023-064X Technical Manual
70-PHW-1018-R3.2 MTA 8.5 023-064X Refrigerant Leak Detector Manual.docx
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4
Operation
The power supplied should be between 17 to 28 vac or between 21 to 30 vdc. If the power is too high
or too low the sensor will not work properly.
Each time the unit is powered on with proper power, the relay is disabled and the analog outputs stay at
0 during the warm up period. This is to allow time for the sensor to warm up and to avoid false alarm
due to high readings of the cold sensor. The warm up timer may be cancel by pressing any arrow. The
reading may take a few more minutes to stabilize as the sensor may need more warm-up time if it was
not powered for many days. The warm up time can be changed to up to 255 sec with the 52 W/U user
setting. After power-up it will take 48 hours for maximum accuracy to be obtained, although accuracy is
very good after an hour.
When the gas concentration is higher than the threshold set by AL1 for the time A1Del the relay is
energized. The display will display 1 at the bottom left of the display. The relay will de-energized A1Off
seconds after the gas concentration drops below the threshold.
AL1 is for relay settings, AL2 is for alarm 2 settings and AL3 is for alarm 3 and buzzer settings.
See section 3.2
The buzzer may sound when alarm 3 activates. To silence the buzzer, press any arrow.
See section 3.3
for override and test commands.
5
Calibration
Procedure specifically for refrigerant sensors:
1. Use certified bottled calibration gas mixed with air only, not nitrogen. Ensure that sensors are
powered on for a minimum of the break-in period for the sensor. For these sensor types, this is two
days.
2. Inject bottled span gas and wait until the gas reading stops going up. The span gas used must be
within the range of sensor’s scale.
Use a flow rate of 0.1 LPM to 0.5 LPM. The gas fitting to sensor
should have a small outlet hole. If not, the pressure will increase and distort the reading (high).
3. Adjust the blue potentiometer on the module to set the sensor reading displayed to that of the bottle
mix. Do not change the factory calibration constants in calibration mode as above.
4. Remove span gas mix and supply air. Sensor will return to zero.
5. If sensor does not return to zero, it needs replacement
Mode conveniently you can order a new replacement sensor module factory calibrated
See section 1.3