3

42-686 Series K Pneumatic Switch Mechanism

5.0

Preventive Maintenance

5.0.1 Nozzle cleaning

To clean the nozzle, follow the steps below:

1. Unscrew and remove the adapter. Refer to Figure 5.

Caution: Do not lose the ball which will drop out when the adapter

is removed.

2. The ball and actuating rod will now fall out when the

switch is tipped.

will prevent damage to the flapper when performing step 4.

connection side. Refer to Figure 6. The wire may be moved

back and forth to clean the opening of any accumulated

matter.

5. Reassemble the actuating rod, ball, and adapter; insert into

nozzle. Refer to Figure 5.

6. Securely tighten the air line adapter.

7. Readjust the flapper to its original position; refer to Nozzle

Flapper Readjustment procedure.

5.0.2 Nozzle flapper readjustment

1. Connect an air line to the adapter.

2. Pressurize the air line.

3. Adjust the flapper with the socket set screw for the desired

action:

Direct Action

A. Hold the magnet against the enclosing tube.

the air flow stops, plus an extra one-eighth turn.

Reverse Action

A. Hold the magnet tab against the fall out stop. Refer to

Figure 3.

the air flow stops.

4. Manually actuate the switch under pressure to assure its cor-

rect actuation. The unit is now ready for service.

5. Operate control at normal process conditions to verify

adjustments.

Figure 6

Figure 5

wrench

Actuating rod

Enclosing tube

Socket set

screw

Air line

adapter

Ball

Nozzle

1

Flapper

Enclosing tube

Socket set screw

Nozzle

Flapper

Magnet

(yellow

or red

dot)