Copyright RetroZone inc.2020


3085 Series Commercial Rectangular
Mechanical Damper

Starting at $183.75
Plus Free Shipping (Continental U.S.)


SD “Super Duty” 3085 Series Motorized Rectangular Power Open-

Power Closed 24vac Damper for Zone Control or HVAC Air

Control Applications, With Belimo LMB24 commercial 3 wire

damper motor-ships in 72 hours!

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 motors for more information on these motors)

Please call in your order on any of the below options, subject to change without


1. Standard motor is a Belimo LMB 95 sec motor, no extra cost.

2. SF Series Belimo Spring return motors, add $30

3. Carrier Infinity and Trane Varitrac compatible motor add $52.90

4. Belimo Motor 15 second timing Add $52.90

5. Belimo LMB-SR 0 to 10volt Modulated Add $105

* 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 at

*Available in odd sizes, one inch increments. like 9x15.

*Add on end switch available for verification or control.


*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


*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 require bottom “long side” motor mount.

Available Standard Sizes, odd sizes available


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 Robert Shaw RS2110 . 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) Add an

additional $64 for SGA surface mount or SGF flush mount proportional controller

(see pictures above) . -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, Add 20$ to cost as basic damper

above : 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, Add $10 to the basic cost of 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 an ebay or pay pal note telling us the size you

want, and what side of the damper you want the motor mounted on

Belimo Carrier or Trane motor (Please call factory)

3085S Small Size Dampers

8x6 $183.75

10x6 $183.75

12x6 $183.75

14x6 $185.85

8x8 $183.75

10x8 $183.75

12x8 $183.75

14x8 $185.85

10x10 $187.95

12x10 $187.95

14x10 $196.35

12x12 $196.35

14x12 $196.35

3085M Medium Size Dampers

16x6 $190.05

18x6 $194.25  

20x6 $196.35

22x6 $208.95

24x6 $211.05

16x8 $190.05

18x8 $194.25

20x8 $196.35

22x8 $208.95

24x8 $211.05

16x10 $194.25

18x10 $200.55

20x10 $211.05  

22x10 $213.15

16x12 $200.55

18x12 $202.65

20x12 $213.15

14x14 $200.55

16x14 $202.65  

18x14 $206.85

3085L Large Size Dampers

26x6 $207.00  

28x6 $195.00  

30x6 $211.00  

32x6 $213.00  

34x6 $215.00  

36x6 $217.00  

26x8 $205.00

28x8 $207.00

30x8 $211.00

32x8 $213.00

34x8 $215.00

36x8 $217.00

24x10 $207.00

26x10 $211.00

28x10 $213.00

30x10 $215.00

32x10 $217.00

34x10 $221.00

36x10 $223.00

22x12 $211.00

24x12 $213.00

26x12 $217.00

28x12 $219.00

30x12 $221.00

3085L Large Size Dampers

32x12 $223.00

34x12 $227.00

36x12 $229.00  

20x14 $211.00  

22x14 $215.00  

24x14 $219.00  

26x14 $223.00  

28x14 $223.00  

30x14 $227.00  

32x14 $229.00  

34x14 $223.00  

36x14 $235.00  

16x16 $203.00

18x16 $205.00

20x16 $217.00

22x16 $219.00

24x16 $223.00

18x18 $207.00

20x18 $221.00

22x18 $223.00  

24x18 $231.00

20x20 $233.00  

22x20 $233.00

24x20 $235.00

22x22 $235.00

24x22 $237.00

24x24 $239.00

3085 Small Dampers

3085 Medium Dampers

3085 Large Dampers


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