What do the jumpers on the right of the circuit board do on the Model 231?

The top jumper for BAR/PSI allows you to select engineering units in Bar ranges or PSI.

The REV/NORM jumper: When in REV (reverse) mode, the output increases when the differential pressure decreases and decreases as pressure increases. In NORM (normal): When in Normal mode, output increases as pressure increases and decreases as pressure decreases.

SLOW/FAST: When Slow mode is selected, 5-second averaging is provided for surge damping.

Bi-DIR/UNI-DIR: Select UNI-Directional or BI-Directional mode. Unidirectional mode measures from 0 to full scale differential pressure. Bidirectional mode measures pressure from minus 1/2 of full scale to plus 1/2 of full scale differential pressure. Output will read 1/2 full scale when differential pressure is zero.

SWAP/NORM: Jumper selectable Port Swap feature eliminates costly re-plumbing when incorrectly installed or replaced. Go from NORMAL to SWAP and the jumper makes the "HI" Port "LO" and the "LO" port "HI"