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7.3
Microswitch Replacement
If the Microswitch should fail during normal operation it can be easily replaced in the field using the
following procedure:
1. Make sure that the power supply to the Pressure Switch is turned off.
2. Remove the Cap from the Switch Housing (use break-out slots in the Cap if required).
3. Disconnect all the electrical wires from the Microswitch and tuck them out of the way.
4. Using a 3/16" T-Handle hexagonal wrench, loosen and remove the Switch Block Locking Screw.
5. Lift out the entire Microswitch sub-assembly.
6. Place the new Microswitch sub-assembly in the Switch Housing and tighten the Switch Block Locking
7. Re-attach all the electrical wires to the Microswitch as they were before. (Refer to Argus Wiring
8. If necessary, make adjustments to the Leaf Spring. Use a flat blade screwdriver to tighten the Leaf
9. Install the Cap on the Switch Housing and tighten until the Cap shoulders with the Switch Housing.
10. Turn on the power supply to the Pressure Switch.
8.0
Maintenance
Argus recommends that a preventive maintenance program be implemented to ensure the longevity of the
Pressure Switch.
•
Argus recommends that the operator periodically (quarterly) test each Pressure Switch to ensure that it is
working properly.
•
Tests may consist of a pressure test and verification of unit shutdown.
•
For a Pressure Switch that is set for increasing pressure the operator may close a valve downstream and
check that the Switch trips off at the appropriate set point. If the set point is incorrect, the operator
should adjust it to the original setting. (See Section 7.2 Pressure Setting).
•
For a Pressure Switch that is set for decreasing pressure the operator may close a valve upstream and
check that the Switch trips off at the appropriate set point. If the set point is incorrect, the operator
should adjust it to the original setting. (See Section 7.2 Pressure Setting).
•
The Pressure Switch may also be taken off the line and sent to an Argus Service Center for testing and
adjustment.
•
Visually check for excessive moisture in the Bottom Sub, by looking in the Access Port. If excessive moisture
is present the Pressure Switch should be cleaned and serviced by Argus or one of their approved Service
Centers.
6
Seal Block and the cap screw and fix with a leaded seal. If the seal is broken, tampering may have
occurred and the set point should be checked.
Screw with the 3/16" T-Handle hexagonal wrench.
Caution: Do not over-tighten, as damage may occur.
Instructions Bulletin No. TB-PS-002).
Spring Adjusting Screw clockwise until it shoulders. Turn the Adjusting Screw counterclockwise
until you hear the Microswitch trip off (approximately 3 turns). Turn the Adjusting Screw 1 1/2 turns
clockwise to set.
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