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Retrozone and Flexdamper are trademarks of Retrozone inc.

3151 Rectangular Damper 

These are CUSTOM, Made-To-Order dampers

 that take approximately 3-4 business days to make

3151 Series Mechanical Rectangular Damper, rectangular dampers, mechanical damper, custom damper, hvac, air conditioning supplies, RetroZone
3151 Series Mechanical Rectangular Damper, rectangular dampers, mechanical damper, custom damper, hvac, air conditioning supplies, RetroZone

Steps to ordering Rectangular 2 wire Dampers:

1. Size:  Choose any size above. Standard sizes shown are custom-made in 3-4 business days. All dampers are slightly undersized 1/8 inch in both dimensions to slip into an existing duct. Add foam weather stripping to outside of housing to take up any extra space and get a tight fit. A slightly undersized damper works great, but too large can be a problem.

2. Choose Motor Configuration: “Power Open / Spring Close” OR "Power Close / Spring Open": Specify what you want this spring return damper to do when power is removed, either open or close. Tip: If you are hooking this damper to a simple thermostat or switch for direct control, order  “Power Open / Spring Close”. If used in a zone control system, order “Power Close / Spring Open”. 

3. Which side do you want the motor mounted on? Standard and most common is a side (short side of the damper) mounted motor, but you can also have the motor placed on the long side, or bottom, of damper, at no extra charge.

4. Choose motor voltage: Our standard dampers are 24 volts AC, which is the standard voltage in the HVAC industry, however 110 volts AC is also available for an additional charge.

5. If you need special sizes or options, don’t hesitate to call. When in doubt, just call us at 972-633-8104 and we will answer any questions you have! Due to the large number of sizes and configurations available, these dampers are returnable only subject to a 25% restocking fee. Buyer also pays return shipping costs, these dampers are custom built to order. 

Please Check sizes and motor side carefully.

Ask questions and measure your duct carefully and ensure you order the correct size.

Each damper is made to your specification.

06x06    $150.15

08x06    $152.25

10X06   $154.35

12X06   $158.55

14X06   $160.65

16X06   $162.75

18X06   $166.95

08X08   $156.45

10X08   $160.65

12X08   $162.75

14X08   $166.95

10X10   $162.75

12X10   $173.25

12X12   $175.35

20X06  $172.20

22X06  $176.40

16X08  $176.40

18X08  $178.50

20X08  $182.70

22X08  $186.90

24X08  $189.00

14X10  $178.50

16X10  $184.80

18X10  $186.90

20X10  $191.10

14X12  $186.90

16X12  $194.25

18X12  $198.45

14X14  $194.25

16X14  $198.45

18X14  $206.85

24X06  $181.65

22X10  $196.35

24X10  $200.55

20X12  $202.65

22X12  $206.85

24X12  $213.15

20X14  $211.05

22X14  $215.25

24X14  $223.65

OEM quality damper is sold nationwide under a major HVAC manufacturer's name and is our most popular rectangular damper. Used for zone control systems or slave zones into unoccupied areas, these dampers are all 24vac driven and can be connected directly to a thermostat for simple control of any room or office. Also works with any zone control system using a 2 position, 24vac damper. Constructed of all aluminum and stainless steel parts for long corrosion free operation, these dampers are tested to the industry standard 250,000 cycles of operation, and carry a one year guarantee. All damper blades ride in nylon bushings, for rattle free operation, unlike some other brands, and are made in the USA using the industry proven Hansen “Synchron” motor, with a current industry leading low replacement cost - compare that to other brands!

  • Odd sizes available in 1 inch increments
  • 24 volts AC (110volts available, additional charge)
  • Compatible with almost all brands of zone controllers (for use with zone controllers, order as Normally Open)
  • Compatible with direct to thermostat operation (order as Normally Closed)
  • Undersized 1/8 inch in both dimensions to easily insert into duct
  • Requires a 2.5 to 3 inch slot in side of duct to install, motor faceplate is 5 inches wide
  • 15 second or less actuation time on standard motor
  • Precision aluminum blades
  • 2 wire operation on standard unit, see our other series for 3 wire, power open/power close commercial grade motor (Also see our commercial spring return series for Heavy Duty applications)
  • Standard damper rated to 1 inch pressure (great for all residential and most light commercial, consult factory for higher pressure ratings)
  • Long term integrity: A 20 year proven design with low cost replacement (Motors, springs, and other parts available at reasonable prices - not so with most other dampers)


  • Body width: 2.25 inches
  • Construction: All aluminum and stainless steel
  • Mounting plate width: 5 inches
  • Motor Height: 2 tall, 2.5 inches wide, 4.25 inches wide
  • These are top quality dampers that are being sold factory direct.
  • The only thing these dampers are missing are the several levels of price markup that is usually present on this type of damper.
  • Qualified technical assistance is a hallmark of our service, so please e-mail support@retrozone.com with any questions
  • If you are building a new home, trying to solve comfort problems, or energy problems, air control dampers can be a great solution
  • Existing duct systems, these dampers work great
  • Any of our Robert Shaw Series Backlit thermostats are certified to directly operate these dampers, as well as any of our 24 vac transformers
  • If you need multiple dampers per zone, check out our retrofit Flexdampers(tm). Zoning control and air control become feasible even when you need 10 or 20 dampers in a duct system.

Available Sizes

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