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Active Contributor

Join Date: Aug 2011
Posts: 23
Good Answers: 1

Coil Terminology Question

08/31/2015 3:33 PM

Hi

While I deal with steam in a number of different ways, I don't have a lot of experience with coils. I let the experts size them. I gave the following information to a coil manufacturer and he used terminology that am unfamiliar with. When I asked him about it, the defined it in the same terms which didn't help at all.

Incoming air Temp: -11.84 deg F

Desired air Temp: 320 deg F

Available minimum steam pressure 87 psig min 100 psig max

Steam Temp: 518 deg F

Fan: 21030 CFM

Pressure: 26" WG

When I gave him the pressure he asked if the housing would need to be air tight as the coils they make are made with ferrules and said otherwise the coil would be "pushing air". Can someone give me some idea what he means by that?

Thanks

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Pathfinder Tags: Air coil coils pushing steam
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Commentator

Join Date: Sep 2014
Posts: 59
Good Answers: 2
#1

Re: Terminology Question

08/31/2015 5:57 PM

I'm not sure what your application is but here is a technical article from Carrier on steam coils, which includes a chapter on terminology:

http://dms.hvacpartners.com/docs/1001/Public/0A/TDP_796-052_PREVIEW.pdf

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Join Date: Aug 2014
Location: Port Macquarie N.S.W. Australia
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#2

Re: Coil Terminology Question

08/31/2015 10:52 PM

Many heating coils are constructed with ferrules on the coil piping where it passes through the fin assembly housing in order to reduce abrasion of said pipe due to relative movement between the parts.

These ferrules must be a reasonably loose fit to allow for expansion and contraction of the piping, and will allow the passage of pressurised air from the fin assembly to the outside of the coil. This could be called "pushing air" as it indeed pushes air out of the plenum, it could also draw air into the plenum dependent on the fan configuration, but either way, the integrity of the system would be compromised.

One way to prevent this is to enclose the entire coil assembly inside the plenum and just pass the feed and return pipes through the enclosure and seal them at those points.

You can clearly see the ferrules where the piping exits the housing in the picture below.

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Active Contributor

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#3
In reply to #2

Re: Coil Terminology Question

09/03/2015 4:43 PM

Spades

Ah! I picture is worth 1000 words! Thank you so much!

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