On 3/1/2014 6:36 PM, wrote:




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.


You're not suggesting that Clare is mistaken?

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

On Saturday, March 1, 2014 6:03:05 PM UTC-5, Stormin Mormon wrote:
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

.


You have it backwards. With a lot of the air handler air flow blocked
off, you have less air moving, the air in the plenum get *hotter* and
the temperature delta across the heat exchanger is lower, ie the plenum
temp is closer to the temp of the combustion gases. Hence, you recover
less heat and more of it goes out the exhaust.

Also as pointed out previously, if the furnace then kicks off and
recycles on and off due to the high limit being hit, during the
period it's cooling down, most of that heat is being lost up the vent,
or could be lost to an unfinished basement, attic, etc. I think that's
largely a moot point, because I believe any modern furnace is going
to trip and stay off with a fault code if the high limit is exceeded.
But if it does continue to cycle on and off, no question you're taking
a hit on energy loss.

On Sat, 01 Mar 2014 06:48:01 -0500, Stormin Mormon
wrote:

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

FTR, I thought we were talking about closing the warm air supply to some
rooms, but actually I don't think there is much difference.

reach operating temp sooner, and spend more of
the day at operating temp.

But they don't run all day. It might be 10 or 20 minutes. Yeah I see
your point that, assuming as was said that they warm faster, they get to
operating temp sooner than normal, but they might then zoom though that
temp range on to overheated soon thereafter.

Not sure the two can
really be compared.

I think they can but maybe there is no general rule. Maybe each similar
furnace setup is the same but ....

Well I don't know what the but is, but I've been bothered since
yesterday, per my previous post, wondering if that was why my furnace
was turning off. In the short period between replacing the igniton
transformer and having the next problem, I was sitting at my computer in
the room next to the furnace and for about an hour I logged when it
started, when the blower started, when the fire stopped, and when the
blower stopped. The notes are somewhere in my Agent outbox so I have
to find them and read them.

The rest of this post is about my 1979 furnace and may not interest most
people, but though many things have changed over the years, I doubt the
final actions described here of the control panel, etc. have changed.

I've also been trying some more to understand the furance wiring. There
are a couple omissions to the wiring diagram (2 resistors), and one or
two more things** I haven't figured out yet, but most I do understand
and when the heat limit switch opens, that interrupts the 120 volt black
wire to the furnace. which will turn off the burner motor, the ignition
transformer, and the control board power transformer (which powers the
furnace relay so that too turns off the furnace) . The fan wiring I
find complicated but I don't think the fan turns off because it's needed
to cool off the plenum etc. which we just said had overheated. Anyhow,
after the house reached 168, the furnace never ran for more than 20
minutes iirc and that started to worry me.

Since I've had trouble with the control panel, what I've been doing is
turning the furnace on by hand (with a stick*** holding down the relay
armature) for 2 or 3 hours when I wake up in the morning, and for 2 or 3
hours just before I got to bed. (Less time during the couple days it
was warmer out) I get the second floor of the house up to 178 or even
180 before I got to bed (where I often listen to the radio for a couple
hours and then sleep 8 hours) and it's 164 to 168 in the morning.
Under the covers it's always warm enough, but a couple days, I've had to
dress quickly and go turn the furnace on.

If my furnace could overheat in 20 minutes, surely it would overheat in
3 hours and the high limit swtich would turn off the whole furnace.
But it doesn't. I have to turn it off by taking the stick out. So it
must not be overheating.


***The stick was originally used to post an illegal advertising poster
on public land. Baltimore County law now allows anyone to remove such
signs. Many are held up by wire things, but when it's wood, I save the
wood. About 2 feet long by 1 by 1/2" with a point at one end.

**Things I don't yet understand about the schematic. The switch that
turns the furnace off when there is no flame (or maybe too much black
smoke??) has four wires going into it, but the schematic shows nothing
about how they are connected inside -- it's a black box -- and that
makes it hard to understnd the main relay's operation, since two of
those four wires are connected straight to the main relay coil. Also
the fan relay, which is in the fan & limit control enclosure, I think, I
have just started to figure out. The schematic does not use the same
exact symbols that radio and tv schematics do. I think I've found a
double throw switch but I'm not sure. (Maybe I'll post the diagrams)
It also doesn't match my own fan, which has 3 speeds but only one is
connected, the same fan speed for everything. This one from the web for
my model may have high speed for AC and low or medium for heat.

It also appears that 24 volts are provided to close the main relay, when
the thermostat calls for heat, but maybe that's lowered to 12 volts to
keep the relay closed once it has closed. Can't tell because of the
black box.


I have also found that sometimes when the house is cold enough that the
thermostat should call for heat, when I start to close the relay by
hand, when the armature is half-way there, it's pulled shut
magnetically****. But it didn't shut without my help. That goes
with something I think you said, that there's a problem with the main
relay coil. So I've decided to replace the control board (including
the main relay coil) first and worry about the thermostat later.

****Other times when the house is cold, there is no magnetism in the
relay. How can that be? Maybe that's a problem with the thermostat or
maybe it's gremlins.

(ONE DAY WHEN I GUESS I HAD THE STICK just right, the furnace went on
and off by itself for 24 hours or so, and the house was always 68. I
guess the stick wasn't holding the armature closed but it was holding it
close enough to the relay coil that the coil could pull it the rest of
the way. Nothing else makes sense.)

I also remembered that my thermostat is electronic or semi-electronic,
not like the round honeywell thermostat that was used initially in 1979
and is in the schematic, and disconnecting the stat and expecting to
find zero ohms across the red and white wires when the house is cold
might be wrong. Maybe it needs its 24 volts to work right.

On Sat, 01 Mar 2014 13:16:42 -0500, wrote:

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.

Well, right now I'm not using the thermostat, but now that this issue
has come up, I'm going to up the priority of the control board
replacement and I should know soon.

Although with a day to think about it, it seems to me from theory and
looking at the wiring diagram for my furnace installation that if the
high limit switch opens, the furnace would shut down, except for the
blower needed to cool it off, and it never shuts down until I do it
manually, even after 3 hours. That's certainly not a short cycle.

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.

I have maybe the first residential setback thermostat sold, from 1984
maybe. It's electronic or semielectronic, The clock is digital but the
time and temp settings are mechanical switches. Anyhow, no indicator.

But when I replace the control board on the furnace, I'll put in a
couple wires that extend beyond the furnace, so I'll be able to use a
voltmeter to check without having to get my hands in among hot wires.


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

On Sat, 1 Mar 2014 05:48:54 -0800 (PST), "
wrote:

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.

Isn't the loss of efficiency in large part because of unburned fuel,
because of the wrong temperature for the fire chamber. And it's the
unburned fuel, gas or oil, that goes up the chimney.

In the case of oil, with a cracked heat exchanger and apparently even
with a good heat exchanger, doesn't the unburned oil get on the walls
and ceilings and anything else that attracts it, and make the house
dirty. And if that's not true all the time because of a misadjusted
furnace, it's stil true during the startup time when the firebox is not
hot enough. Isn't that what they're referring to when they say oil is
dirtier than gas?



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.

Why does it blow it outside? Why not inside? Were my old furnace to
run the blower before ignition, it would just blow the heat into the
heating vents and out the other end if it ran long enough.


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 Sunday, March 2, 2014 11:32:14 AM UTC-5, micky wrote:
On Sat, 1 Mar 2014 05:48:54 -0800 (PST), "

wrote:



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.



Isn't the loss of efficiency in large part because of unburned fuel,

because of the wrong temperature for the fire chamber. And it's the

unburned fuel, gas or oil, that goes up the chimney.

No, because it has little effect on the fuel burning. Close to 100%
of the fuel is burned, no matter what.






In the case of oil, with a cracked heat exchanger and apparently even

with a good heat exchanger, doesn't the unburned oil get on the walls

and ceilings and anything else that attracts it, and make the house

dirty.

Irrelevant.


And if that's not true all the time because of a misadjusted

furnace, it's stil true during the startup time when the firebox is not

hot enough. Isn't that what they're referring to when they say oil is

dirtier than gas?







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.



Why does it blow it outside? Why not inside?

Because combustion gases go outside, not into the house.


Were my old furnace to

run the blower before ignition, it would just blow the heat into the

heating vents and out the other end if it ran long enough.



Really? It blew combustion gasses into the house? That explains
a lot.

You obviously don't understand the difference between an air handler
blower and an inducer blower. And I've never seen a furnace run the
air handler blower *before* ignition. Everyone has a delay, so that
it doesn't blow cold air.

On Sun, 02 Mar 2014 11:32:14 -0500, micky
wrote:

On Sat, 1 Mar 2014 05:48:54 -0800 (PST), "
wrote:

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.

Isn't the loss of efficiency in large part because of unburned fuel,
because of the wrong temperature for the fire chamber. And it's the
unburned fuel, gas or oil, that goes up the chimney.

In the case of oil, with a cracked heat exchanger and apparently even
with a good heat exchanger, doesn't the unburned oil get on the walls
and ceilings and anything else that attracts it, and make the house
dirty. And if that's not true all the time because of a misadjusted
furnace, it's stil true during the startup time when the firebox is not
hot enough. Isn't that what they're referring to when they say oil is
dirtier than gas?



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.

Majority of furnaces in todays housing stock are oversized, so
restricting the airflow can very easily overheat the plenum. And
restricting airflow REDUCES the load on the blower motor, so you are
unlikely to burn out the blower motor.

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.

Why does it blow it outside? Why not inside? Were my old furnace to
run the blower before ignition, it would just blow the heat into the
heating vents and out the other end if it ran long enough.

You are talking the "combustion chamber". The combustion chamber is
purged to make sure there is not an explosive mixture of gas and air
in the chamber when the ignitor comes on. . You most certainly do NOT
want to purge the combustion chamber to the "conditioned space" - it
MUST be purged to the outside.. This is NOT the blower that circulates
the heat in your house. You must not have ever seen a gas furnace
newer than about 20 years.


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.
The air circulation blower does not EVER move combustion air,

On Sunday, March 2, 2014 5:16:47 PM UTC-5, wrote:


Majority of furnaces in todays housing stock are oversized, so

restricting the airflow can very easily overheat the plenum.

Over sizing the *system* in a house has nothing to do with
the ability to overheat the system. If you install a furnace that
is too big for the *sytem*, then yes it could overheat easier if
you restrict the air flow. But good grief. Stormin is talking about
shutting off a couple of vents. I've never heard of that causing
a furnace to go over temp and shut down. And if it does, something
more is wrong than closing a couple of vents.


And

restricting airflow REDUCES the load on the blower motor, so you are

unlikely to burn out the blower motor.



You might want to re-think that in view of that fact that a lot
of new furnaces have ECM motors that are designed to maintain a
given CFM of airflow.






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.



Why does it blow it outside? Why not inside? Were my old furnace to

run the blower before ignition, it would just blow the heat into the

heating vents and out the other end if it ran long enough.



You are talking the "combustion chamber". The combustion chamber is

purged to make sure there is not an explosive mixture of gas and air

in the chamber when the ignitor comes on. . You most certainly do NOT

want to purge the combustion chamber to the "conditioned space" - it

MUST be purged to the outside.. This is NOT the blower that circulates

the heat in your house. You must not have ever seen a gas furnace

newer than about 20 years.





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.

The air circulation blower does not EVER move combustion air,

Can't you follow a thread? Nothing I said ever stated or implied
that the air handler moves combustion air. Yet you're replying
to the part that I wrote.

posted for all of us...

And I know how to SNIP

OK Stormey, I'll try to explain it in simple terms.


At lot of good info snipped but wasted on Stumped.

Claire, I hate to say it but this has been explained to Stumped MANY times
before. I urge all posters that haven't kill filed him yet to read his past
postings and responses. Some border on the deadly. Prove it to yourself.

--
Tekkie

Temps below zero F, tonight, with wind chill
even below that. Should I leave a faucet
dripping?

Should I cover a heat vent or two?


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

On Mon, 03 Mar 2014 22:23:10 -0500, Stormin Mormon
wrote:

Temps below zero F, tonight, with wind chill
even below that. Should I leave a faucet
dripping?

Should I cover a heat vent or two?
Rent a propane powered "salamander" heater and blast it under your
"redneck bungalow" You won't need your bunny slippers to go to the
john, and you won't freeze your pipes.

On 3/4/2014 8:02 PM, wrote:
Should I cover a heat vent or two?
Rent a propane powered "salamander" heater and blast it under your
"redneck bungalow" You won't need your bunny slippers to go to the
john, and you won't freeze your pipes.


Rent a heater.
Pay for fuel oil.
Pay for electric.
Heat goes out from the skirting.

So, tell me about savings?

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