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Posted by .p.jm on February 9, 2008, 1:35 pm
On Wed, 06 Feb 2008 02:28:49 -0500, .p.jm@see_my_sig_for_address.com
wrote:
This was not me!!
show/hide quoted text
>On Mon, 7 Jan 2008 14:13:24 -0800 (PST), "Daniel J. Stern"
>>We have gas-fired central heat with A/C in our old 2-story (+
>>basement) house. 3-year-old Lennox air handler is in the basement.
>>This house has been badly abused in the past, and ductwork has been
>>mutilated. Air return capacity is grossly insufficient: the one and
>>only air return is on the main floor, and it is the ~4" x 10" size of
>>a regular heat register. There are eight supply registers throughout
>>the house, nine if we count the one in the basement, some of which are
>>oversize, so obviously one small register hole just isn't enough. The
>>return duct goes audibly into vacuum when the furnace blower turns on
>>(metal walls of the duct "pop"). To alleviate this condition, I
>>removed the blockoff plate from the return duct in the basement. This
>>plate covered where a humidifier used to be installed. I put some wire
>>mesh over the hole and some spun-fibre filter batting over the mesh.
>>This relieved the vacuum condition on the return duct, but is probably
>>less than optimal (basement is smelly/mouldy/dusty) and may be against
>>code (distribution air intake in the same space as combustion taking
>>place -- don't know if that's problematic or not.)
>>It occurs to me a flex duct could be run from the return duct (using
>>the blockoff plate hole) to a pass-through in an unused door from the
>>basement to outside, and a rodent/leaf/waterproof exterior air intake
>>could be put on the outside. This would take supply air from outside
>>the house and duct it to the air handler. Now here's the question:
>>What would be the effect on system efficiency by doing so? I can think
>>of two possible answers: Either the very cold outside air would take
>>much more energy to heat up to household temperature, increasing the
>>cost of running the system, or the greater temperature differential
>>between the fire and air sides of the heat exchanger would mean more
>>heat transfer to the supply air, reducing the amount of heat wasted up
>>the flue and not significantly increasing fuel consumption to provide
>>a given household ambient temperature. Obviously the reverse (cool/
>>warm) of either situation would apply during air conditioning season.
>>So...which is it?
>>Please and thank you,
>>-DS
> Save your 'magic words'. The only 'magic words' you have any
>use for right now are 'Heavenly Father, we commend the spirit of the
>dearly departed unto your care'.
> Congratulations ! You have created a situation that is LIKELY
>TO KILL SOMEONE, and if it's YOU, you get your very own DARWIN
>AWARD !!!!!
> Bad news - they generally arrive a bit too late for you to
>enjoy.
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
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>>We have gas-fired central heat with A/C in our old 2-story (+
>>basement) house. 3-year-old Lennox air handler is in the basement.
>>This house has been badly abused in the past, and ductwork has been
>>mutilated. Air return capacity is grossly insufficient: the one and
>>only air return is on the main floor, and it is the ~4" x 10" size of
>>a regular heat register. There are eight supply registers throughout
>>the house, nine if we count the one in the basement, some of which are
>>oversize, so obviously one small register hole just isn't enough. The
>>return duct goes audibly into vacuum when the furnace blower turns on
>>(metal walls of the duct "pop"). To alleviate this condition, I
>>removed the blockoff plate from the return duct in the basement. This
>>plate covered where a humidifier used to be installed. I put some wire
>>mesh over the hole and some spun-fibre filter batting over the mesh.
>>This relieved the vacuum condition on the return duct, but is probably
>>less than optimal (basement is smelly/mouldy/dusty) and may be against
>>code (distribution air intake in the same space as combustion taking
>>place -- don't know if that's problematic or not.)
>>It occurs to me a flex duct could be run from the return duct (using
>>the blockoff plate hole) to a pass-through in an unused door from the
>>basement to outside, and a rodent/leaf/waterproof exterior air intake
>>could be put on the outside. This would take supply air from outside
>>the house and duct it to the air handler. Now here's the question:
>>What would be the effect on system efficiency by doing so? I can think
>>of two possible answers: Either the very cold outside air would take
>>much more energy to heat up to household temperature, increasing the
>>cost of running the system, or the greater temperature differential
>>between the fire and air sides of the heat exchanger would mean more
>>heat transfer to the supply air, reducing the amount of heat wasted up
>>the flue and not significantly increasing fuel consumption to provide
>>a given household ambient temperature. Obviously the reverse (cool/
>>warm) of either situation would apply during air conditioning season.
>>So...which is it?
>>Please and thank you,
>>-DS
> Save your 'magic words'. The only 'magic words' you have any
>use for right now are 'Heavenly Father, we commend the spirit of the
>dearly departed unto your care'.
> Congratulations ! You have created a situation that is LIKELY
>TO KILL SOMEONE, and if it's YOU, you get your very own DARWIN
>AWARD !!!!!
> Bad news - they generally arrive a bit too late for you to
>enjoy.