DeZurik 250 Instruction Manual - Page 5

Browse online or download pdf Instruction Manual for Controller DeZurik 250. DeZurik 250 13 pages. Diaphragm actuator iso mounting

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Open and Closed Position Stops

For closed stop adjustment on spring-to-open actuators, or open stop adjustment on spring-to-close

actuators:

1. Apply-but do not exceed-the maximum air pressure to the actuator as determined by the spring

rating shown on the actuator label.

2. Loosen the jam nut (B24) on the appropriate stop screw (B23). Refer to Figure 1.

3. Turn the stop screw in or out until the valve is in the correct position. The screw will turn easier

if the air pressure to the actuator is reduced. Reapply the maximum pressure in step 1 above to

check the stop screw adjustment.

4. Hold the stop screw from turning and tighten the jam nut to 230 ± 30 foot founds (312 ± 41 Nm)

if carbon steel or to 140 ± 18 foot pounds (190 ± 24 Nm) if stainless steel.

5. Relieve the air pressure to the actuator.

Spring Pre-Compression

Pre-compression in the 20 PSI and 35 PSI (140 kPa and 240 kPa) springs only is adjustable. The

springs are factory set so that air pressure of 5 PSI (35 kPa) less than the spring rating will just open

the valve for spring-to-close or will just close the valve for spring-to-open. Pre-compression in 60 PSI

(420 kPa) springs is not adjustable. Pre-compression settings in a 20 PSI or 35 PSI (140 kPa and 240

kPa) spring may be adjusted several PSI (kPa) by following the steps below. Refer to Figure 1 for

component identification.

1. Loosen the jam nut on the screw on the end of the spring cartridge (B8).

2. Turn the screw clockwise to increase the pre-compression; turn the screw counterclockwise to

decrease the pre-compression.

3. Hold the screw from turning and tighten the jam nut to 340 ± 45 foot pounds (460 ± 60 Nm).

Refer to Figure 1 for component identification.

1. Relieve the air pressure and disconnect the air line from the actuator. The actuator spring will

open (for spring-to-open) or close (for spring-to-close) the valve.

2. Remove the diaphragm cover screws (B15), nuts (B16) and washers (B42); remove the

diaphragm cover (B11) and diaphragm (B14).

3. Place the new diaphragm in position on the lower diaphragm cover (B12). Align the holes in the

diaphragm with the holes in the cover.

4. Place the diaphragm cover (B11) in position on the diaphragm. Align the holes in the cover with

the holes in the diaphragm and in the lower diaphragm cover.

5. Replace the cover screws (B15), nuts (B16) and washers (B42) in the holes and tighten all the

screws evenly until the diaphragm is in contact with both covers, then tighten the screws in a

crisscross pattern to 12 ± 2 foot pounds (16 ± 3 Nm) for the Model 145 or 18 ± 2 foot pounds

(24 ± 3 Nm) for the Model 250.

6. Reconnect the air line to the actuator. Service may be resumed.

September 2015

DeZURIK MODELS 145 AND 250 DIAPHRAGM ACTUATOR ISO MOUNTING

(continued)

Page 5

DeZURIK

D10368