CLA Connect Open Forum

Subject: Single pocket dryers venting?

1.  Single pocket dryers venting?

Posted 10 days ago
Hi everyone,
 what is the best way to vent single pocket dryers ?
1. Just Straight out to the wall ​(1 feet above floor)
2. Come up with an elbow than another elbow out to the wall (7 foot above floor)
thank you.

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Linh Nguyen
Store Owner/ Employee
Mobile AL
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2.  RE: Single pocket dryers venting?

Posted 9 days ago
​Linh

Vent the dryers out at the 7 ft height. I once bought a laundromat that had the dryers vented out just above the floor. I got a day's worth of exercise just working on one dryer stepping over 8 vents to get to it.

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Larry Adamski
Muskegon Laundromat
Spring Lake MI
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3.  RE: Single pocket dryers venting?

Posted 9 days ago
What is important that you provide make up air behind the dryer . One square foot for every dryer pocket .

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Larry & Gail Vladimir
Store Owner/ Employee
Bakers Centre Laundry
Levittown PA
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4.  RE: Single pocket dryers venting?

Posted 9 days ago
Linh,

The problem of course is the eventual accumulation of lint.

If you vent straight out, it's the easiest & most efficient path for airflow. You may never get an accumulation anywhere in that ductwork, but like Larry A said, do you really want to step over ductwork every time you go back there?

If you vent up and out, you will eventually get an accumulation at the elbow that is located at the bottom of the ductwork. This is because every time the dryer stops, any lint that is in the duct, will settle down to that elbow. Yes, most of the time the next start will blow it out, but eventually, you will have to open the elbows and clean them.

I have some single pockets, individually vented, that vent straight UP and out the roof, ending with a candy cane (or gooseneck) on the roof.
The ductwork itself never gets clogged, but every 2 years or so, I have to open the ductwork at the the top of the dryer where it exits, and clean the backdraft dampers.

I also agree with Larry V....makeup air is very important. Seems like you can never have too much makeup air.
Something that I have discovered from experience....If you are in a building that has restaurants, you need even MORE makeup air than the manufacturer recommends because the restaurants have powerful exhaust ducts in their kitchens that create a negative airflow in the entire building.
You also have the burden of their Grease going into the main sewer, which increases the need to snake the sewer lines more often.

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Paulie B
Store Owner/ Employee
Mr Machine
New York City NY
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5.  RE: Single pocket dryers venting?

Posted 9 days ago
If you have ample room behind the dryers, an up and out might provide better access for maintenance.  If you don't have much room behind the dryers, then a straight out system might be better.  You can build a metal  walkway above with removable panels, or a half walk if it provides enough room, if it's worth the time and money.  One foot to the top seems manageable as a step over if you don't have a lot of work to do back there.

We have restaurants with commercial hoods, and they require a make up air system...getting the balance right is tricky, so we make sure they keep their doors to common areas closed during business hours.

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Les Monthei
Potential Investor
Redding CA
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6.  RE: Single pocket dryers venting?

Posted 5 days ago
I wish everybody give me the same advice, Les's idea with a walk way is also attractive to me ,but I may go with Larry's suggestion .
Paulie this  picture is vent through the roof with a clean out at my other store and I may add this clean out to this venting system .
thank you
5gnyfhLAQFGfybxckQuG_IMG_1877.JPG

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Linh Nguyen
Store Owner/ Employee
Mobile AL
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7.  RE: Single pocket dryers venting?

Posted 5 days ago
Linh,

That cleanout is a great idea! I like that a lot!
A great, simple idea that solves the problem of clean outs, making future clean outs so easy.

How is the plug attached? With a big hose clamp? I can't tell from the photo.

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Paulie B
Store Owner/ Employee
Mr Machine
New York City NY
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8.  RE: Single pocket dryers venting?

Posted 5 days ago
That interesting clean out outlet, I just saw the other day ago, on the store we take over this month.
The clean out is on each dryer, at the bottom pocket, there is the T go down (not side way) to the floor, then the wing nut removable cap, they clean every 6 months, 28 of them is a lot to do. the owner say there is a lot of lints take out every 6 months, when I look on the roof, there is very clean roof, even it next to the AC, the coil show no sign of lint.
I forget to take picture, but the duct system make very efficient with heat exchange unit to heat up the intake air.

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Phu Tran
Store Owner/ Employee
Garland TX
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9.  RE: Single pocket dryers venting?

Posted 5 days ago
Phu,

My only concern about that lint clean out would be that the smooth flow of air up the duct may become turbulent at the clean out tee and actually cause increased lint accumulation within the duct.  Obviously, I don't know this is happening - it's just a thought I had.  I have never seen lint clean outs built into individual exhaust ducts in this way.

The heat exchanger sounds interesting.  Could you post a picture?

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Larry Adamski
Muskegon Laundromat
Spring Lake MI
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10.  RE: Single pocket dryers venting?

Posted 5 days ago
Phu,

You bring up an interesting point of preheating the makeup air.
I'm now wondering if it's practical to clamp some kind of "heat sink" radiating fins on the outside of the ductwork.
Totally passive, that would transfer heat from the ductwork to the ambient air.

I seem to remember that was a company years ago that made a collar of a spiral of copper water pipes that would be installed over your ductwork to preheat the incoming water for your boiler.

Something like this might work....This image is using hot wastewater, but it could easily be converted to ductwork, imho...
Not sure about the possibility that the cold water spiral may chill the inside of the ductwork to the point that sweating would cause lint buildup. Can anyone confirm?

wEaMr1GhSfOfrE8aSesY_heat-recovery4.jpg

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Paulie B
Store Owner/ Employee
Mr Machine
New York City NY
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11.  RE: Single pocket dryers venting?

Posted 5 days ago
Paulie,

Yes, I do think internal condensation could be a real concern but I'd also worry about those coils freezing and bursting in the winter time.

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Larry Adamski
Muskegon Laundromat
Spring Lake MI
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12.  RE: Single pocket dryers venting?

Posted 5 days ago
For those who need to help heat a room adjacent to their bank of dryers ... something to consider possibly:

On 8 of our single pocket dryers we had to find a way to make room for the upper part of our dog wash addition.  So we had the sheet metal contractor do a common duct work.  While were were at it we designed an insulated outer chamber where it does heat up an in between continuous normally dead air area.  Two vents open up to the dog wash & a fan pushes the warmed air into the dog wash.  The dog wash's programmable logic controller controls the on & off of the fan when conditions allow it to do some good.  No worry about a potential frozen pipes' - preheating domestic water setup.   However it does blow little cost no problem creating "warm air" from the surface heat on its way  to two large enough dog ear style exhaust vents.  It seems like some worthwhile data gathering to verify the amount of gain of btus is in order ... to potentially help the public good in our northern colder climates.   The PLC actually already does some of the logging automatically ...

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Michael Walsh www.kingkoin.com
Store Owner/ Employee
King Koin Laundry, Car n Dog Wash
Bismarck ND
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13.  RE: Single pocket dryers venting?

Posted 5 days ago
I had a mat years ago where I zigzagged a 1-1:2" copper pipe resting right on top of a bank of dryers. It preheated the boiler water quite nicely.
Not sure if it was legal though. Probably not, but then again, I took a lot of chances back then.

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Paulie B
Store Owner/ Employee
Mr Machine
New York City NY
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14.  RE: Single pocket dryers venting?

Posted 5 days ago
I expect we could install a low volume exhaust fan / duct of sorts set up high behind the dryers where it is usually pretty warm and duct the air to the L Mat space thru a basic filter.  We have dryer banks at both ends of the L Mat.

Maybe we could then duct the hot air flow out of the building up high behind the dryers in the summer months.

Anyone try this ?

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Les Monthei
Potential Investor
Redding CA
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15.  RE: Single pocket dryers venting?

Posted 4 days ago
Les,

Why would you want to exhaust warm air out from behind the dryers? Wouldn't drawing that warm air in, allow the dryers to work easier? It's basically free preheated air for them. Less need for the gas to kick on.

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Paulie B
Store Owner/ Employee
Mr Machine
New York City NY
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16.  RE: Single pocket dryers venting?

Posted 5 days ago
Paulie
The heat exchange is air to air, there is a huge duct box 10x10x6, which stick out from the roof take in the fresh air, the first group 14 dryers duct will go through the box, the fresh air will exchange the temp with the exhaust duct, then move down by the 2x10 duct extend all the way close to the floor.
There are also 2 opening 30x30 electric shuttle to the roof, control by static pressure sensor, auto open when the pressure inside different than the outside. Seem very expensive and well design.
Les you idea may work well, however it need the air return back to the back room dryer to equal the static build up inside the store and lower at the dryer back room, so it not need to pull more cold fresh air in to equal the static pressure. The ratio need to be 1:1

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Phu Tran
Store Owner/ Employee
Garland TX
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17.  RE: Single pocket dryers venting?

Posted 4 days ago
A couple of thoughts on Paulie, Phu, & Les's warm air proposition.  Supposedly cold air contains way less moisture than warm air so pre-heated air may not be the deciding factor.

When it comes to Phu's make up air based on static pressure ... the ideal would be for a Belimo actuator(s) that would accurately control the opening for make up air based on the negative air pressure need.  A bit more sophisticated on the control end but possibly worthwhile for some of us.   One thing to watch out for is where the weather goes below 20° F you might start having mechanical freeze ups with the levers' ever proportional opening process.

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Michael Walsh www.kingkoin.com
Store Owner/ Employee
King Koin Laundry, Car n Dog Wash
Bismarck ND
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18.  RE: Single pocket dryers venting?

Posted 4 days ago
From what I know about ducting dryers, you need 1.4 cu. ft. of makeup air per single pocket (30 35) more for larger. I agree with Larry on the clean out disturbing the air flow. The runs need to be as straight as possible, using gradual bends, either into a common header or preferably straight out  the wall.

A couple years ago, I replaced an entire row of dryers that required moving to larger diameter ducting. Particular attention was paid to making the straightest runs possible into the header. It worked so well that I actually had to lower the dryer default factory temp. settings. They all ran too hot, so that proved to me that properly ducting dryers really matters.

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Thomas Bright
Owner
Bright's Coin Wash
Marengo Illinois
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19.  RE: Single pocket dryers venting?

Posted 4 days ago
The clean out do have a cap and that cap just snug inside the clean out ,to remove the cap use a flat head srew driver or a car key to pry it out . No clamp involved and of course no air leak ,its very tight fit .

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Linh Nguyen
Store Owner/ Employee
Mobile AL
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