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  • Standard motor Belimo LMB24 with 95 second run time, 24volts ac or dc. 2.0 va 1.5 watts powerful 45 in lbs of torque, UL and other ratings
  • 5 year factory warranty
  • Frame width 2 and 1/8 inch wide, mounting faceplate 5 inches
  • Dampers are slightly undersized to fit in duct
  • Mounting end plate is 5 inches wide 1/2 drive shaft works with hundreds of motors
  • Standard Damper Sizes (in even inch increments, Odd sizes ok, consult factory) [Note: all sizes over 24 inches come with bottom “long side” motor mount unless short side mount is requested which is “Jackshafting”. An additional fee and time is added for Jackshafting*.]
  • Available Standard Sizes, odd sizes available

Rectangular Damper Questions You need to answer

 to COMPLETE Your Order:

A. Size, like; “8 inches x 24 inches”

B. What side the motor is on using the selected measurements; like “8 inch side”

C. Normally Open or Normally Closed when unpowered:

This means with no power applied, is the damper open?

or closed? Important: When used with a zone control system, you will need to order normally open. When used tied directly to a thermostat or switch, you will want to order normally closed.

D. Rectangular dampers are custom made and not returnable due to size or configuration errors.

Please carefully review your confirming invoice to ensure correct product for your application.

SD “Super Duty” 3085 Series
Motorized Rectangular Power Open-Power Closed 24vac Damper for Zone Control or HVAC AirControl Applications, With Belimo LMB24 commercial 3 wire damper motor

Please see our Surplus Dampers that are in stock.

3085 Series Commercial Mechanical Rectangular Damper, rectangular dampers, mechanical damper, custom damper, hvac, air conditioning supplies, RetroZone

These are CUSTOM, Made-To-Order dampers

 that take approximately 3-4 business days to make

When selecting the motor on the short side of any damper over 24” it is considered Jackshafting.

*Jackshafting requires bolting two dampers together and adding a longer shaft to control all the parts together.

Current cost for Jackshafting is $34.00****Additional Time for production as well

 Small Dampers

  8x6   $198.45

10x6   $198.45

12x6   $198.45

14x6   $198.45

  8x8   $198.45

10x8   $198.45

12x8   $198.45

14x8   $200.55

10x10 $202.65

12x10 $202.65

14x10 $206.85

12x12 $211.05

14x12 $211.05

Medium Dampers

16x6   $205.80

18x6   $210.00

20x6   $212.10

22x6   $224.70

24x6   $228.90

16x8   $205.80

18x8   $210.00

20x8   $212.10

22x8   $224.70

24x8   $228.90

16x10 $210.00

18x10 $216.30

20x10 $228.90

22x10 $231.00

16x12 $216.30

18x12 $218.40

20x12 $231.00

14x14 $216.30

16x14 $218.40

18x14 $222.60

Large Dampers

26x6   $234.15 

28x6   $236.25 

30x6   $240.45  

32x6   $242.55 

34x6   $244.65 

36x6   $246.75

26x8   $234.15

28x8   $236.25

30x8   $240.45

32x8   $242.55

34x8   $244.65

36x8   $246.75

24x10 $236.25

26x10 $240.45

28x10 $242.55

30x10 $244.65

32x10 $246.75

34x10 $250.95

36x10 $253.05

22x12 $240.45

24x12 $242.55

26x12 $246.75

28x12 $248.85

30x12 $250.95

Large Dampers

32x12 $253.05

34x12 $259.35

36x12 $261.45 

20x14 $240.45 

22x14 $244.65 

24x14 $248.85  

26x14 $253.05  

28x14 $253.05  

30x14 $259.35  

32x14 $261.45  

34x14 $265.65  

36x14 $267.75  

16x16 $232.05

18x16 $234.15

20x16 $246.75

22x16 $248.85

24x16 $253.05

18x18 $236.25

20x18 $250.95

22x18 $253.05  

24x18 $263.55

20x20 $265.65  

22x20 $265.65

24x20 $267.75

22x22 $267.75

24x22 $269.85

24x24 $271.95

The 3085 Series Commercial Damper uses the same quality, multi-opposed blade aluminum housing as the 3150 Series, but features a Belimo 24vac LMB motor, Power Open / Power Close actuator with a 90 second design actuation time. Quality American built, all aluminum and stainless steel damper with a 20 year proven history, with commercial 1/2 inch drive shaft. Rattle-free nylon bushings and multiple opposed blade design makes this the “quiet” choice.  Available Motor Options (see motor listing for more information on these motors).

Please call in your order on any of the below options; subject to change without notice.

  • Standard motor is a Belimo LMB 95 sec motor, no extra cost.
  • SF Series Belimo Spring return motors, additional cost.
  • Carrier Infinity and Trane Varitrac compatible motor additional cost.
  • Belimo Motor 15 second timing additional cost.
  • Belimo LMB-SR 0 to 10volt Modulated additional cost. May be used as a replacement damper on most zone control panels, including
  • panels that support only two wire spring return dampers. Consult factory.
  • Standard 1/2 inch commercial drive shaft accepts many different motors
  • 5 year warranty
  • Controls up to 2 inches static pressure
  • Narrow frame makes it a perfect choice for tight fits or damper replacements
  • Works with most zone control panels
  • Can be controlled directly for a thermostat with no relay needed, see slave zone diagram in technical resources (red menu button at Top/Left side of this page)
  • Available in odd sizes, one inch increments. like 9x15
  • Add on end switch available for verification or control

Our 3085 Series Rectangular damper uses the powerful and industry proven Belimo LMB commercial grade actuator to both power itself open and closed. Yet the 24vac motor uses only a stingy 2.2 watts of power since the precision gear train motor multiplies the torque for plenty of power, giving our 3085 series damper the ability to control up to two inches of static pressure for any residential and most commercial applications. These dampers have been in production for twenty years, and are sold nationally under a major OEM label. The 3085 Series Rectangular Damper is sold directly to you without the chain of markups common in the HVAC industry. This damper uses the same quality aircraft grade aluminum and nylon bushing construction as our more economical 3150 series of spring return rectangular dampers, but uses the Belimo LMB24 commercial motor mounted on an industry standard 1/2 inch drive shaft, for outstanding long term, trouble free performance. 

  • Industry standard 1/2 drive shaft damper to motor connection-Literally hundreds of different motors from different vendors will easily install on this damper, allowing easy upgrades or replacements in the future. You are not stuck with a “single sourced” motor.
  • Stops in any position when power is removed-great for air balancing operations, use with our SPDT center off switch.
  • Infinitely adjustable open and close positions-screw adjustments allow you to set maximum and minimum open and close blade position adjustments-great for fine tuning
  • and allowing some bypass air for pressure control.
  • For control by a standard thermostat with no interposing relay needed.
  • Uses only 2.2 watts or less power, far less than spring return motors, runs cooler, and far more powerful in both directions.
  • Longer 95 second actuation time keeps changes in airflow quiet and transparent.

Motor Options for incredible versatility in many different applications:

1. Standard Motor: Belimo LMB24-3-T commercial grade motor. Our most popular upgrade, the precision Swiss engineered Belimo motors offer power open power closed reliability but has a unique one wire trigger capability, making it as easy as a spring return damper to wire to a basic thermostat-with no relay needed. Two wires provide full time 24vac voltage to the motor, while the third terminal wires directly to a standard thermostat, like our Braeburn 1020 . An integral switch on this motor will even reverse damper direction, 5 year warranty, 95 second operation. The Belimo LMB24-T Motor will also stop and hold any position when power is removed, and can be used with a standard Single Pole Double Throw (SPDT) center off switch to allow easy day to day or seasonal air balancing, and has infinite blade minimum and maximum positions. Also, you may want to consider this motor if also using our Super Duty round dampers, so all motors match. Works great on zone control systems as a 3 wire damper.

2. Belimo LMB24-SR-T Modulated motor. (cost: call Retrozone) Additional fee for SGA surface mount or SGF flush mount proportional controller. -Two to ten volts DC, 4 to 20 ma modulating motor with variable position control . This is a specialty application motor that is widely used in the building automation industry for modulated control, and will not work with our standard zone control systems as offered on Ebay. Add the Belimo SGA or SGF wall mount control that enables complete range control from 0 to 100% by a simple twist of the wall mount dial control-just rotate to whatever position you want the damper in, and walk away.

3. Belimo commercial Spring Return Motor, Additional cost to basic damper above: [SEE SDTF DAMPERS] When you need two wire spring return fail safe operation but want commercial grade power and reliability, the swiss designed TF24 US spring return Motor is the motor option for you. This motor is shipped either Normally open or Normally closed, but can be field reversed by dismounting and turning over.

4. Odd Size Dampers, Additional cost to damper above. Available in one inch increments expect longer delivery times. How to order a standard damper: just buy the standard damper in the size range you want (small, medium, or large), then send us a note telling us the size you want, and what side(#long or #short) of the damper you want the motor mounted on Belimo Carrier or Trane motor (Please call factory). When selecting the motor on the short side of any damper over 24” it is considered Jackshafting. *Jackshafting requires bolting two dampers together and adding a longer shaft to control all the parts together. Current cost for Jackshafting is $32.00****Additional Time for production as well

rectangular dampers, mechanical damper, custom damper, hvac, air conditioning supplies, RetroZone

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