Honeywell 705 Series, Calibration Handbook, Page: 59 / 164

Calibration Handbook
59 Manning EC-F3-O2
EC-F3-O2 Calibration Procedure
General Information
The Manning EC-F3 oxygen sensor comes factory calibrated but may require a span adjustment upon
installation to compensate for local altitude and barometric pressure conditions.
Effects of Barometric Pressure on Oxygen
The output of the Manning EC-F3-O2 sensor is affected by changes in barometric pressure. If a unit is calibrated
at a barometric pressure of 29.00 inches Hg in clean air to output 20.9 % O2, and the barometric pressure
changes to 28.00 inches Hg, the output will indicate 20.2 % O2. Because of this, the installer should always
perform a nominal calibration as described below when the unit is started up. After the nominal calibration is
performed, the output will be expected to vary slightly with barometric pressure.
Nominal Calibration: After the unit is installed and has been powered up for a minimum of 8 hours, a nominal
calibration will be achieved by the following method.
s Be sure the unit is in clean air with the area well ventilated.
s The sensor should indicate a concentration of approximately 20.9 %, which is the normal concentration
of oxygen in clean air. This will vary depending on elevation and barometric pressure.
s Adjust the span pot until the sensor output indicates a concentration of 20.9 %. For the following ranges,
the test signals should be:
Range 0-25%
0.0% = 4 mA or 40 mV (TP1-TP2)
25% = 20 mA or 200 mV (TP1-TP2)
Range 15-25%
15% = 4 mA or 40 mV (TP1-TP2)
25% = 20 mA or 200 mV (TP1-TP2)
Zero Calibration
DO NOT adjust the zero pot without certified calibration gas. If zero adjustment is required, the following
procedure will zero the unit.
s
Apply zero gas at 1.0 L/min (zero gas must be in nitrogen).
s
After zero gas has been on sensor for two minutes, adjust the zero pot until the correct output is achieved.
Span Calibration
Span calibration can be achieved by performing the nominal calibration described at the beginning of this
section or by using calibration gas as follows:
s Perform zero adjustment before spanning.
s
Apply span gas at 1.0 L/min (span gas must be in nitrogen).
s
After span gas has been on sensor for two minutes, adjust the span pot until the correct output is achieved.