If I put a box over the heat vent in the kitchen
and over the living room, might not heat those
rooms as much. Save a buck on energy?

Anyone tried this?

Gonna be below zero tonight, and windy. My heat
bill will be up a bit, or a lot.

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

On 02/27/2014 03:44 PM, Stormin Mormon wrote:
If I put a box over the heat vent in the kitchen
and over the living room, might not heat those
rooms as much. Save a buck on energy?

Anyone tried this?

Gonna be below zero tonight, and windy. My heat
bill will be up a bit, or a lot.




Yeah


A few years back I closed the vents totally to two rooms and just kept
the doors closed and saved money.

On 2/27/2014 5:26 PM, philo wrote:


Yeah

A few years back I closed the vents totally to two rooms and just kept
the doors closed and saved money.

Thank you. I don't have any way to compare
open or closed vents, but I'll try it.


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

Stormin Mormon wrote:
If I put a box over the heat vent in the kitchen
and over the living room, might not heat those
rooms as much. Save a buck on energy?

Anyone tried this?

Gonna be below zero tonight, and windy. My heat
bill will be up a bit, or a lot.


Can you close the ductwork closer to the furnace? That would probably be
better than just a box over the vent.

Is there a cold air return in those rooms? I closed the vents to an unused
bedroom then realized I was sucking 60° air back down to the furnace
through the cold air return. That's not very efficient. I made a cover
from a rubber pad and put a heavy box in front of the return to stop it
from sucking air.

On Thu, 27 Feb 2014 23:16:10 +0000 (UTC), DerbyDad03
wrote:

Stormin Mormon wrote:
If I put a box over the heat vent in the kitchen
and over the living room, might not heat those
rooms as much. Save a buck on energy?

Anyone tried this?

Yes, years ago and I'm still doing it. Well, I close the vent using the
lever that does that. I assume I'm saving money to the extent parts of
the house (that I don't use much) are colder than they would be. The
basement is definitely colder. In fact maybe I should open the vent
since now I have the computer down here and I'm here so much. I have
the spare bedroom door closed, a towell under its door, and the vent
closed, and it's definitely cooler in that room. Never gets cold I
think. Maybe heat goes through the door and the walls. Etc .

I've been told, here probably, that if I close too many, that will cause
combustion problems with my oil furnace, but now that I think about it,
that makes little or no sense. The air I'm preventing from circulating
is not the combustion air. That comes in somewhere (????) and goes out
the chimney.

The air I'm stopping is the air on the other side of the heat exchanger.
If that circulates less, I suppose it gets hotter while it's in the
furnace, but not so hot it's going to heat the fire chamber** and change
the combustion characteristics of the oil fire.

**That is, fail to cool the fire chamber as much. It will do that a
little, but it's already so hot in the middle of an atomized oil fire, I
don't think it will change anything.

Gonna be below zero tonight, and windy. My heat
bill will be up a bit, or a lot.


Can you close the ductwork closer to the furnace? That would probably be
better than just a box over the vent.

I can't.

Is there a cold air return in those rooms? I closed the vents to an unused

No. The first two houses I lived in were built right and had that, but
I only have two air returns, one close to the celing of the second floor
in the stairwell, and one close to the floor of the basement in the same
stairwell. The second is only about an 18 inche duct ride to the
furnace input.

No doors to close off the stairs, or separate the living room from the
dining "area" or the hall from the kitchen. But it makes a small house
look and feel bigger when heat and AC are not a consideration.


bedroom then realized I was sucking 60° air back down to the furnace
through the cold air return. That's not very efficient.

Not good, for sure, but not so much the part where you reheat 60* air.
That just makes it easier to heat. I think the problem that was bad, or
worse, was heating the room you intended to be cool

I made a cover
from a rubber pad and put a heavy box in front of the return to stop it
from sucking air.

V. Good.

micky wrote:
On Thu, 27 Feb 2014 23:16:10 +0000 (UTC), DerbyDad03
wrote:

Stormin Mormon wrote:
If I put a box over the heat vent in the kitchen
and over the living room, might not heat those
rooms as much. Save a buck on energy?

Anyone tried this?

Yes, years ago and I'm still doing it. Well, I close the vent using the
lever that does that. I assume I'm saving money to the extent parts of
the house (that I don't use much) are colder than they would be. The
basement is definitely colder. In fact maybe I should open the vent
since now I have the computer down here and I'm here so much. I have
the spare bedroom door closed, a towell under its door, and the vent
closed, and it's definitely cooler in that room. Never gets cold I
think. Maybe heat goes through the door and the walls. Etc .

I've been told, here probably, that if I close too many, that will cause
combustion problems with my oil furnace, but now that I think about it,
that makes little or no sense. The air I'm preventing from circulating
is not the combustion air. That comes in somewhere (????) and goes out
the chimney.

The air I'm stopping is the air on the other side of the heat exchanger.
If that circulates less, I suppose it gets hotter while it's in the
furnace, but not so hot it's going to heat the fire chamber** and change
the combustion characteristics of the oil fire.

**That is, fail to cool the fire chamber as much. It will do that a
little, but it's already so hot in the middle of an atomized oil fire, I
don't think it will change anything.

Gonna be below zero tonight, and windy. My heat
bill will be up a bit, or a lot.


Can you close the ductwork closer to the furnace? That would probably be
better than just a box over the vent.

I can't.

Is there a cold air return in those rooms? I closed the vents to an unused

No. The first two houses I lived in were built right and had that, but
I only have two air returns, one close to the celing of the second floor
in the stairwell, and one close to the floor of the basement in the same
stairwell. The second is only about an 18 inche duct ride to the
furnace input.

No doors to close off the stairs, or separate the living room from the
dining "area" or the hall from the kitchen. But it makes a small house
look and feel bigger when heat and AC are not a consideration.


bedroom then realized I was sucking 60° air back down to the furnace
through the cold air return. That's not very efficient.

Not good, for sure, but not so much the part where you reheat 60* air.
That just makes it easier to heat. I think the problem that was bad, or
worse, was heating the room you intended to be cool

I'm not sure what you are trying to say here. In reverse order, why do you
think something was heating the room I was intending to be cool? The heat
ducts were closed at the furnace. No heat was blowing into the room. It was
definitely cool in that room, sometimes into the mid-50s during the
coldest days.

As far as the return air, why would I want to mix 55° - 60° air in with the
68° degree from the rest of the house and then reheat it? Why isn't that a
bad thing?


I made a cover
from a rubber pad and put a heavy box in front of the return to stop it
from sucking air.

V. Good.

On Fri, 28 Feb 2014 04:03:04 +0000 (UTC), DerbyDad03
wrote:


Is there a cold air return in those rooms? I closed the vents to an unused

No. The first two houses I lived in were built right and had that, but
I only have two air returns, one close to the celing of the second floor
in the stairwell, and one close to the floor of the basement in the same
stairwell. The second is only about an 18 inche duct ride to the
furnace input.

No doors to close off the stairs, or separate the living room from the
dining "area" or the hall from the kitchen. But it makes a small house
look and feel bigger when heat and AC are not a consideration.


bedroom then realized I was sucking 60° air back down to the furnace
through the cold air return. That's not very efficient.

Not good, for sure, but not so much the part where you reheat 60* air.
That just makes it easier to heat. I think the problem that was bad, or
worse, was heating the room you intended to be cool

I'm not sure what you are trying to say here. In reverse order, why do you
think something was heating the room I was intending to be cool?

Because you were sucking heated air through the room on its way to the
retrun duct. It says 60° , which I presume is my computers version
of 60 degree. I dind't pay attention to that, but how could it be that
cold if it came from the heated part of your house. I get it. The
room was 60, but when you sucked out the 60 degree air it was replaced
with 67 degree air from the rest of the house, so that's warming the
room, and cooling part of the return air. .

The heat
ducts were closed at the furnace. No heat was blowing into the room. It was
definitely cool in that room, sometimes into the mid-50s during the
coldest days.

As far as the return air, why would I want to mix 55° - 60° air in with the
68° degree from the rest of the house

I don't know if you want to but isn't that what happens when the cold
air duct was sucking air out of the room. That air was replaced with
air from the rest of the house, right?

Or from leaks around the windows I guess. if that was most of it, then
I'm mostly wrong.

So from which entryway, both of which were intended to be close, is
leaking air into the room more.

and then reheat it? Why isn't that a
bad thing?

When I posted, I thought -- and it still may be the case afaik -- that
the air was 60 because it cooled off in the unheated room (while heating
the room) and it had been 67 say, because it came from the heated
rooms. I figure you have to reheat the air no matter where it came from,
but the problem was that it was 60, and that happened in the unheated
room.

So now I don't know where the return air from that room comes from, the
rest of hte house or the outside.

Sorry for the confusion.

In article ,
Stormin Mormon wrote:

If I put a box over the heat vent in the kitchen
and over the living room, might not heat those
rooms as much. Save a buck on energy?

if you put a box, and it would be quite a big box, over the living room
you wouldn't be able to get in or out



Anyone tried this?

Gonna be below zero tonight, and windy. My heat
bill will be up a bit, or a lot.

"Stormin Mormon" wrote in message
...
If I put a box over the heat vent in the kitchen
and over the living room, might not heat those
rooms as much. Save a buck on energy?

Anyone tried this?

Gonna be below zero tonight, and windy. My heat
bill will be up a bit, or a lot.

Hah. You Yanks really are in the dark ages,like a hundred years behind the
rest of civilisation.
My house needs no heating most of the Winter I have two feet of insulation
in the walls.
The TV and freezers keep the place warm

"micky" wrote in message
...
On Fri, 28 Feb 2014 04:03:04 +0000 (UTC), DerbyDad03
wrote:


Is there a cold air return in those rooms? I closed the vents to an
unused

No. The first two houses I lived in were built right and had that, but
I only have two air returns, one close to the celing of the second floor
in the stairwell, and one close to the floor of the basement in the same
stairwell. The second is only about an 18 inche duct ride to the
furnace input.

No doors to close off the stairs, or separate the living room from the
dining "area" or the hall from the kitchen. But it makes a small house
look and feel bigger when heat and AC are not a consideration.


bedroom then realized I was sucking 60° air back down to the furnace
through the cold air return. That's not very efficient.

Not good, for sure, but not so much the part where you reheat 60* air.
That just makes it easier to heat. I think the problem that was bad, or
worse, was heating the room you intended to be cool

I'm not sure what you are trying to say here. In reverse order, why do you
think something was heating the room I was intending to be cool?

Because you were sucking heated air through the room on its way to the
retrun duct. It says 60° , which I presume is my computers version
of 60 degree. I dind't pay attention to that, but how could it be that
cold if it came from the heated part of your house. I get it. The
room was 60, but when you sucked out the 60 degree air it was replaced
with 67 degree air from the rest of the house, so that's warming the
room, and cooling part of the return air. .

The heat
ducts were closed at the furnace. No heat was blowing into the room. It
was
definitely cool in that room, sometimes into the mid-50?Ts during the
coldest days.

As far as the return air, why would I want to mix 55° - 60° air in with
the
68° degree from the rest of the house

I don't know if you want to but isn't that what happens when the cold
air duct was sucking air out of the room. That air was replaced with
air from the rest of the house, right?

Or from leaks around the windows I guess. if that was most of it, then
I'm mostly wrong.

So from which entryway, both of which were intended to be close, is
leaking air into the room more.

and then reheat it? Why isn't that a
bad thing?

When I posted, I thought -- and it still may be the case afaik -- that
the air was 60 because it cooled off in the unheated room (while heating
the room) and it had been 67 say, because it came from the heated
rooms. I figure you have to reheat the air no matter where it came from,
but the problem was that it was 60, and that happened in the unheated
room.

So now I don't know where the return air from that room comes from, the
rest of hte house or the outside.

Sorry for the confusion.

If you had a non-primitive heating system, the combustion air would be drawn
from outside the building directly into the furnace/boiler, not drawn
through the house. (Balanced flue/room sealed)

If you close off your combustion air vents, you risk carbon monoxide
poisoning.

http://www.centralheating.org.uk/Cen...iler_Flues.htm

You need to catch up with the rest of the world.

On 2/27/2014 11:24 PM, micky wrote:
When I posted, I thought -- and it still may be the case afaik -- that
the air was 60 because it cooled off in the unheated room (while heating
the room) and it had been 67 say, because it came from the heated
rooms. I figure you have to reheat the air no matter where it came from,
but the problem was that it was 60, and that happened in the unheated
room.

So now I don't know where the return air from that room comes from, the
rest of hte house or the outside.

Sorry for the confusion.

In my case, the return air vent is in the
hall. If I close a vent in one of the two
small bedrooms, there will be no air flow.

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

On 2/27/2014 10:31 PM, micky wrote:
Yes, years ago and I'm still doing it. Well, I close the vent using the
lever that does that. I assume I'm saving money to the extent parts of
the house (that I don't use much) are colder than they would be. The
basement is definitely colder. In fact maybe I should open the vent
since now I have the computer down here and I'm here so much. I have
the spare bedroom door closed, a towell under its door, and the vent
closed, and it's definitely cooler in that room. Never gets cold I
think. Maybe heat goes through the door and the walls. Etc .

I've been told, here probably, that if I close too many, that will cause
combustion problems with my oil furnace, but now that I think about it,
that makes little or no sense. The air I'm preventing from circulating
is not the combustion air. That comes in somewhere (????) and goes out
the chimney.

The air I'm stopping is the air on the other side of the heat exchanger.
If that circulates less, I suppose it gets hotter while it's in the
furnace, but not so hot it's going to heat the fire chamber** and change
the combustion characteristics of the oil fire.

**That is, fail to cool the fire chamber as much. It will do that a
little, but it's already so hot in the middle of an atomized oil fire, I
don't think it will change anything.


The evidence of it working, is that rooms are
colder, and heat bill goes down. Hard to compare
heat bill, but got to figure it's doing some
thing.

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

On Friday, February 28, 2014 6:36:08 AM UTC-5, harry wrote:
"micky" wrote in message

...

On Fri, 28 Feb 2014 04:03:04 +0000 (UTC), DerbyDad03

wrote:





Is there a cold air return in those rooms? I closed the vents to an

unused



No. The first two houses I lived in were built right and had that, but

I only have two air returns, one close to the celing of the second floor

in the stairwell, and one close to the floor of the basement in the same

stairwell. The second is only about an 18 inche duct ride to the

furnace input.



No doors to close off the stairs, or separate the living room from the

dining "area" or the hall from the kitchen. But it makes a small house

look and feel bigger when heat and AC are not a consideration.





bedroom then realized I was sucking 60° air back down to the furnace

through the cold air return. That's not very efficient.



Not good, for sure, but not so much the part where you reheat 60* air..

That just makes it easier to heat. I think the problem that was bad, or

worse, was heating the room you intended to be cool



I'm not sure what you are trying to say here. In reverse order, why do you

think something was heating the room I was intending to be cool?



Because you were sucking heated air through the room on its way to the

retrun duct. It says 60° , which I presume is my computers version

of 60 degree. I dind't pay attention to that, but how could it be that

cold if it came from the heated part of your house. I get it. The

room was 60, but when you sucked out the 60 degree air it was replaced

with 67 degree air from the rest of the house, so that's warming the

room, and cooling part of the return air. .



The heat

ducts were closed at the furnace. No heat was blowing into the room. It

was

definitely cool in that room, sometimes into the mid-50?Ts during the

coldest days.



As far as the return air, why would I want to mix 55° - 60° air in with

the

68° degree from the rest of the house



I don't know if you want to but isn't that what happens when the cold

air duct was sucking air out of the room. That air was replaced with

air from the rest of the house, right?



Or from leaks around the windows I guess. if that was most of it, then

I'm mostly wrong.



So from which entryway, both of which were intended to be close, is

leaking air into the room more.



and then reheat it? Why isn't that a

bad thing?



When I posted, I thought -- and it still may be the case afaik -- that

the air was 60 because it cooled off in the unheated room (while heating

the room) and it had been 67 say, because it came from the heated

rooms. I figure you have to reheat the air no matter where it came from,

but the problem was that it was 60, and that happened in the unheated

room.



So now I don't know where the return air from that room comes from, the

rest of hte house or the outside.



Sorry for the confusion.



If you had a non-primitive heating system, the combustion air would be drawn

from outside the building directly into the furnace/boiler, not drawn

through the house. (Balanced flue/room sealed)



If you close off your combustion air vents, you risk carbon monoxide

poisoning.



http://www.centralheating.org.uk/Cen...iler_Flues.htm



You need to catch up with the rest of the world.

He's talking about the return air vents for a forced air
furnace, which has nothing to do with combustion air, idiot.

On Friday, February 28, 2014 6:24:28 AM UTC-5, harry wrote:
"Stormin Mormon" wrote in message

...

If I put a box over the heat vent in the kitchen

and over the living room, might not heat those

rooms as much. Save a buck on energy?



Anyone tried this?



Gonna be below zero tonight, and windy. My heat

bill will be up a bit, or a lot.



Hah. You Yanks really are in the dark ages,like a hundred years behind the

rest of civilisation.

My house needs no heating most of the Winter I have two feet of insulation

in the walls.

The TV and freezers keep the place warm

Just all the hot air that comes out of your mouth would keep
you warm anywhere.

On 2/28/2014 8:20 AM, wrote:
On Friday, February 28, 2014 6:24:28 AM UTC-5, harry wrote:

Hah. You Yanks really are in the dark ages,like a hundred years behind the
rest of civilisation.


Just all the hot air that comes out of your mouth would keep
you warm anywhere.

Sigh. Less than 24 hours, and look where the
conversation has gone. Will you kids learn to
play nice?

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

On Fri, 28 Feb 2014 11:24:28 -0000, "harryagain"
wrote:

Hah. You Yanks really are in the dark ages,like a hundred years behind the
rest of civilisation.

But, after only a couple of hundred years we know how to spell
civilization.

Go figger

"harryagain" wrote:
"micky" wrote in message
...
On Fri, 28 Feb 2014 04:03:04 +0000 (UTC), DerbyDad03
wrote:


Is there a cold air return in those rooms? I closed the vents to an
unused

No. The first two houses I lived in were built right and had that, but
I only have two air returns, one close to the celing of the second floor
in the stairwell, and one close to the floor of the basement in the same
stairwell. The second is only about an 18 inche duct ride to the
furnace input.

No doors to close off the stairs, or separate the living room from the
dining "area" or the hall from the kitchen. But it makes a small house
look and feel bigger when heat and AC are not a consideration.


bedroom then realized I was sucking 60° air back down to the furnace
through the cold air return. That's not very efficient.

Not good, for sure, but not so much the part where you reheat 60* air.
That just makes it easier to heat. I think the problem that was bad, or
worse, was heating the room you intended to be cool

I'm not sure what you are trying to say here. In reverse order, why do you
think something was heating the room I was intending to be cool?

Because you were sucking heated air through the room on its way to the
retrun duct. It says 60° , which I presume is my computers version
of 60 degree. I dind't pay attention to that, but how could it be that
cold if it came from the heated part of your house. I get it. The
room was 60, but when you sucked out the 60 degree air it was replaced
with 67 degree air from the rest of the house, so that's warming the
room, and cooling part of the return air. .

The heat
ducts were closed at the furnace. No heat was blowing into the room. It
was
definitely cool in that room, sometimes into the mid-50â?Ts during the
coldest days.

As far as the return air, why would I want to mix 55° - 60° air in with
the
68° degree from the rest of the house

I don't know if you want to but isn't that what happens when the cold
air duct was sucking air out of the room. That air was replaced with
air from the rest of the house, right?

Or from leaks around the windows I guess. if that was most of it, then
I'm mostly wrong.

So from which entryway, both of which were intended to be close, is
leaking air into the room more.

and then reheat it? Why isn't that a
bad thing?

When I posted, I thought -- and it still may be the case afaik -- that
the air was 60 because it cooled off in the unheated room (while heating
the room) and it had been 67 say, because it came from the heated
rooms. I figure you have to reheat the air no matter where it came from,
but the problem was that it was 60, and that happened in the unheated
room.

So now I don't know where the return air from that room comes from, the
rest of hte house or the outside.

Sorry for the confusion.

If you had a non-primitive heating system, the combustion air would be drawn
from outside the building directly into the furnace/boiler, not drawn
through the house. (Balanced flue/room sealed)

If you close off your combustion air vents, you risk carbon monoxide
poisoning.

http://www.centralheating.org.uk/Cen...iler_Flues.htm

You need to catch up with the rest of the world.

Just so that there is no misunderstanding, my cold air returns are not my
"combustion air vents".

While I do draw combustion air from inside the house, it is drawn in right
at the furnace through a dedicated inlet pipe.

Closing a cold air return in an unheated room won't impact the combustion
air intake.

On 2/28/2014 3:59 PM, Oren wrote:
Hah. You Yanks really are in the dark ages,like a hundred years behind the
rest of civilisation.

But, after only a couple of hundred years we know how to spell
civilization.

Go figger


You using the F word again?

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

On Fri, 28 Feb 2014 07:36:32 -0500, Stormin Mormon
wrote:

On 2/27/2014 10:31 PM, micky wrote:
Yes, years ago and I'm still doing it. Well, I close the vent using the
lever that does that. I assume I'm saving money to the extent parts of
the house (that I don't use much) are colder than they would be. The
basement is definitely colder. In fact maybe I should open the vent
since now I have the computer down here and I'm here so much. I have
the spare bedroom door closed, a towell under its door, and the vent
closed, and it's definitely cooler in that room. Never gets cold I
think. Maybe heat goes through the door and the walls. Etc .

I've been told, here probably, that if I close too many, that will cause
combustion problems with my oil furnace, but now that I think about it,
that makes little or no sense. The air I'm preventing from circulating
is not the combustion air. That comes in somewhere (????) and goes out
the chimney.

The air I'm stopping is the air on the other side of the heat exchanger.
If that circulates less, I suppose it gets hotter while it's in the
furnace, but not so hot it's going to heat the fire chamber** and change
the combustion characteristics of the oil fire.

**That is, fail to cool the fire chamber as much. It will do that a
little, but it's already so hot in the middle of an atomized oil fire, I
don't think it will change anything.

Another misunderstanding.

The evidence of it working,

I said at the top that I assume I'm saving money.

is that rooms are colder,

For just this reason.

and heat bill goes down. Hard to compare
heat bill, but got to figure it's doing some
thing.

I too can't really tell if the cost has gone down because I didnt' keep
records before I closed the vents, and I'd have to keep track of degree
days from one year to the next and gallons of oil delivered and it's too
much effort.

When I say at the end I don't think it will change anything, I mean I
don't think it will change the character of an oil (or gas) fire to
either make the air in the house dirtier or make more carbon monoxide,
or something else I wouldn't like. DD3 says the same thing, iiuc.
But someone here in the last 15 years once said it would, and iirc no
one posted a disagreement.

micky wrote:

....snip...

When I say at the end I don't think it will change anything, I mean I
don't think it will change the character of an oil (or gas) fire to
either make the air in the house dirtier or make more carbon monoxide,
or something else I wouldn't like. DD3 says the same thing, iiuc.

Just for the record, I don't recall making any comments related to dirty
air or carbon monoxide.

But someone here in the last 15 years once said it would, and iirc no
one posted a disagreement.

On Fri, 28 Feb 2014 16:16:09 -0500, Stormin Mormon
wrote:

On 2/28/2014 3:59 PM, Oren wrote:
Hah. You Yanks really are in the dark ages,like a hundred years behind the
rest of civilisation.

But, after only a couple of hundred years we know how to spell
civilization.

Go figger


You using the F word again?

Fugetaboutit. I don't have explain it to you.

On Fri, 28 Feb 2014 21:13:19 +0000 (UTC), DerbyDad03
wrote:

"harryagain" wrote:
"micky" wrote in message
...
On Fri, 28 Feb 2014 04:03:04 +0000 (UTC), DerbyDad03
wrote:


Is there a cold air return in those rooms? I closed the vents to an
unused

No. The first two houses I lived in were built right and had that, but
I only have two air returns, one close to the celing of the second floor
in the stairwell, and one close to the floor of the basement in the same
stairwell. The second is only about an 18 inche duct ride to the
furnace input.

No doors to close off the stairs, or separate the living room from the
dining "area" or the hall from the kitchen. But it makes a small house
look and feel bigger when heat and AC are not a consideration.


bedroom then realized I was sucking 60° air back down to the furnace
through the cold air return. That's not very efficient.

Not good, for sure, but not so much the part where you reheat 60* air.
That just makes it easier to heat. I think the problem that was bad, or
worse, was heating the room you intended to be cool

I'm not sure what you are trying to say here. In reverse order, why do you
think something was heating the room I was intending to be cool?

Because you were sucking heated air through the room on its way to the
retrun duct. It says 60° , which I presume is my computers version
of 60 degree. I dind't pay attention to that, but how could it be that
cold if it came from the heated part of your house. I get it. The
room was 60, but when you sucked out the 60 degree air it was replaced
with 67 degree air from the rest of the house, so that's warming the
room, and cooling part of the return air. .

The heat
ducts were closed at the furnace. No heat was blowing into the room. It
was
definitely cool in that room, sometimes into the mid-50?Ts during the
coldest days.

As far as the return air, why would I want to mix 55° - 60° air in with
the
68° degree from the rest of the house

I don't know if you want to but isn't that what happens when the cold
air duct was sucking air out of the room. That air was replaced with
air from the rest of the house, right?

Or from leaks around the windows I guess. if that was most of it, then
I'm mostly wrong.

So from which entryway, both of which were intended to be close, is
leaking air into the room more.

and then reheat it? Why isn't that a
bad thing?

When I posted, I thought -- and it still may be the case afaik -- that
the air was 60 because it cooled off in the unheated room (while heating
the room) and it had been 67 say, because it came from the heated
rooms. I figure you have to reheat the air no matter where it came from,
but the problem was that it was 60, and that happened in the unheated
room.

So now I don't know where the return air from that room comes from, the
rest of hte house or the outside.

Sorry for the confusion.

If you had a non-primitive heating system, the combustion air would be drawn
from outside the building directly into the furnace/boiler, not drawn
through the house. (Balanced flue/room sealed)

If you close off your combustion air vents, you risk carbon monoxide
poisoning.

http://www.centralheating.org.uk/Cen...iler_Flues.htm

You need to catch up with the rest of the world.

Just so that there is no misunderstanding, my cold air returns are not my
"combustion air vents".

While I do draw combustion air from inside the house, it is drawn in right
at the furnace through a dedicated inlet pipe.

Closing a cold air return in an unheated room won't impact the combustion
air intake.
No, but it MAY cause the furnace to "short cycle" because the plenum
temperature will rize too high due to restricted air flow. This causes
the high limit switch to shut off the burner untill the blower sucks
the heat out of the heat exchanger, when it will relight. This makes
the efficiency of the furnace drop SIGNIFICANTLY.

On 2/28/2014 7:21 PM, Oren wrote:
On Fri, 28 Feb 2014 16:16:09 -0500, Stormin Mormon
wrote:

On 2/28/2014 3:59 PM, Oren wrote:
Hah. You Yanks really are in the dark ages,like a hundred years behind the
rest of civilisation.

But, after only a couple of hundred years we know how to spell
civilization.

Go figger


You using the F word again?

Fugetaboutit. I don't have explain it to you.


I'm going to repost some thing you
wrote last month.....

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

On 2/28/2014 9:16 PM, wrote:

Closing a cold air return in an unheated room won't impact the combustion
air intake.

No, but it MAY cause the furnace to "short cycle" because the plenum
temperature will rize too high due to restricted air flow. This causes
the high limit switch to shut off the burner untill the blower sucks
the heat out of the heat exchanger, when it will relight. This makes
the efficiency of the furnace drop SIGNIFICANTLY.

Heat can go into one of a couple places. Into the
house, into the cellar, up the chimney. When
efficiency drops SIGNIFIGANTLY, the heat is lost
some where.

So the burner shuts off, and the blower still runs.
How does this make the furnace less EFFICIENT? I
don't picture it. Shutting off the gas lowers
the efficiency? Really?

At church we have converted oil furnaces, which
now run NG. They have a high limit sensor in the
discharge air, when it gets to 110 or 120 it turns
off the flame. The three blowers keep running.

So, turning off the gas now and again makes the
efficiency of the furnace drop SIGNIFICANTLY?
How's that, again?

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

On Fri, 28 Feb 2014 22:29:59 -0500, Stormin Mormon
wrote:

On 2/28/2014 7:21 PM, Oren wrote:
On Fri, 28 Feb 2014 16:16:09 -0500, Stormin Mormon
wrote:

On 2/28/2014 3:59 PM, Oren wrote:
Hah. You Yanks really are in the dark ages,like a hundred years behind the
rest of civilisation.

But, after only a couple of hundred years we know how to spell
civilization.

Go figger


You using the F word again?

Fugetaboutit. I don't have explain it to you.


I'm going to repost some thing you
wrote last month.....

Okay. And then what?

--
"Never accuse a Soldier of being a Marine"

On 2/28/2014 11:04 PM, Oren wrote:
On Fri, 28 Feb 2014 22:29:59 -0500, Stormin Mormon
wrote:

On 2/28/2014 7:21 PM, Oren wrote:
On Fri, 28 Feb 2014 16:16:09 -0500, Stormin Mormon
wrote:

On 2/28/2014 3:59 PM, Oren wrote:
Hah. You Yanks really are in the dark ages,like a hundred years behind the
rest of civilisation.

But, after only a couple of hundred years we know how to spell
civilization.

Go figger


You using the F word again?

Fugetaboutit. I don't have explain it to you.


I'm going to repost some thing you
wrote last month.....

Okay. And then what?

And, then, you'll know that I really, really
mean it this time, not like last time.

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

On Fri, 28 Feb 2014 23:10:19 -0500, Stormin Mormon
wrote:

On 2/28/2014 11:04 PM, Oren wrote:
On Fri, 28 Feb 2014 22:29:59 -0500, Stormin Mormon
wrote:

On 2/28/2014 7:21 PM, Oren wrote:
On Fri, 28 Feb 2014 16:16:09 -0500, Stormin Mormon
wrote:

On 2/28/2014 3:59 PM, Oren wrote:
Hah. You Yanks really are in the dark ages,like a hundred years behind the
rest of civilisation.

But, after only a couple of hundred years we know how to spell
civilization.

Go figger


You using the F word again?

Fugetaboutit. I don't have explain it to you.


I'm going to repost some thing you
wrote last month.....

Okay. And then what?

And, then, you'll know that I really, really
mean it this time, not like last time.

Okay. And then what?

On Fri, 28 Feb 2014 22:35:34 -0500, Stormin Mormon
wrote:

On 2/28/2014 9:16 PM, wrote:

Closing a cold air return in an unheated room won't impact the combustion
air intake.

No, but it MAY cause the furnace to "short cycle" because the plenum
temperature will rize too high due to restricted air flow. This causes
the high limit switch to shut off the burner untill the blower sucks
the heat out of the heat exchanger, when it will relight. This makes
the efficiency of the furnace drop SIGNIFICANTLY.

Heat can go into one of a couple places. Into the
house, into the cellar, up the chimney. When
efficiency drops SIGNIFIGANTLY, the heat is lost
some where.
Up the stack. When a furnace short cycles it is running in the
in-efficient zone for more of the time. The heat goes up the stack
instead of into the house.

So the burner shuts off, and the blower still runs.
How does this make the furnace less EFFICIENT? I
don't picture it. Shutting off the gas lowers
the efficiency? Really?

At church we have converted oil furnaces, which
now run NG. They have a high limit sensor in the
discharge air, when it gets to 110 or 120 it turns
off the flame. The three blowers keep running.

So, turning off the gas now and again makes the
efficiency of the furnace drop SIGNIFICANTLY?
How's that, again?
see:
http://www.ehow.com/info_12081271_sh...-problems.html

http://www.ask.com/question/why-does...ing-on-and-off
http://books.google.ca/books?id=Vdxw...ciency&f=false

On Fri, 28 Feb 2014 21:16:31 -0500, wrote:

On Fri, 28 Feb 2014 21:13:19 +0000 (UTC), DerbyDad03
wrote:

If you close off your combustion air vents, you risk carbon monoxide
poisoning.

http://www.centralheating.org.uk/Cen...iler_Flues.htm

You need to catch up with the rest of the world.

Just so that there is no misunderstanding, my cold air returns are not my
"combustion air vents".

While I do draw combustion air from inside the house, it is drawn in right
at the furnace through a dedicated inlet pipe.

Closing a cold air return in an unheated room won't impact the combustion
air intake.
No, but it MAY cause the furnace to "short cycle" because the plenum
temperature will rize too high due to restricted air flow. This causes
the high limit switch to shut off the burner untill the blower sucks
the heat out of the heat exchanger, when it will relight. This makes
the efficiency of the furnace drop SIGNIFICANTLY.

Hmmm. That's a serious concern. Thank you. How short do you think
too short an ON portion of the cycle would be?

Also there should be some way to know if the furnace is turning off
because the thermostat reached the desired temp, OR becaues the high
limit switch turned it off. I realize now that I don't know why my
furnace turns off.

On Fri, 28 Feb 2014 22:35:34 -0500, Stormin Mormon
wrote:

On 2/28/2014 9:16 PM, wrote:

Closing a cold air return in an unheated room won't impact the combustion
air intake.

No, but it MAY cause the furnace to "short cycle" because the plenum
temperature will rize too high due to restricted air flow. This causes
the high limit switch to shut off the burner untill the blower sucks
the heat out of the heat exchanger, when it will relight. This makes
the efficiency of the furnace drop SIGNIFICANTLY.

Heat can go into one of a couple places. Into the
house, into the cellar, up the chimney. When
efficiency drops SIGNIFIGANTLY, the heat is lost
some where.

So the burner shuts off, and the blower still runs.
How does this make the furnace less EFFICIENT? I
don't picture it. Shutting off the gas lowers
the efficiency? Really?

At church we have converted oil furnaces, which

Was it before or after you bought them that they converted to Mormonism?

now run NG. They have a high limit sensor in the
discharge air, when it gets to 110 or 120 it turns
off the flame. The three blowers keep running.

So, turning off the gas now and again makes the
efficiency of the furnace drop SIGNIFICANTLY?
How's that, again?

Almost in the same way. I think?, that driving short distances and never
letting a car's engine warm up to proper operating temperature. In
the case of the furnace, it may get that warm, but because it turns off
soon, a higher percentage of the On time is at the lower temperature.

On Sat, 1 Mar 2014 00:03:01 +0000 (UTC), DerbyDad03
wrote:

micky wrote:

...snip...

When I say at the end I don't think it will change anything, I mean I
don't think it will change the character of an oil (or gas) fire to
either make the air in the house dirtier or make more carbon monoxide,
or something else I wouldn't like. DD3 says the same thing, iiuc.

Just for the record, I don't recall making any comments related to dirty
air or carbon monoxide.

I think I missed one word that changes everything. Sorry. People,
forget that I mentioned DD's name here.

But someone here in the last 15 years once said it would, and iirc no
one posted a disagreement.

On 2/27/2014 3:44 PM, Stormin Mormon wrote:
If I put a box over the heat vent in the kitchen and over the living
room, might not heat those rooms as much. Save a buck on energy?

Anyone tried this?

Gonna be below zero tonight, and windy. My heat bill will be up a
bit, or a lot.

I've see it cause the over temp sensor shut down more than one furnace
due to diminished airflow through the combustion chamber on NG fired
heating systems. When the temperature dropped to unusually low levels
here in Alabamastan, I left the rooms open to prevent the 7°F air from
freezing the pipes in the crawl space under "The Crotchety Old Fart's
Lair" because it's an older house with no insulation under the floors.
The extra cost to heat the open unoccupied rooms is much lower than the
cost of repairing freeze damage to the plumbing. ^_^

TDD

On 2/28/2014 11:14 PM, Oren wrote:
On Fri, 28 Feb 2014 23:10:19 -0500, Stormin Mormon
wrote:

On 2/28/2014 11:04 PM, Oren wrote:
On Fri, 28 Feb 2014 22:29:59 -0500, Stormin Mormon
wrote:

On 2/28/2014 7:21 PM, Oren wrote:
On Fri, 28 Feb 2014 16:16:09 -0500, Stormin Mormon
wrote:

On 2/28/2014 3:59 PM, Oren wrote:
Hah. You Yanks really are in the dark ages,like a hundred years behind the
rest of civilisation.

But, after only a couple of hundred years we know how to spell
civilization.

Go figger


You using the F word again?

Fugetaboutit. I don't have explain it to you.


I'm going to repost some thing you
wrote last month.....

Okay. And then what?

And, then, you'll know that I really, really
mean it this time, not like last time.

Okay. And then what?


And, then, you'll know that I really, really
mean it this time, not like last time.


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

On 3/1/2014 12:22 AM, wrote:
Closing a cold air return in an unheated room won't impact the combustion
air intake.

No, but it MAY cause the furnace to "short cycle" because the plenum
temperature will rize too high due to restricted air flow. This causes
the high limit switch to shut off the burner untill the blower sucks
the heat out of the heat exchanger, when it will relight. This makes
the efficiency of the furnace drop SIGNIFICANTLY.

Heat can go into one of a couple places. Into the
house, into the cellar, up the chimney. When
efficiency drops SIGNIFIGANTLY, the heat is lost
some where.
Up the stack. When a furnace short cycles it is running in the
in-efficient zone for more of the time. The heat goes up the stack
instead of into the house.
SM: So, the air handler blower is running, the gas is off, and the heat
is going up the stack, you say? I'd think the heat is going into the
building.


So the burner shuts off, and the blower still runs.
How does this make the furnace less EFFICIENT? I
don't picture it. Shutting off the gas lowers
the efficiency? Really?

At church we have converted oil furnaces, which
now run NG. They have a high limit sensor in the
discharge air, when it gets to 110 or 120 it turns
off the flame. The three blowers keep running.

So, turning off the gas now and again makes the
efficiency of the furnace drop SIGNIFICANTLY?
How's that, again?
see:
http://www.ehow.com/info_12081271_sh...-problems.html

SM: Says decresed efficiency, but doesn't explain
the process, and where the heat goes.

http://www.ask.com/question/why-does...ing-on-and-off
http://books.google.ca/books?id=Vdxw...ciency&f=false

SM: This page is not available, or you have exceeded
your limit for the day (my limit seems to be zero).

SM: I still don't see it, sorry.

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

On 3/1/2014 1:49 AM, micky wrote:
On Fri, 28 Feb 2014 22:35:34 -0500, Stormin Mormon
wrote:

On 2/28/2014 9:16 PM, wrote:

Closing a cold air return in an unheated room won't impact the combustion
air intake.

No, but it MAY cause the furnace to "short cycle" because the plenum
temperature will rize too high due to restricted air flow. This causes
the high limit switch to shut off the burner untill the blower sucks
the heat out of the heat exchanger, when it will relight. This makes
the efficiency of the furnace drop SIGNIFICANTLY.

Heat can go into one of a couple places. Into the
house, into the cellar, up the chimney. When
efficiency drops SIGNIFIGANTLY, the heat is lost
some where.

So the burner shuts off, and the blower still runs.
How does this make the furnace less EFFICIENT? I
don't picture it. Shutting off the gas lowers
the efficiency? Really?

At church we have converted oil furnaces, which

Was it before or after you bought them that they converted to Mormonism?

SM: After, sadly we were not able to find Mormon
furnaces. So, we gave them lots of natural gas,
and now they blow hot air.

now run NG. They have a high limit sensor in the
discharge air, when it gets to 110 or 120 it turns
off the flame. The three blowers keep running.

So, turning off the gas now and again makes the
efficiency of the furnace drop SIGNIFICANTLY?
How's that, again?

Almost in the same way. I think?, that driving short distances and never
letting a car's engine warm up to proper operating temperature. In
the case of the furnace, it may get that warm, but because it turns off
soon, a higher percentage of the On time is at the lower temperature.

SM: With a cold return closed, the furnace would
reach operating temp sooner, and spend more of
the day at operating temp. Not sure the two can
really be compared.

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

On Saturday, March 1, 2014 6:45:14 AM UTC-5, Stormin Mormon wrote:
On 3/1/2014 12:22 AM, wrote:

Closing a cold air return in an unheated room won't impact the combustion

air intake.



No, but it MAY cause the furnace to "short cycle" because the plenum

temperature will rize too high due to restricted air flow. This causes

the high limit switch to shut off the burner untill the blower sucks

the heat out of the heat exchanger, when it will relight. This makes

the efficiency of the furnace drop SIGNIFICANTLY.



Heat can go into one of a couple places. Into the

house, into the cellar, up the chimney. When

efficiency drops SIGNIFIGANTLY, the heat is lost

some where.

Up the stack. When a furnace short cycles it is running in the

in-efficient zone for more of the time. The heat goes up the stack

instead of into the house.

SM: So, the air handler blower is running, the gas is off, and the heat

is going up the stack, you say? I'd think the heat is going into the

building.





So the burner shuts off, and the blower still runs.

How does this make the furnace less EFFICIENT? I

don't picture it. Shutting off the gas lowers

the efficiency? Really?



At church we have converted oil furnaces, which

now run NG. They have a high limit sensor in the

discharge air, when it gets to 110 or 120 it turns

off the flame. The three blowers keep running.



So, turning off the gas now and again makes the

efficiency of the furnace drop SIGNIFICANTLY?

How's that, again?

see:

http://www.ehow.com/info_12081271_sh...-problems.html



SM: Says decresed efficiency, but doesn't explain

the process, and where the heat goes.



http://www.ask.com/question/why-does...ing-on-and-off

http://books.google.ca/books?id=Vdxw...ciency&f=false



SM: This page is not available, or you have exceeded

your limit for the day (my limit seems to be zero).



SM: I still don't see it, sorry.




A few things. In any correctly designed and installed forced air
furnace, you'd have to close down a lot more than one or two vents
to have the furnace shut down due to exceeding the high temp limit.
And in any recent vintage furnace, I don't think it's just going to
restart. More likely it's going to stay off with a fault code flashing.
If you choke off enough air flow, you also run the risk of burning out
the blower motor, depending on what kind it is.

As to the loss in efficiency, exactly how much you would lose IDK.
But you do lose efficiency if a furnace keeps going on and off instead
of running continually. For one thing, modern draft inducer models
run the blower to purge the system for like 30 secs before starting.
Whatever heat there was, it's blowing cold air through it for that period
and the heat is being vented outside with the air.
At the very least, you're losing that heat. Also, if it does recycle,
while it's sitting there cooling off from the over temp, some of that
heat is also flowing out the combustion air path, losing heat. Or being
lost to an unheated basement, etc.

On Sat, 01 Mar 2014 01:31:24 -0500, micky
wrote:

On Fri, 28 Feb 2014 21:16:31 -0500, wrote:

On Fri, 28 Feb 2014 21:13:19 +0000 (UTC), DerbyDad03
wrote:

If you close off your combustion air vents, you risk carbon monoxide
poisoning.

http://www.centralheating.org.uk/Cen...iler_Flues.htm

You need to catch up with the rest of the world.

Just so that there is no misunderstanding, my cold air returns are not my
"combustion air vents".

While I do draw combustion air from inside the house, it is drawn in right
at the furnace through a dedicated inlet pipe.

Closing a cold air return in an unheated room won't impact the combustion
air intake.
No, but it MAY cause the furnace to "short cycle" because the plenum
temperature will rize too high due to restricted air flow. This causes
the high limit switch to shut off the burner untill the blower sucks
the heat out of the heat exchanger, when it will relight. This makes
the efficiency of the furnace drop SIGNIFICANTLY.

Hmmm. That's a serious concern. Thank you. How short do you think
too short an ON portion of the cycle would be?

If the furnace shuts down while the thermostat is still calling for
heat, you have a problem, and it is short cycling.

Also there should be some way to know if the furnace is turning off
because the thermostat reached the desired temp, OR becaues the high
limit switch turned it off. I realize now that I don't know why my
furnace turns off.
What kind of thermostat? If it is an electronic digital stat it
usually has an indicator telling when it is calling for heat.

Mine ( a 2 stage furnace - high stage really too big for the house)
will occaisionally short cycle if it goes on high.

On Sat, 01 Mar 2014 06:45:14 -0500, Stormin Mormon
wrote:

On 3/1/2014 12:22 AM, wrote:
Closing a cold air return in an unheated room won't impact the combustion
air intake.

No, but it MAY cause the furnace to "short cycle" because the plenum
temperature will rize too high due to restricted air flow. This causes
the high limit switch to shut off the burner untill the blower sucks
the heat out of the heat exchanger, when it will relight. This makes
the efficiency of the furnace drop SIGNIFICANTLY.

Heat can go into one of a couple places. Into the
house, into the cellar, up the chimney. When
efficiency drops SIGNIFIGANTLY, the heat is lost
some where.
Up the stack. When a furnace short cycles it is running in the
in-efficient zone for more of the time. The heat goes up the stack
instead of into the house.
SM: So, the air handler blower is running, the gas is off, and the heat
is going up the stack, you say? I'd think the heat is going into the
building.


So the burner shuts off, and the blower still runs.
How does this make the furnace less EFFICIENT? I
don't picture it. Shutting off the gas lowers
the efficiency? Really?

At church we have converted oil furnaces, which
now run NG. They have a high limit sensor in the
discharge air, when it gets to 110 or 120 it turns
off the flame. The three blowers keep running.

So, turning off the gas now and again makes the
efficiency of the furnace drop SIGNIFICANTLY?
How's that, again?
see:
http://www.ehow.com/info_12081271_sh...-problems.html

SM: Says decresed efficiency, but doesn't explain
the process, and where the heat goes.

http://www.ask.com/question/why-does...ing-on-and-off
http://books.google.ca/books?id=Vdxw...ciency&f=false

SM: This page is not available, or you have exceeded
your limit for the day (my limit seems to be zero).

SM: I still don't see it, sorry.
OK Stormey, I'll try to explain it in simple terms.

You start the cold furnace, and it has to warm up the stack to get a
good draft going (unless it is a high efficiency burner - where you
get a forced draft, but it still needs to warm up) When it gets up to
operating temp, it is running at top effieniency. It warms up the heat
exchanger and plenum, and at a certain plenum temperature the blower
comes on to extract the heat from the heat exchanger and move it
through the house. The Delta T between the return air and the heat
exchanger temperature affects the efficiency of heat transfer - the
goal is to keep the delta T (temperature difference) between the
return air and the heat exchanger in the "sweet spot" where the
maximum heat is extracted from the exchanger and delivered to the
house. Now, if the airflow cannot extract enough heat, the heat
exchanger/plenum gets too hot, and for safety reasons the furnace
shuts down (short cycles). Now the firebox/burner/stack go into
cooldown mode along with the heat exchanger. When the heat exchanger
drops down to the "reset" temperature, the furnace refires and starts
the cycle all over again. Much of this time the delta T between the
exchanger and the return air is sub-optimal - dropping the heat
exchanger efficiency. - and the furnace starts up in it's lower
efficiency range untill it warms up again. Low airflow causes the heat
exchanger/plenum temp to go above limits again, and the (short) cycle
repeats itself. During this whole cycle, the efficiency is less than
optimal. When the airflow is not removing the heat from the exchanger
efficiently, heat goes up the stack.


In a properly operating system, when the furnace gets the plenum up to
temperature and the blower comes on, the correct amount of air passes
the exchanger to transfer enough heat from the exchanger to keep the
delta T in the "sweet spot" where maximum heat energy is removed from
the heat exchanger, and the minimum required heat escapes up the
stack. On variable speed blowers, the system is set up for a specific
temperature size across the heat exchanger. On my furnace it is spec'd
at between 30-60 degree F temperature rize across the heat exchanger
with 28000-40000btu output
The bigger model of this furnace is 45-75F at 89-72000 btu output.
My blower is set at about 650 CFM

On 3/1/2014 1:42 PM, wrote:
OK Stormey, I'll try to explain it in simple terms.

You start the cold furnace, and it has to warm up the stack to get a
good draft going (unless it is a high efficiency burner - where you
get a forced draft, but it still needs to warm up) When it gets up to
operating temp, it is running at top effieniency. It warms up the heat
exchanger and plenum, and at a certain plenum temperature the blower
comes on to extract the heat from the heat exchanger and move it
through the house. The Delta T between the return air and the heat
exchanger temperature affects the efficiency of heat transfer - the
goal is to keep the delta T (temperature difference) between the
return air and the heat exchanger in the "sweet spot" where the
maximum heat is extracted from the exchanger and delivered to the
house. Now, if the airflow cannot extract enough heat, the heat
exchanger/plenum gets too hot, and for safety reasons the furnace
shuts down (short cycles). Now the firebox/burner/stack go into
cooldown mode along with the heat exchanger. When the heat exchanger
drops down to the "reset" temperature, the furnace refires and starts
the cycle all over again. Much of this time the delta T between the
exchanger and the return air is sub-optimal - dropping the heat
exchanger efficiency. - and the furnace starts up in it's lower
efficiency range untill it warms up again. Low airflow causes the heat
exchanger/plenum temp to go above limits again, and the (short) cycle
repeats itself. During this whole cycle, the efficiency is less than
optimal. When the airflow is not removing the heat from the exchanger
efficiently, heat goes up the stack.


In a properly operating system, when the furnace gets the plenum up to
temperature and the blower comes on, the correct amount of air passes
the exchanger to transfer enough heat from the exchanger to keep the
delta T in the "sweet spot" where maximum heat energy is removed from
the heat exchanger, and the minimum required heat escapes up the
stack. On variable speed blowers, the system is set up for a specific
temperature size across the heat exchanger. On my furnace it is spec'd
at between 30-60 degree F temperature rize across the heat exchanger
with 28000-40000btu output
The bigger model of this furnace is 45-75F at 89-72000 btu output.
My blower is set at about 650 CFM


At high limit, the delta T will be higher than spec,
so more heat goes into the house. Then, it goes through
the cycle. I can't see this being a major loss of
efficiency.

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

In a properly operating system, when the furnace gets the plenum up to

temperature and the blower comes on, the correct amount of air passes

the exchanger to transfer enough heat from the exchanger to keep the

delta T in the "sweet spot" where maximum heat energy is removed from

the heat exchanger, and the minimum required heat escapes up the

stack. On variable speed blowers, the system is set up for a specific

temperature size across the heat exchanger. On my furnace it is spec'd

at between 30-60 degree F temperature rize across the heat exchanger

with 28000-40000btu output

The bigger model of this furnace is 45-75F at 89-72000 btu output.

My blower is set at about 650 CFM


There is no "sweet spot" for the heat exchanger efficiency. Setting the blower on HIGH blowing more air over the heat exchanger will always be more efficient then lass air.

It's only a sweet spot in terms of comfort and not feeling a draft in your home, not in terms of heat exchanger efficiency.