SOR Thermal Differential Flow Switch - Manual (Page 8)

8/12 Form 1024 (08.13) ©SOR Inc.
NOTE: This adjustment may be done for tripping points between 10% and 90% of the span from
no fl ow to max fl ow.
Calibration for Flow Switches
Using as a location guide, adjust the system as follows:

Remove instrument enclosure lid by turning it counterclockwise.

Apply power to the T21. Allow 5-minute warm-up. Verify J1 jumper is in low flow setting if
air/gas flow rate is approximately 20 f/s and below (factory default). For liquid or high air/gas
flow rates, the jumper should be in high flow/level position.

Ensure that the pipeline is filled with fluid and at no or minimum flow.

Set trip adjust potentiometer to zero fully counterclockwise (ccw).

Adjust the no-flow pot so that red LED just illuminates. This is a 25-turn pot. If green LED is
on, turn pot counterclockwise (ccw). If the red LED is on, turn the pot clockwise (cw).

Toggle no-flow pot back and forth until the switching point is well defined. Leave red LED illumi-
nated. To ensure best definition/performance, wait approximately 30 seconds between
toggles.

Adjust liquid or gas flow to maximum velocity. Ensure that flow is homogenous, constant
and free of bubbles if a liquid.

Set trip adjust pot to 100 (fully clockwise).

Adjust the full-flow pot so the green LED just illuminates. This is a 25-turn pot. If green LED
is on, turn pot clockwise. If red LED is on, turn the pot counterclockwise.

Toggle full-flow pot back and forth until switching point is well defined. Leave green LED illuminated.
To ensure best definition/performance, wait approximately 30 seconds between toggles.

If the switch is to be used for flow - no flow, set the trip adjust pot to 50 and go to step 14.
A more exact flow rate setting may be achieved by establishing flow at a desired rate with a
separate flow meter and proceeding to step 13, to establish trip point.
Adjust the trip adjust pot to obtain a trip as exhibited by a LED illumination. If a trip on
decreasing flow is desired, set for red LED illumination. If a trip on increasing flow is
desired, set for green LED illumination.
Verify the switch will reset by returning actual product flow to maximum or minimum flow rates.