ThisIssue

A Periodic Newsletter for Design ProfessionalsAbout Innovative Products and Ideas Worthy of Specification Consideration

April2000(E2)

You receive a call from a building owner - his just completedbuilding has objectionable diffuser noise. After much trial anderror, your jobsite investigation determines the problem is notthe diffusers, but the volume dampers that are installed in thediffusers. They are rattling and hissing.

It appears the simple solution is to remove the noisy diffuserdampers and install new round volume dampers upstream of theflex drop. But you quickly realize this solution creates aproblem of an entirely different sort – you’ll need access doorsfor all the dampers above hard ceilings – something neither theowner or the architect desires. What do you do…?

Bowden Cable Control Systems to the rescue!

Yes, Bowden Cable Control is the simple and easy solution toboth of these problems. Manufactured by Young Regulator – acompany who has been providing unique solutions for difficultHVAC applications since 1930 – Bowden Controls not onlyallow the volume damper to be installed upstream of the diffuserwhere noise and turbulence has time to dissipate, but they alsoeliminate the need for unsightly ceiling access doorsor expensive fire rated access panels.

In addition to solving damper control and access above hardceilings, Bowden Controls are also perfect for dampers which are:

• above a HEPA filter ceiling• above special architectural ceilings• in secure prison cells• in underground ductwork• in high atriums or vaulted ceilings• in all noise sensitive applications

What features put Bowden ahead of the competition? OnlyBowden uses a unique rack and pinion gear drive that producesa smooth push/pull drive motion to actuate the volume damper.Only Bowden allows the damper to be located up to 30 feet fromthe controller in typical installations and up to 50 feet away instraight cable runs.

In contrast, other brands of cable operators use a worm geardesign that actuates the damper with a twisting or rotating cableaction. These designs are not only prone to binding andcatching, they are also restricted to relatively short runs ofstraight cable.

If you want a system that saves the building owner money,satisfies the aesthetic concerns of the architect and is fast andsimple to install, read on to see how the Bowden System is theno-hassle cable system to specify!

Practical Solutions To Everyday Problems!

Rack and Pinion Cable Operator # 270-275

Young Regulator #5020-CCDamper with Bowden damper control assembly

OVERVIEW

Bowden Cable Control Systems

What Do Contractors Say about Bowden?

BENEFITS TO THE ENGINEER

Quiet – Bowden systems allow the noise generatingdamper to be installed in the duct away from the ceilingoutlet, greatly reducing room noise.

Adaptable – Available with five control mounting options,Bowden controls work equally well with retrofits andexisting dampers for design flexibility.

Versatile – Bowden cable controls are available for roundor rectangular dampers, as well as in kit form to fit othermanufacturers’ dampers. They also give technicians theability to control dampers in difficult to reach areas, suchas dampers encased in concrete.

Inconspicuous – The ceiling regulator can be mountedanywhere you want it, up to 50 straight feet from thedamper. Unlike worm or miter gear systems, the Bowdencontrols are not required to be mounted directly below thedamper.

Locking Controller – The rack and pinion controllersecurely holds the damper in position for precisedependable settings.

Efficiency – When the damper is remote from the diffuser,the air turbulence it generates has time to dissipate,allowing the diffuser to perform optimally.BENEFITS TO THE OWNER/CONTRACTOR

Quick Installation – The Bowden cable system is quickand easy to install. Its uncomplicated design substantiallyreduces installation costs.

Noise Reduction – Bowden allows dampers to beinstalled up to 30 feet from the diffuser (50 feet is possiblewith no turns). This greatly reduces noise from thedamper traveling to the diffuser.

Simplicity – No complicated linkage from damper toceiling regulator. The flexible cable and wire can berouted around electrical conduit, piping and otherobstructions, without fear of binding or catching.

Centrally Locatable – Bowden allows for routingmultiple damper controls to one location for convenientcentralized balancing.

Easy Balancing – Bowden Control’s unique designmeans balancing time is reduced by two thirds. Thistranslates to significant savings for the owner.

No Access Doors – Bowden cable systems eliminate theneed to require unsightly access door panels in theceiling. The inconspicuous controls can be hidden inremote locations or even in concealed linear diffuserplenums.

Bowden Cable Control

“The Best Way to Remotely Control a Balancing Damper”.

#830A-CC Rectangular Damper

SPECIFICATION TIP!Contractors often miss Bowden specifications at bid time.To make sure you get what you specify without a fightdown the road, give any air distribution device that requiresBowden Controls a separate tag number on your equipmentschedule. Note in the remarks column for these tags:“Bowden remote cable control and damper required.”

✎#270-301 Bowden control kit #270-896C Bowden control kit

“We installed the Bowden Cable System in a casino and werevery impressed with the aesthetics and ease of installation. Ittook less than a quarter of the time to install compared toworm/miter gear systems.”

Mike Osburn, Site Foreman, University Mechanical

“Bowden Cable Control systems can be balanced in half thetime of manual volume dampers and with only one personinstead of two. Bowden can pay for itself on the first balancing!”

James Rosier, Vice President, Equal Air Balance,N.E.B.B. member

Control Mounting Options

3” Dia. Cap

3/8”3

3/8”3

1/4”2Steel Pipe

7/8” Dia. CapCeiling

Plastic Cap

Pipe Support

Support Bracket

“U” Bracket

Another perSPECtive...

By Dave McIntyre

The question, “How do you set andbalance airflow through a diffuser in ahard ceiling?” is most often answered,“with an opposed blade damper in thediffuser neck”. However, for manynoise sensitive applications, that answercould lead to unexpected job siteproblems.

It’s little known fact of diffuserperformance ratings that all noise levelspublished are based on devices testedwithout dampers or other restrictiveaccessories. It’s only in the footnotes orengineering guidelines of a catalogwhere you learn that dampers aresignificant noise generators, commonlyadding anywhere from 5 to 15 NC perdiffuser outlet. With acousticallysensitive hard ceiling applications,multiple dampered diffusers can resultin room noise levels as much as 20 NChigher than predicted from catalogeddiffuser ratings. If not anticipated,this can be a most unpleasant fielddiscovery.

If you’ve experienced this problem, thenyou may have already adjusted yourspecifications to preclude the use of anydampering device at an air outlet. Thecommon alternative is to specifymanual balancing dampers eight feet ormore upstream of the diffusers. Thisworks fine in lay-in ceilings, but forhard ceilings, the only way to accessthese balancing dampers is throughmultiple access doors or ceiling panels.The catch is: These access doors arerarely acceptable to the architect orbuilding owner.

When your project needs volumedampers above inaccessible ceilings, thebest “answer” is to specify effective andinexpensive Bowden Cable Controlsby Young Regulator - the simplesolution to damper noise and accessproblems!

SPECulations is published by: Toro-Aire, 1708 Mahalo Place, Dominguez Hills, CA 90220 • Phone (310) 632-6000 • Fax: (310) 632-8919

Email: publisher@toroaire.com Web Page: www.toroaire.com

Do you have a customer or colleague who would enjoy SPECulations? Send us their name and address and we will add them to our mailing list.

Editor-In-ChiefDave McIntyre

Managing EditorMonica Froeber

Technical EditorVictor Petring

Web ConsultantKarin West

Copy ChiefMichael Green

Another Solution From Young Regulator...Opposed Blade Volume Dampers For Smaller Ducts

Reduce Noise and Turbulence

Because opposed blade dampers distributeair more evenly, reducing both turbulenceand noise, their advantages over parallel orsingle blade dampers are well recognized.For these reasons, most designers insist onopposed blade dampers for their HVAC ductdesigns.

However, in smaller ducts, unless youspecify otherwise, a single blade balancingor volume damper is almost always installed.When a single blade damper is 100% open,it typically is not a problem. The problemsarise as you begin to close the damper bladeto reduce air volume. As the single bladecloses, the surface area is increasedsignificantly against the airflow. This causesthe airflow to be much more turbulent,adding pressure drop and undesired systemeffect.

In addition, when the air passes through thenarrow opening between the damper bladeand the duct, high frequency noise isgenerated. A significant amount of radiatednoise is also produced by the jet of air froma single blade damper against the flatdrum-like bottom surface of the duct.

Solution: Young Regulator series 820(manual) or 830 (Bowden controlled)opposed blade volume dampers specificallydesigned for small ducts. These costeffective dampers feature strong extrudedaluminum blades on 2" centers withindividual Teflon bushings on every bladefor dependable, rattle-free operation.Available with horizontal or vertical blades,these high free area dampers provide smoothand accurate volume control in duct sizes assmall as 2" in height!

Young Regulator’s opposed blade dampers (above allow air to be evenly distributed over theblades while reducing turbulence and noise. A single blade damper (below) reduces aircontrol while increasing turbulence and air stream noise.

Manual Rectangular Damper #820A-L

Standard single blade damper

EVEN AIR FLOWQUIET

EVEN AIR FLOWQUIET