Ashcroft A Series - N4 Pressure Switch - Manual (Page 8)

A-S ERIES S WITCH S AFETY M ANUAL
I&M009-10210
REV A - 4/19/2013
Table1: Recommended Proof Test
Step Action
1 Bypass the safety function and take appropriate action to avoid a false trip.
2 Adjust pressure to the switch and verify that switch trips under designed
conditions.
3 Inspect the A-Series pressure switch for any visible damage or contamination.
Note that the white housing vent is still in place. (A missing vent plug is
indication of a possible pressure leak in the switch)
4 Record any failures in your company’s SIF inspection database.
5 Remove the bypass and otherwise restore normal operation.
This test will detect >90% of possible DU failures in the A-Series pressure switch.
The person(s) performing the proof test of an A-Series pressure switch should be
trained in SIS operations, including bypass procedures, switch maintenance and
company Management of Change procedures. No special tools are required.
5.2 Repair and replacement
An A-Series switch is adjustable (APA version only) but is not repairable. If a failure
has occurred the switch must be replaced. The person(s) replacing an A-Series
pressure switch should be trained in SIS operations, including bypass procedures,
switch maintenance and company Management of Change procedures.
5.3 Useful Life
The useful life of the A-Series pressure switch is 10 to 15 years, or 10,000 cycles
5.4 MANUFACTURER Notification
Any failures that are detected and that compromise functional safety should be
reported to Ashcroft. Please contact Ashcroft customer service.