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High Efficiency gas furnace - return air temperature bubbabubbs 01-19-2007
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Posted by Tom The Great on January 20, 2007, 10:30 am
On 18 Jan 2007 21:12:17 -0800, bubbabubbs@yahoo.com wrote:

>The unit in question is Goodman GMV9509050XBA gas furnace (95% eff.,
>90,000 BTU.)
>It says in the Installation Instructions (page 7, Location Requirements
>& Considerations) that the following must be observed:
>
>"The temperature of the return air entering the furnace is between 55F
>and 100F when the furnace is heating."
>
>I am curious why the 55F requirement. I mean, when I'm not in the
>house, I would like to set the temp as low as possible in order to save
>on my heating bill. I think I could otherwise set it as low as 45-50F
>and still keep the water pipes from freezing. But I wonder why I'm not
>supposed to go below 55F. What could happen? Could the unit get damaged
>and why?
>
>Thanks
>
>P.S. I'm in the Denver, CO area - 5,300 ft altitude, if that matters.


Now are you reading that right? Is that a statement of general
operation, or an actual requirement?

tom @ www.YourMoneySavingTips.com




Posted by Redcrosse on January 21, 2007, 12:28 pm
It is my understanding that if the return air temperature is too low
the
heat exchanger can be "shocked"--that is to say it may expand and
contract
beyond design limits and fail.


Posted by AKS on January 21, 2007, 3:13 pm
Any metal will expand and contract with change of temperature
but I do not believe that this problem occurs in low temp.
residential furnaces however anything is possible
Dido

> It is my understanding that if the return air temperature is too low
> the
> heat exchanger can be "shocked"--that is to say it may expand and
> contract
> beyond design limits and fail.
>



Posted by Bob_Loblaw on January 21, 2007, 8:49 pm

> Any metal will expand and contract with change of temperature
> but I do not believe that this problem occurs in low temp.
> residential furnaces however anything is possible
> Dido


So now you're telling us that if the air entering the furnace is too cold,
it can crack the exchanger!
WOW!!
And all this time , I thought furnaces were designed to take cold air and
warm it up!
How many times have you experienced this, Dildo, or is experience the wrong
word to use with you?



--
Respectfully, Bob

Posted by AKS on January 25, 2007, 8:26 am

>
>> Any metal will expand and contract with change of temperature
>> but I do not believe that this problem occurs in low temp.
>> residential furnaces however anything is possible
>> Dido
>
>
> So now you're telling us that if the air entering the furnace is too cold,
> it can crack the exchanger!
> WOW!!
> And all this time , I thought furnaces were designed to take cold air and
> warm it up!
> How many times have you experienced this, Dildo, or is experience the
> wrong
> word to use with you?

> Respectfully, Bob



BOB??? You are to stupid for any one to respond to you postings
Dido



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