Span Calibration - Honeywell EC-FX-NH3 Instruction And Installation Manual

The EC-FX-NH3 detector is factory calibrated but it must also be
calibrated at start-up. The sensor performs best when calibrated in the
environment in which it will be used. Using calibration gas other than the
recommended full scale will affect the stated accuracy. One pot on the
preamp is used for Span calibration (see Figure 4, Note 1). There is no
zero pot as the pre-amp is factory zeroed and should not require any
further adjustment.
Calibration Kits are available from Honeywell Analytics. See page 32 for kit
part numbers and descriptions. Calibration gas must be ordered separately;
refer to the Refrigeration Price Book for ranges and prices.

Span Calibration

The unit is factory calibrated but must be spanned at initial installation. Do
not adjust the span pot without certified calibration gas.
For span calibration, follow this procedure:
Start:
1. With meter set to mVDC, place leads on Test (+) and Test (-).
2. Make sure signal is resting at 4.0 mV ±5 mV. If the sensor is not
outputting 4.0 mA, see Troubleshooting on page 27. In some cases,
opening doors changes the temperature, environment, and ambient
air flow to the sensor which impacts its stability during this
procedure.
3. Place the unit in calibration mode by pressing the button for 3
seconds until the green LED flashes slowly or, for units equipped
with the LCD option, initiate the calibration mode using the front
panel push buttons.
NOTE: After 10 minutes, the unit will automatically revert to
run mode.
NOTE: Keep hands away from the sensor in order for a
stable output to be achieved, as moisture and air flow can
affect stability.
4. Place the EC-FX calibration adaptor (EC-FX-CA) on the sensor and
ensure that it is fully-seated and aligned. Gas with full-scale span gas
NH mixed in air @ 0.3 L/min until the 4-20 mA output signal rise
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