal plenum).

On Jan 21, 12:30*pm, blueman wrote:
jamesgangnc writes:
On Jan 21, 1:42*am, blueman wrote:
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

Go to lowes and get a small piece of angled iron or aluminum. *Can be
1/2" x 1/2". Cut to fit diagonally, drill holes, and put some screws
into the sheet metal.

Do I really need angle iron? Wouldn't that stick out and look awkward
(and potentially be dangerous by sticking out that way)

Would using thick enough iron banding work? I was thinking of making one
or two bands wrap around the 3 accessible sides.

I imagine all I need to do is overcome the net suction effect of the
blower (net of the air flowing through the returns and net of the static
bending resistance of the sheet metal plenum).- Hide quoted text -

- Show quoted text -

I think that the poster recommending use of angle iron meant to put it
parallel to the plenum over a considerable distance to stiffen it.
Or, if you know where the bowing occurs, the angle iron could be cut
to length and placed at rightr angles to the plenum to stiffen it at
that point. But if the plenum is in the ceiling rafters of the
basement, 1/2 inch sticking down shouldn't make any difference unless
you basketball team members using your basement.

On Jan 21, 12:42*am, blueman wrote:
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

Cutting a hole for a basement return might do it, I did it.

On 1/21/2010 13:02, ransley wrote:

Cutting a hole for a basement return might do it, I did it.

That may cause problems depending on the proximity to the furnace with
the return air duct drawing in combustion air. As for the angle iron
idea, this doesn't have to be iron; aluminum may be used. It only needs
to be strong enough to stop the sheet metal from flexing.

On Jan 21, 6:49*pm, Bob wrote:
On 1/21/2010 13:02, ransley wrote:

Cutting a hole for a basement return might do it, I did it.

That may cause problems depending on the proximity to the furnace with
the return air duct drawing in combustion air. *As for the angle iron
idea, this doesn't have to be iron; aluminum may be used. *It only needs
to be strong enough to stop the sheet metal from flexing.

Since when do furnaces need ducted returns, Ive seen no return ducts
many times, just the furnace intake.

On Jan 21, 8:50*pm, ransley wrote:
On Jan 21, 6:49*pm, Bob wrote:

On 1/21/2010 13:02, ransley wrote:

Cutting a hole for a basement return might do it, I did it.

That may cause problems depending on the proximity to the furnace with
the return air duct drawing in combustion air. *As for the angle iron
idea, this doesn't have to be iron; aluminum may be used. *It only needs
to be strong enough to stop the sheet metal from flexing.

Since when do furnaces need ducted returns, Ive seen no return ducts
many times, just the furnace intake.

In colder cliimates a return plenum is almost always necessary to
circulate ari in rooms far from the furnace. Houses you saw must have
been 40 - 50+ years old.

"hr(bob) " writes:

On Jan 21, 12:30Â*pm, blueman wrote:
jamesgangnc writes:
On Jan 21, 1:42Â*am, blueman wrote:
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

Go to lowes and get a small piece of angled iron or aluminum. Â*Can be
1/2" x 1/2". Cut to fit diagonally, drill holes, and put some screws
into the sheet metal.

Do I really need angle iron? Wouldn't that stick out and look awkward
(and potentially be dangerous by sticking out that way)

Would using thick enough iron banding work? I was thinking of making one
or two bands wrap around the 3 accessible sides.

I imagine all I need to do is overcome the net suction effect of the
blower (net of the air flowing through the returns and net of the static
bending resistance of the sheet metal plenum).- Hide quoted text -

- Show quoted text -

I think that the poster recommending use of angle iron meant to put it
parallel to the plenum over a considerable distance to stiffen it.
Or, if you know where the bowing occurs, the angle iron could be cut
to length and placed at rightr angles to the plenum to stiffen it at
that point. But if the plenum is in the ceiling rafters of the
basement, 1/2 inch sticking down shouldn't make any difference unless
you basketball team members using your basement.

The plenum is actually vertically oriented, sitting on the floor
adjacent to the furnace which is why I was concerned about having
something sticking out that people could bang into (given that the space
is a bit cramped there).

The bowing and banging (which I have been told is properly called
"oil-canning") occurs very prominently across the middle of the "belly"
of the plenum so I'm not sure that angle iron along the edges will help
enough since the problem doesn't seem to be along the edges per-se.

I bought some more "ess cleat" last night and it actually seems to be
about as stiff as 1/8" flat iron (note "drive cleat" was significantly
less stiff which is understandable since it has 2 (at most) layers vs
the 3 plus layers for ess cleat). I figure if I need more stiffness I
could even interdigitate two pieces of ess cleat to get an even more
ridgid band.

I will let you know how this works...

ransley writes:

On Jan 21, 12:42Â*am, blueman wrote:
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

Cutting a hole for a basement return might do it, I did it.

Actually, I think the banging problem became much worse because I
recently closed up an "inadvertent" basement return. Specifically, the
bottom end of the plenum was open but sitting on the rough basement
floor. I had previously used metal tape to try to seal it off but
recently did it right with a sheet metal cap. So, in a sense you are
right.

But my understanding is that it is not a good idea to do that for
several reasons:
1. It draws in the cooler (unheated) basement air which needs to be
heated and ultimately results in either heating the basement or
drawing in more cold air from outside since the air has to be
replaced from somewhere.

2. The negative pressure could draw in more radon (and we have that here
in granite-laden New England). This is a concern particularly since
our basement floor is 150 years old so it is not fully intact and we
also have a crawl space with only a loose fitting vapor barrier
covering the raw earth.

3. If there are any open combustion chambers in furnaces or water
heaters, the negative pressure may draw combustion gasses and CO
into the basement and from there through the return into the house.

3. More generally, you will draw in fumes and other potentially
undesirable odors, gasses, etc. from the basement.

On Jan 21, 10:17*pm, "hr(bob) "
wrote:
On Jan 21, 8:50*pm, ransley wrote:

On Jan 21, 6:49*pm, Bob wrote:

On 1/21/2010 13:02, ransley wrote:

Cutting a hole for a basement return might do it, I did it.

That may cause problems depending on the proximity to the furnace with
the return air duct drawing in combustion air. *As for the angle iron
idea, this doesn't have to be iron; aluminum may be used. *It only needs
to be strong enough to stop the sheet metal from flexing.

Since when do furnaces need ducted returns, Ive seen no return ducts
many times, just the furnace intake.

In colder cliimates a return plenum is almost always necessary to
circulate ari in rooms far from the furnace. *Houses you saw must have
been 40 - 50+ years old.

Im where houses are 200 yrs old, but AC is the only reason you actualy
need returns on every floor, sure its probably more even heat with
returns but I think his are undersized, even a small 2" vent in the
basement would help and circulate heat better, but if he has AC he
need a pro to evaluate his ductwork sizing, whith my new unit thats
exactly what the installer did and found my returns to small, we added
alot more and it help balance temps.

On Jan 22, 7:44*am, blueman wrote:
ransley writes:
On Jan 21, 12:42*am, blueman wrote:
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

Cutting a hole for a basement return might do it, I did it.

Actually, I think the banging problem became much worse because I
recently closed up an "inadvertent" basement return. Specifically, the
bottom end of the plenum was open but sitting on the rough basement
floor. I had previously used metal tape to try to seal it off but
recently did it right with a sheet metal cap. So, in a sense you are
right.

But my understanding is that it is not a good idea to do that for
several reasons:
1. It draws in the cooler (unheated) basement air which needs to be
* *heated and ultimately results in either heating the basement or
* *drawing in more cold air from outside since the air has to be
* *replaced from somewhere.

2. The negative pressure could draw in more radon (and we have that here
* *in granite-laden New England). This is a concern particularly since
* *our basement floor is 150 years old so it is not fully intact and we
* *also have a crawl space with only a loose fitting vapor barrier
* *covering the raw earth.

3. If there are any open combustion chambers in furnaces or water
* *heaters, the negative pressure may draw combustion gasses and CO
* *into the basement and from there through the return into the house..

3. More generally, you will draw in fumes and other potentially
* *undesirable odors, gasses, etc. from the basement.- Hide quoted text -

- Show quoted text -

1. 2. 3. 3. sure if you want a cold unused basement,

On Jan 22, 8:36*am, blueman wrote:
I bought some more "ess cleat" last night and it actually seems to be
about as stiff as 1/8" flat iron (note "drive cleat" was significantly
less stiff which is understandable since it has 2 (at most) layers vs
the 3 plus layers for ess cleat). I figure if I need more stiffness I
could even interdigitate two pieces of ess cleat to get an even more
ridgid band.

I will let you know how this works

If it's about as stiff as 1/8" flat steel, you're wasting your time.
Even 1/16"x1/2" angle aluminum will provide way more stiffening than
1/8" flat steel.

1/2" ain't gonna kill ya. Just round off the corners with an angle
grinder or belt sander and screw it on, either in an X pattern across
the panel that's bowing, or horizontally across the middle of the
panel, making sure to overlap the ends.

On Jan 22, 9:31*am, ransley wrote:
*1. 2. 3. 3. sure if you want a cold unused basement

Doesn't sound like you'd want to use his basement even if it was warm.

On Jan 22, 10:19*am, wrote:
On Jan 22, 8:36*am, blueman wrote:

I bought some more "ess cleat" last night and it actually seems to be
about as stiff as 1/8" flat iron (note "drive cleat" was significantly
less stiff which is understandable since it has 2 (at most) layers vs
the 3 plus layers for ess cleat). I figure if I need more stiffness I
could even interdigitate two pieces of ess cleat to get an even more
ridgid band.

I will let you know how this works

If it's about as stiff as 1/8" flat steel, you're wasting your time.
Even 1/16"x1/2" angle aluminum will provide way more stiffening than
1/8" flat steel.

1/2" ain't gonna kill ya. Just round off the corners with an angle
grinder or belt sander and screw it on, either in an X pattern across
the panel that's bowing, or horizontally across the middle of the
panel, making sure to overlap the ends.

One piece of angle stock placed diagonally across the middle where it
is oil canning will fix it.

blueman wrote:
The sheet metal return plenum on one of our 2 otherwise identical gas
furnaces gives out a loud "bang" as the duct contracts inwards when the
blower starts and again when the duct returns to its original
conformation when the blower stops.

The other furnace that doesn't "bang" seems to have a relief "X" on its
broad surface while the one that does "bang" doesn't have the "X".

The return plenum is 24"x8"x60".

I would prefer not to reduce the blower speed since the furnace is in
the basement and needs to provide forced air all the way to the 2nd and
3rd floors and the ductwork is highly non-optimal (the previous owner
had some hack do it with a maze of flex duct -- one day I will have it
replaced but not now...)

I have heard about people using "banding" to stiffen up the plenum and
reduce the movement but am not sure of the best way.

So...
1. What is the recommended way to eliminate such movement and "banging"?

2. If some type of banding is appropriate, what are the appropriate
materials and techniques to do it in a professional and neat manner?

THANKS!!!!

You don't necessarily need to stiffen the duct. If you can get inside
you can wedge a piece of wood between middle of the sides that 'oil can'
(pushing them apart).

You can put blocks of wood on the center of the sides that 'oil can' and
tie a rope around the duct to push the blocks in. (With a little thought
you could the same thing much better.)

--
bud--

On Fri, 22 Jan 2010 07:19:59 -0800 (PST),
wrote:

On Jan 22, 8:36Â*am, blueman wrote:
I bought some more "ess cleat" last night and it actually seems to be
about as stiff as 1/8" flat iron (note "drive cleat" was significantly
less stiff which is understandable since it has 2 (at most) layers vs
the 3 plus layers for ess cleat). I figure if I need more stiffness I
could even interdigitate two pieces of ess cleat to get an even more
ridgid band.

I will let you know how this works

If it's about as stiff as 1/8" flat steel, you're wasting your time.
Even 1/16"x1/2" angle aluminum will provide way more stiffening than
1/8" flat steel.

1/2" ain't gonna kill ya. Just round off the corners with an angle
grinder or belt sander and screw it on, either in an X pattern across
the panel that's bowing, or horizontally across the middle of the
panel, making sure to overlap the ends.
For oil canning, go across corner and it will be about twice as
evvective as either horizontal or vertical.

writes:
On Jan 22, 8:36Â*am, blueman wrote:
I bought some more "ess cleat" last night and it actually seems to be
about as stiff as 1/8" flat iron (note "drive cleat" was significantly
less stiff which is understandable since it has 2 (at most) layers vs
the 3 plus layers for ess cleat). I figure if I need more stiffness I
could even interdigitate two pieces of ess cleat to get an even more
ridgid band.

I will let you know how this works

If it's about as stiff as 1/8" flat steel, you're wasting your time.
Even 1/16"x1/2" angle aluminum will provide way more stiffening than
1/8" flat steel.

1/2" ain't gonna kill ya. Just round off the corners with an angle
grinder or belt sander and screw it on, either in an X pattern across
the panel that's bowing, or horizontally across the middle of the
panel, making sure to overlap the ends.

I ended up using aluminum angle iron but mounted it on the inside so I
got all the stiffness I needed without any protrusions -- all I had to
do was to remove one of the ducts which gave me access to the interior
of the plenum. I then used sheet metal screws to secure two horizontal
pieces of angle iron.

ransley writes:
On Jan 21, 10:17Â*pm, "hr(bob) "
wrote:
On Jan 21, 8:50Â*pm, ransley wrote:

On Jan 21, 6:49Â*pm, Bob wrote:

On 1/21/2010 13:02, ransley wrote:

Cutting a hole for a basement return might do it, I did it.

That may cause problems depending on the proximity to the furnace with
the return air duct drawing in combustion air. Â*As for the angle iron
idea, this doesn't have to be iron; aluminum may be used. Â*It only needs
to be strong enough to stop the sheet metal from flexing.

Since when do furnaces need ducted returns, Ive seen no return ducts
many times, just the furnace intake.

In colder cliimates a return plenum is almost always necessary to
circulate ari in rooms far from the furnace. Â*Houses you saw must have
been 40 - 50+ years old.

Im where houses are 200 yrs old, but AC is the only reason you actualy
need returns on every floor, sure its probably more even heat with
returns but I think his are undersized, even a small 2" vent in the
basement would help and circulate heat better, but if he has AC he
need a pro to evaluate his ductwork sizing, whith my new unit thats
exactly what the installer did and found my returns to small, we added
alot more and it help balance temps.

Parts of our house are over 200 years old in fact... and the central
heating was probably put in about 100 years ago.

We do plan to put in AC which as you note requires returns on the higher
floors to work properly -- in fact, one of our reasons for not investing
in the HVAC work now is that we want to do it all right when we add AC
and do renovations rather than doing it half-assed multiple times...

That way, you're not ripping clothes when you walk by. Good
idea.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"blueman" wrote in message
...

I ended up using aluminum angle iron but mounted it on the
inside so I
got all the stiffness I needed without any protrusions --
all I had to
do was to remove one of the ducts which gave me access to
the interior
of the plenum. I then used sheet metal screws to secure two
horizontal
pieces of angle iron.

I've seen it done with a section of allthread, with washers
and nuts to establish a 'pinched' distance, and the nuts on
the outer portion to snug it in.

On Jan 24, 3:58*pm, blueman wrote:
writes:
On Jan 22, 8:36*am, blueman wrote:
I bought some more "ess cleat" last night and it actually seems to be
about as stiff as 1/8" flat iron (note "drive cleat" was significantly
less stiff which is understandable since it has 2 (at most) layers vs
the 3 plus layers for ess cleat). I figure if I need more stiffness I
could even interdigitate two pieces of ess cleat to get an even more
ridgid band.

I will let you know how this works

If it's about as stiff as 1/8" flat steel, you're wasting your time.
Even 1/16"x1/2" angle aluminum will provide way more stiffening than
1/8" flat steel.

1/2" ain't gonna kill ya. Just round off the corners with an angle
grinder or belt sander and screw it on, either in an X pattern across
the panel that's bowing, or horizontally across the middle of the
panel, making sure to overlap the ends.

I ended up using aluminum angle iron but mounted it on the inside so I
got all the stiffness I needed without any protrusions -- all I had to
do was to remove one of the ducts which gave me access to the interior
of the plenum. I then used sheet metal screws to secure two horizontal
pieces of angle iron.

blueman wrote:
writes:
On Jan 22, 8:36 am, blueman wrote:
I bought some more "ess cleat" last night and it actually seems to be
about as stiff as 1/8" flat iron (note "drive cleat" was significantly
less stiff which is understandable since it has 2 (at most) layers vs
the 3 plus layers for ess cleat). I figure if I need more stiffness I
could even interdigitate two pieces of ess cleat to get an even more
ridgid band.

I will let you know how this works
If it's about as stiff as 1/8" flat steel, you're wasting your time.
Even 1/16"x1/2" angle aluminum will provide way more stiffening than
1/8" flat steel.

1/2" ain't gonna kill ya. Just round off the corners with an angle
grinder or belt sander and screw it on, either in an X pattern across
the panel that's bowing, or horizontally across the middle of the
panel, making sure to overlap the ends.

I ended up using aluminum angle iron but mounted it on the inside so I
got all the stiffness I needed without any protrusions -- all I had to
do was to remove one of the ducts which gave me access to the interior
of the plenum. I then used sheet metal screws to secure two horizontal
pieces of angle iron.

Aluminum angle iron? Could you tell me where I might find such an
interesting metal alloy? *snicker*

TDD

The Daring Dufas writes:

blueman wrote:
writes:
On Jan 22, 8:36 am, blueman wrote:
I bought some more "ess cleat" last night and it actually seems to be
about as stiff as 1/8" flat iron (note "drive cleat" was significantly
less stiff which is understandable since it has 2 (at most) layers vs
the 3 plus layers for ess cleat). I figure if I need more stiffness I
could even interdigitate two pieces of ess cleat to get an even more
ridgid band.

I will let you know how this works
If it's about as stiff as 1/8" flat steel, you're wasting your time.
Even 1/16"x1/2" angle aluminum will provide way more stiffening than
1/8" flat steel.

1/2" ain't gonna kill ya. Just round off the corners with an angle
grinder or belt sander and screw it on, either in an X pattern across
the panel that's bowing, or horizontally across the middle of the
panel, making sure to overlap the ends.

I ended up using aluminum angle iron but mounted it on the inside so I
got all the stiffness I needed without any protrusions -- all I had to
do was to remove one of the ducts which gave me access to the interior
of the plenum. I then used sheet metal screws to secure two horizontal
pieces of angle iron.

Aluminum angle iron? Could you tell me where I might find such an
interesting metal alloy? *snicker*

It's in the same aisle as the hot water heater...