Troubleshooting - Honeywell EC-FX-NH3 Instruction And Installation Manual

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Troubleshooting

If low-level signals appear to be surfacing occasionally slightly above 4mA,
the internal offset setting may be the issue, especially for differences in
gain settings that have occurred over time.
INTERNAL OFFSET PROCEDURE:
1. Place the EC-FX detector in Cal. Mode.
2. Unplug the sensor from the main board so that it is not electrically
3. For units equipped with an LCD option, unplug the LCD ribbon cable
4. Press the button 8 times quickly without pausing between presses; the
5. After the yellow LED turns off, check the mA output and ensure it is 4mA
The LEDs will give visual indication of several sensor and transmitter
conditions.
If the sensor output is 0 mA: First, verify +24 VDC at the sensor terminal
block (see Figure 8, Note 2).
Second, check voltage between Test (—) and Test (+) (see Figure 8, Note 3).
Voltage should be in the range of 40 mV to 200 mV corresponding to an
actual current flow of 4 mA to 20 mA. If this voltage is 0 mV, the signal has
no path to ground. Check monitoring equipment connections and
configuration.
connected to the EC-FX detector.
from the main board (the same board the sensor is connected to). This
allows the onboard button to function.
yellow LED will blink slowly for 2 min. If the yellow LED doesn't turn on,
the button press timing was too erratic; repeat the 8 button presses again
until the yellow LED blinks slowly.
NOTE: If at any time in step 4 all three LEDs simultaneously blink
slowly, the 4-20mA calibration was initiated accidently because the
button presses were too slow or not consistent. To exit this mode,
press the button for 1 second until the unit reverts back to "run"
mode, or when the LEDs stop blinking and the green LED is on
solid. Place the detector back in factory calibration mode and
repeat step 4.
±0.05mA.
NOTE: If the mA reading is not in range, the 4-20mA output may
need to be re-calibrated. It is not necessary to perform the internal
zero procedure again unless the gain pot was adjusted more than 5
turns.
To re-calibrate the mA loop output, refer to page 21.
Risk of electrical shock.
OPERATOR MANUAL
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