SOR Single Diaphragm Weatherproof Differential Pressure Switch with Terminal Block Connections - Manual (Page 6)

6/12 Form 506 (01.13) ©SOR Inc.
Set Point OK
If contacts break precisely at critical decreasing
differential pressure set point, repeat steps

-

as desired to verify calibration.
Calibration is complete.
Normal Operating
Differential Pressure
Make
Critical Decreasing
Set Point
Differential Pressure
Break
Contacts Open - Set Point Too High
If contacts are open when critical decreasing
differential pressure is reached, turn set point
adjustment counterclockwise (out) until contacts make.
From this point, turn set point adjustment clockwise
(in) until contacts break. Repeat Steps

-

.
Make
Break
Normal Operating
Differential Pressure
Contacts Closed - Set Point Too Low
If contacts are closed when critical increasing
differential pressure is reached, turn set point
adjustment clockwise (in) until contacts break.
Repeat Steps

-

.
Break
Normal Operating
Differential Pressure
Critical Decreasing
Set Point
Make
0 Time
Critical Decreasing
Set Point
Differential Pressure
Differential Pressure
For Critical Set Point on Decreasing Differential Pressure

Connect the continuity test lamp or ohmmeter across the C - Common and NO - Normally
Open contacts.

Close the bleed valve(s), open the equalizer valve, and raise pressure equally on both HI
and LO sides to the normal operating high side pressure.

With normal HI side pressure stable, close the equalizer valve to isolate the HI side from
the LO side.

Slightly open the LO side bleed valve to reduce LO side pressure (increase differential
pressure) until the normal operating differential pressure appears on the digital indicator.
Close the bleed valve to stabilize differential pressure. Contacts should close (make) by
the time normal operating differential pressure is reached. If the contacts are still open
at normal operating differential pressure, turn the set point adjustment counterclockwise
(out) until the contacts make.

Keeping the high side pressure steady, slightly open the equalizer valve to increase LO side
pressure (decrease differential pressure) until the desired differential pressure set point
appears on the digital indicator. Close the equalizer valve to stabilize differential pressure.
Check the status of the electrical contacts against the following differential pressure trend
graphs. Follow the instructions under the graph that matches the status of the contacts.