Blodgett SB-10SC Installation Operation & Maintenance page 17

TO CALIBRATE PRESSURE SWITCHES
NOTE: Pressure switches are factory set. Calibration is only required if
pressure switches are replaced or if adjustment is required.
Pressure switch range is from 1 to 15 psi.
Adjust all settings to maximum on high signal adjustment screw on pressure switches.
Adjust in the following sequence:
- High limit pressure switch.
- Override pressure switch.
- Operating pressure switch.
- Turning screw clockwise to increase, counterclockwise to decrease pressure.
- Use relief valve to release pressure from boiler for setting adjustments.
1. HIGH LIMIT PRESSURE SWITCHES
Allow pressure to build until unit shuts off. This should occur at 15 psi. Set the high
signal to switch at 14.5 psi on the gauge and the low signal to 13.0 psi.
2. OVERRIDE PRESSURE SWITCHES
Allow pressure to increase to 13 psi. Set the high signal to switch at 13 psi on the
gauge and the low signal to 11 psi.
3. OPERATING PRESSURE SWITCHES
Set the high signal to switch at 11 psi on the gauge and the low signal to 9 psi.
Release pressure in boiler to below 9 psi. Elements will come on. Once pressure
has reached 11 psi, elements will shut off. Repeat this process several times to
make sure elements come on at 9 psi and shut off at 11 psi.
Once completed, pressure switches have been calibrated.
Should your unit not have the High Limit pressure switch, start procedure at Override
pressure switch.
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