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Old 01-24-2009, 06:47 AM   #76
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Confirming correct gas pressure for new furnace


The heat exchangers temp, is always higher then the air temp(presuming the furnace is running, and working correctly ).

The surface temp of the HX increases more then 10 when you increase the temp rise 10.

2 forms of heat come from a hot air furnace(actually 3).

A. Conduction.
B. Radiant.
C. Convection.

The lower temp rise, means the HX temp is cooler so that you are receiving less heat(BTUs) from radiant heat(internal jacket temp is cooler), and more heat through conduction(air contact with HX surface).

The higher temp rise means your getting more heat(BTUs) from radiant(internal jacket temp is much higher), and less from conduction(air contact with HX surface). Which means the HX temp is higher. Although still providing the same amount of heat(BTUs) to the air. (To an extent, after you slow the air so much, you actually lose heat transfer efficiency).

You may not have an electric range.

But, if you ever get a chance, do a little experiement.

Fill a kettle/pot with cold water, set it down near the range.
Turn a burner to high. Wait and watch for it's element to glow red.
After its glowing red, put the pot/kettle of water on it for a minute or 2.

Then remove it and look at the burner/element.
Its not glowing red anymore.

Without the pot/kettle on it, over 90% of its heat was in the form of radiant.
With the pot/kettle on it, over 90% of its heat was from conduction.

Same amount of heat BTU wise.

But, which way was the element actually hotter.
And which way do you think is more harmfull to the elecment, as far as shortening its life span.

A furnace's heat exchanger life span, and performance, is a balance of maintaining the right proportion of radiant and conduction heat transfer.

At 100 return air temp, and 65 temp rise, the heat exchanger, is cooler then at 70 return temp, and 95 rise.

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Old 01-24-2009, 07:58 AM   #77
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Confirming correct gas pressure for new furnace


Ok, so Been took it in stride. Just shows you what a class act he is.
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Old 01-24-2009, 08:36 AM   #78
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Confirming correct gas pressure for new furnace


Quote:
Originally Posted by beenthere View Post
The heat exchangers temp, is always higher then the air temp(presuming the furnace is running, and working correctly ).

The surface temp of the HX increases more then 10 when you increase the temp rise 10.

2 forms of heat come from a hot air furnace(actually 3).

A. Conduction.
B. Radiant.
C. Convection.

The lower temp rise, means the HX temp is cooler so that you are receiving less heat(BTUs) from radiant heat(internal jacket temp is cooler), and more heat through conduction(air contact with HX surface).

The higher temp rise means your getting more heat(BTUs) from radiant(internal jacket temp is much higher), and less from conduction(air contact with HX surface). Which means the HX temp is higher. Although still providing the same amount of heat(BTUs) to the air. (To an extent, after you slow the air so much, you actually lose heat transfer efficiency).

You may not have an electric range.

But, if you ever get a chance, do a little experiement.

Fill a kettle/pot with cold water, set it down near the range.
Turn a burner to high. Wait and watch for it's element to glow red.
After its glowing red, put the pot/kettle of water on it for a minute or 2.

Then remove it and look at the burner/element.
Its not glowing red anymore.

Without the pot/kettle on it, over 90% of its heat was in the form of radiant.
With the pot/kettle on it, over 90% of its heat was from conduction.

Same amount of heat BTU wise.

But, which way was the element actually hotter.
And which way do you think is more harmfull to the elecment, as far as shortening its life span.

A furnace's heat exchanger life span, and performance, is a balance of maintaining the right proportion of radiant and conduction heat transfer.

At 100 return air temp, and 65 temp rise, the heat exchanger, is cooler then at 70 return temp, and 95 rise.
Been, great explanation.

V
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Old 01-24-2009, 08:46 AM   #79
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Confirming correct gas pressure for new furnace


Quote:
Originally Posted by beenthere View Post
The heat exchangers temp, is always higher then the air temp(presuming the furnace is running, and working correctly ).

The surface temp of the HX increases more then 10 when you increase the temp rise 10.

2 forms of heat come from a hot air furnace(actually 3).

A. Conduction.
B. Radiant.
C. Convection.

The lower temp rise, means the HX temp is cooler so that you are receiving less heat(BTUs) from radiant heat(internal jacket temp is cooler), and more heat through conduction(air contact with HX surface).

The higher temp rise means your getting more heat(BTUs) from radiant(internal jacket temp is much higher), and less from conduction(air contact with HX surface). Which means the HX temp is higher. Although still providing the same amount of heat(BTUs) to the air. (To an extent, after you slow the air so much, you actually lose heat transfer efficiency).

You may not have an electric range.

But, if you ever get a chance, do a little experiement.

Fill a kettle/pot with cold water, set it down near the range.
Turn a burner to high. Wait and watch for it's element to glow red.
After its glowing red, put the pot/kettle of water on it for a minute or 2.

Then remove it and look at the burner/element.
Its not glowing red anymore.

Without the pot/kettle on it, over 90% of its heat was in the form of radiant.
With the pot/kettle on it, over 90% of its heat was from conduction.

Same amount of heat BTU wise.

But, which way was the element actually hotter.
And which way do you think is more harmfull to the elecment, as far as shortening its life span.

A furnace's heat exchanger life span, and performance, is a balance of maintaining the right proportion of radiant and conduction heat transfer.

At 100 return air temp, and 65 temp rise, the heat exchanger, is cooler then at 70 return temp, and 95 rise.

I said it before and I'll say it again. Beenthere is in a class by himself

Thanks again Beenthere for furthering my production of additional brain cells. I really enjoy learning about this stuff and I will not be deterred by those that would rather I spent my free time as they do....watching re-runs of "Seinfield".....
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Old 01-24-2009, 08:48 AM   #80
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Confirming correct gas pressure for new furnace


Quote:
Originally Posted by hvaclover View Post
Looked like you were continuing the conversation to me.
It's expected and usual to redirect the question /conversation if you are addressing the whole board.

No harm...no foul..

Key1
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Old 01-24-2009, 08:51 AM   #81
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Confirming correct gas pressure for new furnace


Quote:
Originally Posted by hvaclover View Post
Ok, so Been took it in stride. Just shows you what a class act he is.
I still have no idea what you are talking about.....an actually I probally don't want to know.

Remember the glass can always be perceived as half full or half empty. It is up to the interpreter to decide which.

Key1
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Old 01-24-2009, 11:14 AM   #82
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Confirming correct gas pressure for new furnace


Quote:
Originally Posted by key1cc View Post
I said it before and I'll say it again. Beenthere is in a class by himself

Thanks again Beenthere for furthering my production of additional brain cells. I really enjoy learning about this stuff and I will not be deterred by those that would rather I spent my free time as they do....watching re-runs of "Seinfield".....
Key1
Wait till you get my $7,800.00 bill for first Semester Tuition.
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Old 01-24-2009, 11:49 AM   #83
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Confirming correct gas pressure for new furnace


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Wait till you get my $7,800.00 bill for first Semester Tuition.

Check is in the mail ....
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Old 01-24-2009, 11:49 AM   #84
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Confirming correct gas pressure for new furnace


Plus $6800 for Yuri. LOL. Should have never given out that meter clocking info. LOL

Last edited by yuri; 01-24-2009 at 11:51 AM.
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Old 01-24-2009, 01:11 PM   #85
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Confirming correct gas pressure for new furnace


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Last edited by kennzz05; 01-24-2009 at 01:18 PM.
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Old 01-24-2009, 03:40 PM   #86
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Confirming correct gas pressure for new furnace


Quote:
Originally Posted by key1cc View Post
I still have no idea what you are talking about.....an actually I probally don't want to know.

Remember the glass can always be perceived as half full or half empty. It is up to the interpreter to decide which.

Key1

Half way? You sayin' the new president is half white?
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Old 01-24-2009, 03:46 PM   #87
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Confirming correct gas pressure for new furnace


Quote:
Originally Posted by kennzz05 View Post
zzzzzzzzzzzzzzzzzzzzzzzzzzzz


































































































































zzzzzzzzzzzzzzzzzzzz














































































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Old 01-25-2009, 11:08 AM   #88
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I disagree with zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz-----------This was better than reading my playboy-LOL--seriously
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Old 01-25-2009, 12:07 PM   #89
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I disagree with zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz-----------This was better than reading my playboy-LOL--seriously
Good! it's going to get much better if I ever get my tools.

In the mean time a link for your continued reading pleasures.

http://www.helpinaflash.com/House-Pr...t-Transfer.cfm

For those who prefer to read this thread as a sleep inducer rather than count sheep....
Glad we can save you a few pennies off your sleeping pills...

Key1

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