Specifications

ManualsBrandsComtrol ManualsAccessories communicationES8108

CHECKOUT

After installation, the actuator should be checked to insure

proper damper operation. To check the actuator and linkage,

proceed as follows:

1. Check the linkage with the actuator in the retracted

position for proper return force. The actuator should be

linked so that on a normally closed application, the damper

is closed with no more than 1/16-inch compression of the

spring. (The actuator shaft would return an additional

1/16-inch if the linkage were disconnected.) For a normally

open application, the actuator should be linked with the

actuator fully retracted.

2. Apply air pressure to the actuator or pilo

t port of a

positioner and check the linkage as follows. On a

normally closed application, the damper should be just

full open when the actuator piston reaches the stops in

the actuator. On a normally open application, the damper

should reach the closed position with no more than

1/16-inch stroke remaining to reach the actuator stops.

3. The above can be obtained through adjustment of the ball

joint in the crank

arms or by adjustment of the actuator

stops. The amount of thread engagement of the actuator

ball joint or extension shaft may also be used to assist in

proper linking.

Connection of Air Line: On pivot mounting arrangements,

Figures 9, 10 and 12, control air lines MUST be terminated at

the actuator with at least 6 inches of flexible tubing to allow for

pivoting of the actuator. On mounting arrangements, Figures

5, 7 and 8, control air lines may be connected directly with

either copper or plastic tubing, as required by application.

Caution: On MK2-31X1 Series, metal connectors and tubing

must be used.

Adjustable Starting Pressure: Actuators are available with

adjustable starting pressure. To adjust the starting pressure,

turn adjusting nut supporting the spring clockwise to increase

and counterclockwise to decrease the starting pressure. Each

rotation of the adjusting nut changes the starting pressure .04

psi (.28 kPa).

Adjustable Stroke Length: S

troke length is determined by

the two stops located on either side of the actuator. Stops are

set for 3-1/2-inch stroke. mark this point and measure toward

the diaphragm end of the actuator to reduce the stroke or

away from the diaphragm end to increase the stroke.

Maximum stroke length is 4 inches. By increasing the stroke

length, the force available to resist an opposing force is

decreased while decreasing the stroke length increases this

force.

Diaphragm Replacement: If

the actuator diaphragm should

leak, it may easily be replaced by removing the four screws

holding the top power housing. Make sure that shaft swivel

joint is in place on the end of the shaft. Remove the screws

and old diaphragm. Roll the new diaphragm inside out and

install over the piston making sure the circular bead is facing

up. Put the top power housing back in place making sure the

bead on the diaphragm is in the housing groove and the screw

holes are lined up. Tighten housing screws.

UNITS WITH FACTORY MOUNTED

POSITIVE POSITIONERS

Figure-16 Typical Factory Mounted Positioner.

For Actuators with Positioners:

Note: If actuator is frame pivot mounted, the actuator must

be mounted to the left-hand frame. If actuator is mounted

external, Figure 12 must be on right-hand side of duct.

Install fittings required in Ports 2 and 3.

ADJUSTMENTS

Refer to Figure 16.

Range Adjustment: Adjustable 2 to 10 psig (14 to 69 kPa).

Factory set at 5 psig (34 kPa). Range is the pressure change

required to produce full actuator stroke.

If adjustment is required (see Figure 16), with a small

screwdriver loosen screw on range slider approximately 1/2

turn.

Move the graduated range slider until desired pressure mark

lines up with center of screw and tighten screw.

Start Point: Adjustable 2 to 10 psig (14 to 69 kPa). Start point

is the pressure at which the actuator just begins to extend.

See Figure 16.

Connect main air supply to Port 3 and a variable air supply to

Port 2.

1. Adjust variable air supply on Port 2 to desired start point

pressure.

2. Adjust the start point screw with small screwdriver until

actuator just starts to extend.

3. Gradually raise pressure on Port 2 until actuator is fully

extended, and readjust range slider to obtain desired

range if further adjustment is necessary.

4. Remove variable air supply from Port 2 and connect to

controller output.