Belimo LF120 US Instruction Manual

J20741 - Subject to change. © Belimo Aircontrols (USA), Inc.
Torque min. 35 in-lb, for control of air dampers
Application
For on-off, fail-safe control of dampers in HVAC systems.
Actuator sizing should be done in accordance with the damper
manufacturer’s specifications. Control is on-off from an auxil-
iary contact, or a manual switch.
The actuator is mounted directly to a damper shaft from 3/8”
up to 1/2”in diameter by means of its universal clamp, 1/2”
shaft centered at delivery. For shafts up to 3/4”use K6-1
accessory. A crank arm and several mounting brackets are
available for applications where the actuator cannot be direct
coupled to the damper shaft.
Operation
The LF series actuators provide true spring return operation for
reliable fail-safe application and positive close off on air tight
dampers. The spring return system provides consistent torque
to the damper with, and without, power applied to the actuator.
The LF series provides 95°of rotation and is provided with a
graduated position indicator showing 0°to 95°.
The actuator may be stalled anywhere in its normal rotation
without the need of mechanical end switches. Power con-
sumption is reduced in holding mode. The actuator is double
insulated so an electrical ground connection is not necessary.
The LF120-S US and LF230-S US versions are provided with
1 built-in auxiliary switch. This SPDT switch is provided for
safety interfacing or signaling, for example, for fan start-up.
The switching function is adjustable between 0°and 95°.
Dimensions [All numbers in brackets are in millimeters.]
LF120 (-S) US / LF230 (-S) US
On-off, Spring Return Fail-Safe, 120/230 VAC
Technical Data LF120 (-S) US LF230 (-S) US
Power supply 120 VAC ± 10% 230 VAC ± 10%
50/60 Hz 50/60 Hz
Power consumption running: 5.5 W 5 W
holding: 3.5 W 3 W
Transformer sizing 7.5 VA 7 VA
Electrical connection 3 ft, 18 GA appliance cable
(-S models have 2 cables)
1/2”conduit connector
Overload protection electronic throughout 0 to 95°rotation
Electrical protection actuators are double insulated
Angle of rotation max 95°, adjust. with mechanical stop
Torque 35 in-lb [4 Nm] constant torque
Direction of rotation reversible with cw/ccw mounting
Position indication visual indicator, 0°to 95°(0°is
spring return position)
Auxiliary switch 1 x SPDT 3A (0.5A) @ 250 VAC,
UL listed
(-S models) adjustable 0°to 95°
Electrical protection actuators are double insulated
Running time motor: < 40 to 75 sec
spring:< 25 sec
@-4°F to +122°F [-20°C to +50°C]
< 60 sec @-22°F [-30°C]
Humidity 5 to 95% RH non-condensing
Ambient temperature -22°F to +122°F [-30°C to +50°C]
Storage temperature -40°F to +176°F [-40°C to +80°C]
Housing NEMA type 2 / IP54
Housing material zinc coated steel
Agency listings UL 873, CSA C22.2 No. 24 Certified,
CE [LF230(-S) US]
Noise level max: running < 50 db (A)
spring return 62 dB (A)
Servicing maintenance free
Quality standard ISO 9001
Weight LF120/230 3.4 lbs (1.54 kg)
LF120/230-S 3.5 lbs (1.60 kg)
®
(nominal)
LISTED
94D5
TEMP. IND &
REG. EQUIP.
UL

68
0.39" [10]
7.67" [195]
3.66" [93]
1.93"
[49]
6.10" [155]
3.15" [80]
3.86"
[98]
0.256" [6.5] 0.98"
[25]
4.92" [125]
0.79"
[20]
0.5"
[12.7]
0.71" [18]
0.74" [18.7]
2.24"
[57]
3.23" [82]
0.25" [6.3]
Standard:
3/8" to 1/2"
3/8" to 7/16"
Optional
1/2" to 3/4"
w/K6-1
accessory
D010

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J20741 - Subject to change. © Belimo Aircontrols (USA), Inc.
LF
LF120 (-S) US / LF230 (-S) US
On-off, Spring Return Fail-Safe, 120/230 VAC
Accessories
AV 10-18 Shaft extension (K6-1 is required)
IND-LF Damper position indicator
K6-1 Universal clamp for up to 3/4”diameter shafts
KH-LF Crankarm for up to 1/2”round shaft
Tool-06 8mm and 10 mm wrench
ZG-LF2 Crankarm adaptor kit for LF
ZG-112 Mounting bracket for Honeywell Mod IV, M6415
type actuators, and new installations
ZG-LF112 Crankarm adaptor kit for Honeywell Mod IV,
M6415 type actuators, and new installations
ZS-100 Weather shield (metal)
ZS-150 Weather shield (polycarbonate)
ZS-260 Explosion-proof housing
Note: When using LF120/230 US and LF120-S/230-S US
actuators, only use accessories listed on this page.
For Actuator Wiring Information and Diagrams,
Please See Belimo Wiring Guide (pg 349).
LF120 (-S) US / LF230 (-S) US Typical Specification
On-off spring return damper actuators shall be direct coupled
type which require no crankarm and linkage and be capable of
direct mounting to a shaft up to a 3/4”diameter and center a
1/2”shaft. The actuators must be designed so that they may be
used for either clockwise or counterclockwise fail-safe opera-
tion. Actuators shall be protected from overload at all angles
of rotation. If required, 1 SPDT auxiliary switch shall be provid-
ed having the capability of being adjustable. Actuators must be
constructed to meet the requirements for Double Insulation so
an electrical ground is not required to meet agency listings.
Actuators shall be UL listed and CSA certified, have a 5 year
warranty, and be manufactured under ISO 9001 International
Quality Control Standards. Actuators shall be as manufac-
tured by Belimo.
Wiring Diagrams
2
1Provide overload protection and disconnect as required.
Actuators may be connected in parallel. Power con-
sumption must be observed.
No ground connection is required.
2
3
1
3
Provide overload protection and disconnect as required.
Actuators may be connected in parallel. Power con-
sumption must be observed.
No ground connection is required.
For end position indication, interlock control, fan start-
up, etc., LF120-S US and LF230-S US incorporate
one built-in auxiliary switch: 1 x SPDT, 3A (0.5A)
@250 VAC, UL listed, adjustable 0°to 95°.
Meets UL and CSA requirements without the need of an
electrical ground connection.
®
4
5
On-off wiring for LF120 US / LF230 US On-off wiring for LF120-S US / LF230-S US
1 Neutral
2 Hot
1
2
120 VAC
230 VAC
LF120 US
LF230 US
3
L1 N
L2 H
1 Neutral
2 Hot
2
3
4
5
5
S1
S2
S3
NC
NO
0°to 95°
LF120-S US
LF230-S US
1
120 VAC
230 VAC
L1 N
L2 H
W049
W050

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J20741 - Subject to change. © Belimo Aircontrols (USA), Inc.
Preliminary steps
1. Belimo actuators should be mounted indoors in dry, rela-
tively clean environment free from corrosive fumes. If the
actuator is to be mounted outdoors, a protective enclosure
must be used to shield the actuator. (See Belimo
Mechanical Accessories )
2. For new construction work, order dampers with extended
shafts. Instruct the installing contractor to allow space for
mounting and service of the Belimo actuator on the shaft.
3. For standard mounting, the damper shaft must extend at least
3 1/2" from the duct. If the shaft extends less than 3 1/2", the
actuator may be mounted in its
short shaft configuration. If an
obstruction blocks access, the
shaft can be extended with the
AV 10-18 shaft extension. (K6-1 is required)
Installation Instructions
Quick-Mount Visual Instructions
min 3 1/2”
[90]
min 3 1/2”
[90]
min 3/4”
[20]
IND-LF Position Indicator
(optional)
min 3/4”
[20]
IND-LF Position Indicator
(optional)
1. Rotate the damper to its failsafe position. If the shaft rotates
counterclockwise, mount the “CCW”side of the actuator out. If it
rotates clockwise, mount the actuator with the “CW”side out.
2. If the universal clamp is not on the correct side of the actua-
tor, move it to the correct side.
3. Slide the actuator onto the shaft and tighten the nuts on the
V-bolt with a 10mm wrench to 6-8 ft-lb of torque.
4. Slide the anti-rotation strap under the actuator so that it
engages the slot at the base of the actuator. Secure the
strap to the duct work with #8 self-tapping screws.
NOTE: Read the “Standard Mounting”instructions, on the next
page, for more detailed information.
min 3 1/2”
[90]
min 3/4”
[20]
®
Standard
Mounting Short Shaft Mounting
Dimensions [All numbers in brackets are in millimeters.]

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J20741 - Subject to change. © Belimo Aircontrols (USA), Inc.
LF
1. See Fig. B. Manually move the damper to the fail-safe
position (a) (usually closed). If the shaft rotated counter-
clockwise ( ), this is a CCW installation. If the shaft
rotated clockwise ( ), this is a CW installation. In a
Left Hand installation, the actuator side marked “CW”
faces out, while in a CW installation, the side marked
“CCW”faces out. All other steps are identical.
2. The actuator is usually shipped with the universal clamp
mounted to the “CW”side of the actuator. To test for
adequate shaft length, slide the actuator over the shaft
with the side marked “CW”(or the “CCW”side if this is the
side with the clamp). If the shaft extends at least 1/8”
through the clamp, mount the actuator as follows. If not,
go to the Short Shaft Installation section.
3. If the clamp is not on the correct side as determined in step
#1, re-mount the clamp as follows. If it is on the correct
side, proceed to step #5. Look at the universal clamp. If
you are mounting the actuator with the “CCW”side out,
position the clamp so that the pointer section of the tab is
pointing to 0°(see Fig. C) and the spline pattern of the
clamp mates with spline of the actuator. Slip the clamp over
the spline. (Use the same procedure if the “CW”side is
out.)
4. Lock the clamp to the actuator using the retaining clip.
5. Verify that the damper is still in its full fail-safe position. (a)
6. Mount the spring return actuator to the shaft. Tighten the
universal clamp, finger tight only.
7. Mount the anti-rotation strap at the base of the actuator.
Do not tighten the screws.
8. Remove the screw from one end of the mounting bracket
and pivot it away from the actuator.
9. Loosen the universal clamp and, making sure not to move
the damper shaft, rotate the actuator approximately 5°in
the direction which would open the damper.
10. Tighten the universal clamp to the shaft.
11. Rotate the actuator to apply pressure to the damper seals
(b) and re-engage the anti-rotation strap (c).
12. Tighten all fasteners.
Installation Instructions
Standard Mounting / Airtight Damper Procedure
Mechanical Operation
The actuator is mounted directly to a damper shaft up to 1/2”in diameter by means of its universal clamp, or up to a 3/4”shaft with
the optional K6-1 clamp. A crank arm and several mounting brackets are available for applications where the actuator cannot be
direct coupled to the damper shaft.
The LF series actuators provide true spring return operation for reliable fail-safe application and positive close-off on air tight
dampers. The spring return system provides consistent torque to the damper with, and without, power applied to the actuator.
The LF series provides 95°of rotation and is provided with a graduated position indicator showing 0 to 95°.
The LF…-S versions are provided with 1 built-in auxiliary switch. This SPDT switch is provided for safety interfacing or signaling, for
example, for fan start-up. The switching function is adjustable between 0°and 95°.
Universal
Clamp
0
.2
.4
.6
.8
1
Fig. BFig. C
0
1
2
4
5
6
7
89
L
C
b
c
a
.2
.4
.6
.8
1
CW
0
®
Standard
Mounting
Standard
Mounting
min 3 1/2”
[90]
®

90
J20741 - Subject to change. © Belimo Aircontrols (USA), Inc.
®
If the shaft extends at least 3/4”from the duct, follow these
steps:
1. (See Fig. D) Move damper blades to the fail-safe position (a).
2. Determine the best orientation for the universal clamp on the
back of the actuator. The best location would be where you
have the easiest access to the V bolt nuts on the clamp.
3. Engage the clamp to the actuator as close as possible to
the determined location.
4. Lock the clamp to the actuator using the retainer clip.
5. Mount the spring return actuator to the shaft. Tighten the
universal clamp, finger tight only.
6. Mount the anti-rotation strap at the base of the actuator.
Do not tighten the screws.
7. Remove the screw from one end of the mounting bracket
and pivot it away from the actuator.
8. Loosen the universal clamp and, making sure not to move
the damper shaft, rotate the actuator approximately 5°in
the direction which would open the damper.
9. Verify that the damper is still in its full fail-safe position.
10. Tighten the universal clamp to the shaft.
11. Rotate the actuator to apply pressure to the damper seals
(b) and re-engage the anti-rotation strap (c).
12. Tighten all fasteners.
13. Use IND-LF accessory if position indication is needed.
Installation Instructions
Short Shaft Mounting with IND-LF Position Indicator / Airtight Damper Procedure
Initialization of the LF24-SR US and LF24-MFT…US
When power is applied, the internal microprocessor recog-
nizes that the actuator is at its full fail-safe position and
uses this position as the base for all of its position calcula-
tions. This procedure takes approximately 15 seconds.
During this time you will see no response at the actuator.
The microprocessor will retain the initialized zero during
short power failures of up to 25 seconds. When power is
applied during this period, the actuator will return to normal
operation and proceed to the position corresponding to the
input signal provided. For power failures over 25 seconds,
the actuator will be at it fail-safe position and will go through
the start up initialization again.
Motor position detection
Belimo brushless DC motors eliminate the need for poten-
tiometers for positioning. Inside the motor are three “Hall
Effect”sensors. These sensors detect the spinning rotor
and send pulses to the microprocessor which counts the
pulses and calculates the position to within 1/3 of a revolu-
tion of the motor.
Overload protection
The LF, on-off actuators are electronically protected against
overload. The LF, On-off actuators have an internal current
limiter which maintains the current at a safe level which will
not damage the actuator while providing adequate holding
torque.
The LF24, modulating actuators (LF24-SR US, LF24-3 US,
LF24-MFT US) are protected against overload by digital tech-
nology located in the ASIC. The ASIC circuitry constantly mon-
itors the rotation of the brushless DC motor inside the actuator
and stops the pulsing to the motor when it senses a stall con-
dition. The motor remains energized and produces full rated
torque during stall conditions. The actuator will try to move in
the direction of the stall every 2 minutes, for a period of 32
minutes. After this, the actuator will try again every 2 hours.
Operational Information for LF24-SR US and LF24-MFT…US Actuators
min 3/4”
[20]
IND-LF Position Indicator
(optional)
Fig. D
0
1
2
4
5
6
7
89
L
C
b
c
a
.2
.4
.6
.8
1
CW
0
®
Short Shaft
Mounting
Short Shaft
Mounting

91
J20741 - Subject to change. © Belimo Aircontrols (USA), Inc.
LF
®
The LF actuators are provided with an adjustable stop to limit
the rotation of the actuator. This function works in conjunction
with the universal clamp or the optional position indicator.
The adjustable stop is needed when rotation of less than 95°
is required. The LF actuator can be indefinitely stalled, in any
position, without harming the actuator.
Using the universal clamp:
1. Loosen the end stop fastening screw using a #2 Phillips
screwdriver.
2. Move the stop block so the bottom edge of the block lines
up with the number corresponding to the desired degrees
of rotation. (example: 45 degrees of rotation = .5)
3. Lock the block in place with the fastening screw.
4. Check the actuator for proper rotation.
Using the IND-LF position indicator with adjustable stop:
Note: preferred method if short shaft mounting is used.
1. With the actuator in its fail-safe position, place the IND-LF
Position Indicator so that it points to the 0 degree position.
2. Loosen the end stop fastening screw using a #2 Phillips
screwdriver.
3. Move the stop block so the bottom edge of the block lines
up with the number corresponding to the desired degrees
of rotation. (example: 45 degrees of rotation = .5)
4. Lock the block in place with the fastening screw.
5. Check the actuator for proper rotation.
0
.2
.4
.6
.8
1
Mechanical Angle of Rotation Limiting
Installation Instructions
Quick-Mount Visual Instructions for Mechanical Installation
LF24-SR US actuators have built-in brushless DC motors which provide better accuracy and longer service life.
The LF24-SR US actuators are designed with a unique non-symmetrical deadband. The actuator follows an increasing or
decreasing control signal with a 80 mV resolution. If the signal changes in the opposite direction, the actuator will not respond
until the control signal changes by 200 mV. This allows these actuators to track even the slightest deviation very accurately,
yet allowing the actuator to “wait”for a much larger change in control signal due to control signal instability.
Control Accuracy and Stability
Satisfied
Control Position
Satisfied
Control Position
Minimum
Control Resolution
Minimum Reversed
Control Deadband
Prior to Normal Control
80 mV
200 mV
LF Actuator responds to a 80 mV signal when
not changing direction from stop position. LF Actuator responds to a 200 mV signal when reversing direction from stop position.
LF24-3 (-S) US and LF24-SR (-S) USactuators have a direction of
rotation switch on the cover labeled “CW-CCW”. Switch position
indicates start point. For the LF24-SR, with the switch in position
“CW”, the actuator rotates clockwise with a decrease in voltage or
current. With the switch in position “CCW”, the actuator rotates
counterclockwise with a decrease in voltage or current.
The LF24-3 (-S) US and LF24-SR (-S) US actuators rotate clock-
wise when the switch is in the “CW”position and power is applied
to wire #3. When power is applied to wire #4 the actuator rotates
counter clockwise.
Rotating the direction of rotation switch to “CCW”reverses the
control logic.
During checkout, the switch position can be temporarily
reversed and the actuator will reverse its direction. This allows
the technician a fast and easy way to check the actuator oper-
ation without having to switch wires or change settings on the
controller. When the check-out is complete, make sure the
switch is placed back to its original position.
Direction of Rotation Switch
The LF24-MFT(-S) US control accuracy and stability can be found in the MFT specifications, page 293.

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®
Installation Instructions
The …-S model actuators are equipped with an adjustable
auxiliary switch used to indicate damper position or to inter-
face additional controls or equipment. Switching positions can
be set over the full 0 to 95°rotation simply by setting a switch
on the actuator.
1. Set desired switch position. (Example 60%)
2. As the actuator rotates, the switch indicator moves from .6
(60%) toward 0 (0%). When the indicator passes 0 the
switch contact between S1 and S2 is broken and the con-
tact between S1 and S3 is made.
Auxiliary Switches
.8
.6
.4
.2
0
1
S1 S2
S3
S1 S2
S3
Non-direct Mounting Methods
KH-LF crankarm including retaining ring.
KH-LF
For shafts up to 1/2”
ZG-112
(pushrod not supplied with kit)
KG6 ball joint and
universal crankarm
(not included)
KG6 ball joint
(not included)
KH-LF
crankarm
KH-LF
crankarm
ZG-LF2
Crankarm adaptor kit
ZG-LF112
Crankarm adaptor kit
Voltage Resistive load Inductive load
120 VAC 3 A 1.03 A
250 VAC 3 A 0.5 A
Switch Rating

93
J20741 - Subject to change. © Belimo Aircontrols (USA), Inc.
LF
®
WARNING The wiring technician must be trained and experi-
enced with electronic circuits. Disconnect power supply
before attempting any wiring connections or changes. Make
all connections in accordance with wiring diagrams and follow
all applicable local and national codes. Provide disconnect
and overload protection as required. Use copper, twisted pair,
conductors only. If using electrical conduit, the attachment to
the actuator must be made with flexible conduit.
Always read the controller manufacturer's installation lit-
erature carefully before making any connections. Follow
all instructions in this literature. If you have any questions,
contact the controller manufacturer and/or Belimo.
Transformer(s)
The LF24 . . actuator requires a 24 VAC class 2 transformer
and draws a maximum of 7 VA per actuator. The actuator
enclosure cannot be opened in the field, there are no parts or
components to be replaced or repaired.
–EMC directive: 89/336/EEC
–Software class A: Mode of operation type 1
–Low voltage directive: 73/23/EEC
CAUTION: It is good practice to power electronic or digital
controllers from a separate power transformer than that used
for actuators or other end devices. The power supply design
in our actuators and other end devices use half wave rectifica-
tion. Some controllers use full wave rectification. When these
two different types of power supplies are connected to the
same power transformer and the DC commons are connected
together, a short circuit is created across one of the diodes in
the full wave power supply, damaging the controller. Only use
a single power transformer to power the controller and actua-
tor if you know the controller power supply uses half wave rec-
tification.
Multiple Actuators, One Transformer
Multiple actuators may be powered from one transformer pro-
vided the following rules are followed:
1. The TOTAL current draw of the actuators (VA rating) is
less than or equal to the rating of the transformer.
2. Polarity on the secondary of the transformer is strictly fol-
lowed. This means that all No. 1 wires from all actuators
are connected to the common leg on the transformer and
all No 2 wires from all actuators are connected to the hot-
leg. Mixing wire No. 1 & 2 on one leg of the transformer
will result in erratic operation or failure of the actuator
and/or controls.
Multiple Actuators, Multiple Transformers
Multiple actuators positioned by the same control signal may
be powered from multiple transformers provided the following
rules are followed:
1. The transformers are properly sized.
2. All No. 1 wires from all actuators are tied together and tied
to the negative leg of the control signal. See wiring diagram.
Wire Length for LF…Actuators
Keep power wire runs below the lengths listed in the table in
Fig. A. If more than one actuator is powered from the same
wire run, divide the allowable wire length by the number of actu-
ators to determine the maximum run to any single actuator.
Example for LF24-SR US:
3 actuators, 16 Ga wire
550 Ft ÷3 Actuators = 183 Ft. Maximum wire run
Maximum Wire Length:
Wire Size Max. Feet. Wire Size Max. Feet
12 Ga 1100 Ft. 18 Ga 260 Ft.
14 Ga 700 Ft. 20 Ga 140 Ft.
16 Ga 440 Ft. 22 Ga 75 Ft.
Fig. A
Wire Type and Wire Installation Tips
For most installations, 18 or 16 Ga. cable works well with the
LF24…actuators. Use code-approved wire nuts, terminal
strips or solderless connectors where wires are joined. It is
good practice to run control wires unspliced from the actuator
to the controller. If splices are unavoidable, make sure the
splice can be reached for possible maintenance. Tape and/or
wire-tie the splice to reduce the possibility of the splice being
inadvertently pulled apart.
The LF24…proportional actuators have a digital circuit that is
designed to ignore most unwanted input signals (pickup). In
some situations the pickup may be severe enough to cause
erratic running of the actuator. For example, a large inductive
load (high voltage AC wires, motors, etc.) running near the
power or control wiring may cause excessive pickup. To solve
this problem, make one or more of the following changes:
1. Run the wire in metallic conduit.
2. Re-route the wiring away from the source of pickup.
3. Use shielded wire (Belden 8760 or equal). Ground the
shield to an earth ground. Do not connect it to the actua-
tor common.
Brushless DC Motor Operation
Belimo's brushless DC motor spins by reversing the poles of
stationary electromagnets housed inside rotating permanent
magnets. The electromagnetic poles are switched by a micro-
processor and a special ASIC (Application Specific Integrated
Circuit) developed by Belimo. Unlike the conventional DC
motor, there are no brushes to wear or commutators to foul.
Wire Size Max. Feet. Wire Size Max. Feet
12 Ga 1500 Ft. 18 Ga 375 Ft.
14 Ga 925 Ft. 20 Ga 200 Ft.
16 Ga 550 Ft. 22 Ga 100 Ft.
Installation Instructions
General Wiring
LF24 (-S) US
LF120 (-S) US / LF230 (-S) US
LF24-SR (-S) US / LF24-3 (-S) US / LFC24-3-R (-S) US /
LF24-MFT…US
Wire Size Max. Feet. Wire Size Max. Feet
12 Ga 1250 Ft. 18 Ga 320 Ft.
14 Ga 800 Ft. 20 Ga 160 Ft.
16 Ga 500 Ft. 22 Ga 85 Ft.

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®
Startup and Checkout
Instructions For LF24-SR (-S) US and LF24-MFT…US + P100
Procedure
Remove power to reset actuator.
Re-apply power.
Apply control signal to actuator.
Check power wiring. Correct any
problems. See Note 1.
Turn reversing switch to the correct
position. Make sure the switch is
turned all the way left or right.
Make sure the control signal positive
(+) is connected to Wire No 3 and
control signal negative (-) is connect-
ed to wire No. 1. Most control prob-
lems are caused by reversing these
two wires. Verify that the reversing
switch is all the way CCW or CW.
Check input signal with a digital volt
meter (DVM). Make sure the input is
within the range of the actuator. For
LF24-SR US this is 2 to 10 VDC or
4 to 20 mA. Note: The input signal
must be above the 2 VDC or 4 mA to
have the actuator move.
Loosen the nuts on the V-bolt and
move the damper by hand from fully
closed to fully open.
Check damper torque requirement.
Actuator works properly. Test
controller by following controller
manufacturer's instructions.
Expected Response
Actuator will move to its “Control
Signal”position.
Power supply rating should be ≥
the total power requirement of
the actuator(s). Minimum volt-
age of 19.2 VAC or 21.6 VDC.
Actuator will move to its “Control
Signal”position.
Drives to “Control Signal”
position
Input voltage or current should be
±1% of what controller's adjust-
ment or programming indicate.
Damper will go from fully closed
to fully open.
Torque requirement is ≤actua-
tor’s minimum torque.
Gives Expected
Response
Go To Step…
Actuator operates
properly
Step 8.
Power wiring correct-
ed, actuator begins
to drive
Step 1.
Actuator operates
properly.
Step 8.
Actuator operates
properly
Step 8.
Controller output
(actuator input) is
correct. Input
Polarity Correct
Step 6.
Damper moves
properly
Step 7.
Defective Actuator.
Replace Actuator -
See Note 2.
Does Not Give
Expected Response
Go To Step…
No response at all
Step 2.
Operation is
reversed
Step 3.
Does not drive
toward "Control
Signal Position"
Step 4.
Power wiring
corrected, actuator
still does not drive
Step 4.
Does not drive
toward “Control
Signal Position”
Step 4.
Step 5.
Reprogram, adjust
repair or replace
controller as needed
Step 1.
Find cause of damper
jam and repair. Move
damper back to the
fully closed position
and tighten the nuts
Step 1.
Recalculate actuator
requirement and
correct installation.
Step
1.
2.
3.
4.
5.
6.
7.
8.
Note 1 Check that the transformer(s) are sized properly.
•If a common transformer is used, make sure that polarity is observed on the secondary. This means connect all No. 1
wires to one leg of the transformer and all No. 2 wires to the other leg of the transformer.
•If multiple transformers are used with one control signal, make sure all No. 1 wires are tied together and tied to control
signal negative (-).
•Controllers and actuators must have separate 24 VAC/VDC power sources.
Note 2 If failure occurs within 5 years from original installation date, notify Belimo and give details of the application.
LF24-SR (-S) US and LF24-MFT…US + P100 Electrical check-out procedure