| Re: [GMCnet] Furnace Boost fan [message #67185] |
Fri, 11 December 2009 11:24  |
rallymaster
Messages: 662
Registered: February 2004
Location: North Plains, ORYGUN
Karma: -4
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Senior Member |
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I used black ABS pipe of the appropriate size to carry the air around the
coach. Its thickness provides a tiny bit of insulation, and it's very
smooth inside. Bends are a problem, though, but there are ells in
various configurations.
ronc
On Fri, 11 Dec 2009 10:19:53 -0600 D C *Mac* Macdonald
<k2gkk@hotmail.com> writes:
>
> No matter what you use to try to get heat from
> one place to another in a coach, you are doomed
> to disappointment unless you can install adequate
> amounts of insulation around the duct.
>
> Also, corrugated ducting will have a great deal
> of loss of heat due to the friction of the air
> flow by the ripples of the interior surface.
>
Ron & Linda Clark
1978 Eleganza II
North Plains, ORYGUN
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Ron & Linda Clark
North Plains, ORYGUN
78 Eleganza II
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| Re: [GMCnet] Furnace Boost fan [message #67192 is a reply to message #67185] |
Fri, 11 December 2009 11:54  |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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Senior Member |
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Ron is absolutely correct when it comes to the "Equivalent Duct
Length". The problem that exist for us in that particular run is that
it has several turns and also reduces in size as it goes to the bath
at least in our coach. It looks like 2" as it runs by my water tank,
yours may be different.
There are a number of standard values for different duct components
you can use to calculate overall EDL. These I found on a ventilation
web site.
I will only give the 4" values as that is what exist in most of our
coaches.
Smooth metal duct is Actual duct length X 1
Flex Alum duct is Actual duct length X 1.25
Insulated Flex duct actual duct length X 1.5
Elbows and turns add 15 feet for each.
So as an example if we are looking at 15' of duct plus 2 turns the EDL
could be as much as almost 49 feet. That is a long way to push air
and it is not easy to get the heat there.
J.R. Wright
On Dec 11, 2009, at 12:24 PM, rallymaster wrote:
> I used black ABS pipe of the appropriate size to carry the air
> around the
> coach. Its thickness provides a tiny bit of insulation, and it's very
> smooth inside. Bends are a problem, though, but there are ells in
> various configurations.
>
> ronc
>
>>
>> No matter what you use to try to get heat from
>> one place to another in a coach, you are doomed
>> to disappointment unless you can install adequate
>> amounts of insulation around the duct.
>>
>> Also, corrugated ducting will have a great deal
>> of loss of heat due to the friction of the air
>> flow by the ripples of the interior surface.
>>
>
> Ron & Linda Clark
> 1978 Eleganza II
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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