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tumble dryer vent pipe length?

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Jules

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Aug 20, 2009, 4:47:54 PM8/20/09
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One of the to-do list tasks is to throw the tumble dryer down in the
basement... does anyone know a typical limit for vent pipe length (and or
number of turns)?

Obviously "short and straight as possible" is good, but I've got a few
options as to where I'll put the vent on the outside wall above, some
better than others (flowers / bushes in the way, and whatever I do* the
pipework's going to be passing up through the kitchen floor behind the
floor-level cupboards)

* unless dryer vents exist in long-and-thin profile, rather than the usual
square? The basement ceiling sits at about 3" above ground level so
there'd be space to fit something between the beams at ceiling height (I
want to avoid a concrete trough such as around basement windows, which
would just end up collecting water and filling up with dead leaves).

ta

Jules

Tim S

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Aug 20, 2009, 4:54:10 PM8/20/09
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Jules coughed up some electrons that declared:

Could you not adapt the dryer to long and thin (aka rectangular) ducting,
eg:

http://www.tlc-direct.co.uk/Main_Index/Ventilation_Index/Ducting_Flat_5/index.html

If you can adapt the tumble dryer to 4"/100mm round then there are adaptors
for round to the above. If not, then there's duct tape :)

TLC don't have the full Manrose range - for example you can get 45 degree
bends in either axis which may be useful.

HTH

Tim

Tom

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Aug 20, 2009, 6:09:42 PM8/20/09
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"Jules" <jules.rich...@remove.this.gmail.com> wrote in message
news:pan.2009.08.20....@remove.this.gmail.com...

I'm not sure if a condensing kit would work? Might be worth a try in order
to avoid running pipe though a floor. Copy and paste this link for an idea:

http://www.toolstation.com/shop/Electrical/Ducting/Tumble+Dryer+Condensing+Kit/d190/sd3083/p65417

Some other people on here may have experience of such units.

Tom


Jules

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Aug 20, 2009, 6:10:43 PM8/20/09
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On Thu, 20 Aug 2009 21:54:10 +0100, Tim S wrote:
> Could you not adapt the dryer to long and thin (aka rectangular) ducting,

Yep! I'd not really thought of using it in a non-heating context (I was
going to find some plastic pipe for the dryer), but I don't see why the
galvansied stuff shouldn't do the job. As I'm in the US, there's *heaps*
of ducting of all sorts of configurations on the shelves at the DIY sheds
(actually I've even got a round to 12x2" rectangular section sitting in
the spares pile, although I don't remember what diameter it is now; I
think the dryer's 4")

What I'd be lacking though is a rectangular vent to go on the outside wall
- one of the plastic ones with slats which open up when there's airflow,
but which stop crap and critters getting in otherwise. I think I've only
ever seen ones for dryers (or cooker fume extraction etc.) in square
profile, not rectangular... I'll have a poke around at the local DIY
places, though.

> If not, then there's duct tape :)

:-) If it needs taking apart, use an angle grinder. If it needs putting
together, use duct tape...

cheers

Jules

Harry Bloomfield

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Aug 20, 2009, 7:34:49 PM8/20/09
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Jules submitted this idea :

> Obviously "short and straight as possible" is good, but I've got a few
> options as to where I'll put the vent on the outside wall above, some
> better than others (flowers / bushes in the way, and whatever I do* the
> pipework's going to be passing up through the kitchen floor behind the
> floor-level cupboards)

Might you not find that the moisture condenses in the pipe and simply
runs back down?

Might it not be better to try to condense it deliberately and into a
drain, rather than venting it? All you need to do is create a large
cold surface area for the moist air to pass over.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk


David

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Aug 20, 2009, 8:08:17 PM8/20/09
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On 20 Aug, 21:47, Jules <jules.richardsonn...@remove.this.gmail.com>
wrote:

IIRC the manual for my Miele dryer has a formula for calculating the
effective duct length etc, might be useful.

Jules

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Aug 20, 2009, 9:51:11 PM8/20/09
to
On Fri, 21 Aug 2009 00:34:49 +0100, Harry Bloomfield wrote:

> Jules submitted this idea :
>> Obviously "short and straight as possible" is good, but I've got a few
>> options as to where I'll put the vent on the outside wall above, some
>> better than others (flowers / bushes in the way, and whatever I do* the
>> pipework's going to be passing up through the kitchen floor behind the
>> floor-level cupboards)
>
> Might you not find that the moisture condenses in the pipe and simply
> runs back down?

Hmm, now that's a really good point. Maybe I'll see if I can find a good
US equivalent to uk.d-i-y as lots of folk here have dryers in the
basement, so there must be a common way of handling it (may be that
everyone uses a condenser as Tom mentions!)

> Might it not be better to try to condense it deliberately and into a
> drain, rather than venting it? All you need to do is create a large cold
> surface area for the moist air to pass over.

Quite possibly; if I get the washing machine down into the basement (as
mentioned in another thread) the I can use the same holding tank that the
washing machine drains into to receive any liquid from the dryer.

cheers

Jules

Tim Downie

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Aug 21, 2009, 2:50:40 AM8/21/09
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"Jules" <jules.rich...@remove.this.gmail.com> wrote in message
news:pan.2009.08.21....@remove.this.gmail.com...

> On Fri, 21 Aug 2009 00:34:49 +0100, Harry Bloomfield wrote:
>
>> Jules submitted this idea :
>>> Obviously "short and straight as possible" is good, but I've got a few
>>> options as to where I'll put the vent on the outside wall above, some
>>> better than others (flowers / bushes in the way, and whatever I do* the
>>> pipework's going to be passing up through the kitchen floor behind the
>>> floor-level cupboards)
>>
>> Might you not find that the moisture condenses in the pipe and simply
>> runs back down?
>
> Hmm, now that's a really good point.

I can confirm that an extended hose on a drier becomes a very effective
condenser. When we had to locate our dryer temporarily in our garage, I had
a double length of hose on it and it worked fine for a while but then
appeared to be blocked. On closer inspection a hanging loop was completely
full of water.

I guess this could be reduced by insulating your duct or perhaps you could
think about deliberatly introducing a "U" tube type hanging loop with a
drain to capture the condensate and prevent it flowing back to the dryer?

TIm


Lobster

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Aug 21, 2009, 2:56:46 AM8/21/09
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Jules wrote:
> On Thu, 20 Aug 2009 21:54:10 +0100, Tim S wrote:
>> Could you not adapt the dryer to long and thin (aka rectangular) ducting,
>
> Yep! I'd not really thought of using it in a non-heating context (I was
> going to find some plastic pipe for the dryer), but I don't see why the
> galvansied stuff shouldn't do the job. As I'm in the US, there's *heaps*
> of ducting of all sorts of configurations on the shelves at the DIY sheds
> (actually I've even got a round to 12x2" rectangular section sitting in
> the spares pile, although I don't remember what diameter it is now; I
> think the dryer's 4")
>
> What I'd be lacking though is a rectangular vent to go on the outside wall
> - one of the plastic ones with slats which open up when there's airflow,
> but which stop crap and critters getting in otherwise. I think I've only
> ever seen ones for dryers (or cooker fume extraction etc.) in square
> profile, not rectangular... I'll have a poke around at the local DIY
> places, though.
>

Unless I'm misunderstanding the situation, why does it have to be
rectangular where it goes through the wall?

My tumble drier sits in a corner and has 5" rectangular ducting which
conducts vapour from the base of the machine to a hole in the side wall,
which requires IIRC four 90-degree bends and about 5' total length
wrapped around the machine - works fine. The hole in the wall is round,
and the ducting connects to it with something like this:

http://www.screwfix.com/prods/96549/Heating-Cooling/Ducting/Manrose-Elbow-90-Bend-100mm

Even if you want to go through the wall with rectangular ducting (which
may be advantageous), there's nothing to stop you covering the hole on
the outside wall with a square vent, anyway.

David

David WE Roberts

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Aug 21, 2009, 6:16:55 AM8/21/09
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"Jules" <jules.rich...@remove.this.gmail.com> wrote in message
news:pan.2009.08.20....@remove.this.gmail.com...

> On Thu, 20 Aug 2009 21:54:10 +0100, Tim S wrote:
>> Could you not adapt the dryer to long and thin (aka rectangular) ducting,
<snip>

> What I'd be lacking though is a rectangular vent to go on the outside wall
> - one of the plastic ones with slats which open up when there's airflow,
> but which stop crap and critters getting in otherwise. I think I've only
> ever seen ones for dryers (or cooker fume extraction etc.) in square
> profile, not rectangular... I'll have a poke around at the local DIY
> places, though.

The vents I have seen with flaps have needed a reasonable breeze to overcome
the spring and make the flap open.

Will you get enough pressure over a long run to make the flaps open?

[Ignoring, of course, the condensation issues raised elsewhere.]

Jules

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Aug 21, 2009, 8:34:12 AM8/21/09
to
On Fri, 21 Aug 2009 11:16:55 +0100, David WE Roberts wrote:
> The vents I have seen with flaps have needed a reasonable breeze to overcome
> the spring and make the flap open.
>
> Will you get enough pressure over a long run to make the flaps open?

Yes, that was partly my original question, I suppose - not only must there
be some maximum length / number of turns beyond which the dryer becomes
useless, but it does need a reasonable flow just to get the louvers on
the vent cover to open.


Jules

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Aug 21, 2009, 8:54:28 AM8/21/09
to
On Fri, 21 Aug 2009 07:56:46 +0100, Lobster wrote:

> Jules wrote:
>> On Thu, 20 Aug 2009 21:54:10 +0100, Tim S wrote:
>>> Could you not adapt the dryer to long and thin (aka rectangular) ducting,
>>
>> Yep! I'd not really thought of using it in a non-heating context (I was
>> going to find some plastic pipe for the dryer), but I don't see why the
>> galvansied stuff shouldn't do the job. As I'm in the US, there's *heaps*
>> of ducting of all sorts of configurations on the shelves at the DIY sheds
>> (actually I've even got a round to 12x2" rectangular section sitting in
>> the spares pile, although I don't remember what diameter it is now; I
>> think the dryer's 4")
>>
>> What I'd be lacking though is a rectangular vent to go on the outside wall
>> - one of the plastic ones with slats which open up when there's airflow,
>> but which stop crap and critters getting in otherwise. I think I've only
>> ever seen ones for dryers (or cooker fume extraction etc.) in square
>> profile, not rectangular... I'll have a poke around at the local DIY
>> places, though.
>>
>
> Unless I'm misunderstanding the situation, why does it have to be
> rectangular where it goes through the wall?

Well the underside of the ground floor (i.e. the floorboards, which also
form the ceiling of the basement below) sit above ground level by only
about 3", so if I drill right at ceiling height in the basement through to
the outside, I'll only have about 3" of vertical space - but the
joists in the basement (supporting the floor above) are on 16" spacing, so
there's quite a bit of horizontal space between them to
accomodate a wide vent.

(It's actually more like 4" of height I've got to work with, but I don't
want the exterior vent sitting flush against the grass, and the
standard square vents seem to be 4" x 4")

> My tumble drier sits in a corner and has 5" rectangular ducting which
> conducts vapour from the base of the machine to a hole in the side wall,
> which requires IIRC four 90-degree bends and about 5' total length
> wrapped around the machine - works fine.

That's useful. I think to get it through the wall at ceiling height in the
basement I'm looking at two 90-degree bends, a vertical run of about 7'
and horizontal of 4'.

To just run it up via the kitchen (hidden by cupboards) would be maybe
8' and again two 90-degree bends - which is shorter, but running it via
another room does feel like a bodge, even if nobody would ever see it!

Unfortunately I can't get the dryer closer to where I'd want to vent it
via the top of the basement wall, as the well pump and pressure tank are
in the way - and relocating those is asking for trouble :-)

I could raise the dryer up so it's not at floor level in the basement, I
suppose - after all, it's less convenient that way anyway. But I'm not
sure if saving 3' (or so) on the vertical would be 'enough' to go out via
the basement wall (although it sounds like it could be for the bodgey
kitchen route).

> Even if you want to go through the wall with rectangular ducting (which
> may be advantageous), there's nothing to stop you covering the hole on
> the outside wall with a square vent, anyway.

It's just a clearance issue on the outside - and I think anything other
than having the vent cover flush with the outside wall would just look
messy.

My experience of 'pits' on the outside for things like basement windows is
that they tend to fill up with debris and make for great moisture traps,
so I'm reluctant to go that route if I can help it.

Maybe I need to source some suitable pipe and just do some tests (although
that would best be done when outside air is coldest, I suppose, but then I
don't think the basement gets much lower than about 45F in Winter - so if
I pick a cold night in the coming weeks...)

cheers

Jules

S Viemeister

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Aug 21, 2009, 9:36:08 AM8/21/09
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Jules wrote:
>
> Well the underside of the ground floor (i.e. the floorboards, which also
> form the ceiling of the basement below) sit above ground level by only
> about 3", so if I drill right at ceiling height in the basement through to
> the outside, I'll only have about 3" of vertical space - but the
> joists in the basement (supporting the floor above) are on 16" spacing, so
> there's quite a bit of horizontal space between them to
> accomodate a wide vent.
>
> (It's actually more like 4" of height I've got to work with, but I don't
> want the exterior vent sitting flush against the grass, and the
> standard square vents seem to be 4" x 4")
>
>
Have a look here - they sell all sorts of ducting and transitions from
rectangular to round, in a number of sizes. The 3-1/4" x 10" size might
do you.

> I could raise the dryer up so it's not at floor level in the basement, I
> suppose - after all, it's less convenient that way anyway. But I'm not
> sure if saving 3' (or so) on the vertical would be 'enough' to go out via
> the basement wall (although it sounds like it could be for the bodgey
> kitchen route).
>

When we installed a dryer in our basement, it was placed on a platform
for two reasons - one, to keep it away from possible flooding, and two,
to make it easier to load and unload. If you install a big drawer in
the platform, it can keep laundry supplies neatly contained.

Jules

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Aug 21, 2009, 10:02:55 AM8/21/09
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On Fri, 21 Aug 2009 09:36:08 -0400, S Viemeister wrote:
> If you install a big drawer in
> the platform, it can keep laundry supplies neatly contained.

That's an excellent idea. There was me pondering on what the heck to use
the 'wasted space' for if I did go that route. :-)

J.

Jules

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Aug 21, 2009, 11:45:39 AM8/21/09
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On Fri, 21 Aug 2009 07:54:28 -0500, Jules wrote:
> To just run it up via the kitchen (hidden by cupboards) would be maybe
> 8' and again two 90-degree bends - which is shorter, but running it via
> another room does feel like a bodge, even if nobody would ever see it!

OK, just been doing some measuring, and I think I have a solution...

As the basement walls are around 8" thick, I think I can cut through at a
45 degree angle rather than horizontal, which gains me quite a bit of
height where the vent pipe will exit through the outside wall.

Doing it that way should allow the vent to sit high enough up above ground
outside, still allow me to use a square vent, and allow me to vent out via
the wall directly behind the dryer in the basement space, rather than a
longer run to a different wall or up through the kitchen.

Total run will probably still be about 5' with the dryer on a platform,
but that seems short enough that I'm willing to chance it (it has no
problems with the current 3" run via flex-duct, anyway). The only issue is
whether the exhaust from the dryer is going to cause problems in hitting
the vent at 45 degrees rather than head-on, so I'll rig up some sort of
test there with the existing vent cover and see...

cheers

Jules

gunsmith

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Aug 21, 2009, 2:36:06 PM8/21/09
to

You can get the same effect if you use a stacking kit to put the dryer
atop the washer, assuming the appliances are stackable.

Jules

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Aug 21, 2009, 7:01:15 PM8/21/09
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On Fri, 21 Aug 2009 11:36:06 -0700, gunsmith wrote:
> You can get the same effect if you use a stacking kit to put the dryer
> atop the washer, assuming the appliances are stackable.

It's all top-loaders this side of the Pond, unfortunately. USians are
just discovering front-loaders, but sales volumes are still low, so as a
consequence they come with a quite alarming price-tag :-)


KPLLOYD

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Jul 18, 2015, 12:44:04 PM7/18/15
to
replying to Jules, KPLLOYD wrote:
> jules.richardsonnews wrote:
>
> That's an excellent idea. There was me pondering on what the heck to use
> the 'wasted space' for if I did go that route. :-)
> J.

The Platform/deck out of pressure treated materials is a excellent way to
protect your basement utilities Water heaters / pressure tanks/ well
pumps/ Etc. Put your boiler on platform then place termite blocks on it
, Your platform idea is great insurance for each home appliance in damp
basements KP

--


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