Sensor Handling In Hazardous Areas; Removing The Sensor From The Stack; Opening The Sensor Enclosure In A Hazardous Area; Cleaning The Sensor - Pentair Goyen Mecair FFD Installation And Operation Manual

8.3 SENSOR HANDLING IN HAZARDOUS AREAS

8.3.1 Removing the Sensor from the Stack

WARNING! – NON-ISOLATED EQUIPMENT
Do NOT electrically disconnect the enclosure from the stack (i.e. break the ground/earth connection)
in the presence of hazardous dusts. Circulating currents in the ground system could create an ignition
hazard.
To disconnect the probe safely, remove the sensor from the stack, then disconnect the sensor from the
power source or control unit by unplugging the connection wire at the power source (in the designated
Safe Area).
Only once the sensor has been isolated from the power source, is it safe to disconnect the earth
connection between sensor enclosure and stack wall.
1. Switch OFF power to the sensor.
2. Remove the sensor in the usual way, ensuring that the grounding strap (earth wire) remains connected.
3. With the power OFF and the grounding strap in position, disconnect the sensor from the cable as follows:
a) Open the enclosure (see below for instructions).
b) Disconnect the cable (secure the bare wires in a safe dust-free manner).
c) Disconnect the grounding strap.

8.3.2 Opening the Sensor Enclosure in a Hazardous Area

WARNING! – EXPLOSION OR COMBUSTION RISK
The equipment may be opened only when it is de-energized or the area has been designated as 'safe'
at that time.
1. Switch OFF and isolate mains power.
2. Open the enclosure by removing the lid.
3. Ensure no dust has settled in enclosure before replacing and securing the lid.

8.4 CLEANING THE SENSOR

WARNING!
POTENTIAL ELECTROSTATIC CHARGING HAZARD
Refer to the Special Conditions of Safe Use on pages 6 and 7 for details.
CAUTION!
(1) Do not allow moisture to penetrate the unit.
(2) Do not use solvents or oil-based cleaners to remove contamination or accumulations of dirt as these can
damage the surfaces, and the seals and insulator on the sensor.
The FFD is designed to require minimal servicing; however, the nature of many processes is such that a large build-up
of particulate may develop on the sensor rod. This build-up will often have no effect on the performance of the instrument,
but it is recommended that the build-up is periodically removed. The grounding strap should be sufficiently long to remove
the sensor and place it on the ground or platform without disconnecting.
Should the probe rod require cleaning, this can be performed by removing the sensor from the duct and thoroughly
cleaning the entire rod. Pay particular attention to the cleanliness of the insulator.
Wire wool or brushes may be used for cleaning sensor metal parts only, and for sticky or stubborn deposits a fast-drying
cleaning agent – note that this must have been approved for use in the particular type of hazardous zone!
Always refer to the Safety Information at the start of this section before commencing cleaning procedures.
NOTES:
(i) If using wire wool, clean the sensor parts using a rotational cleaning action to prevent scratches, particularly along the
sensor probe.
(ii) Ensure that the probe rod is thoroughly dried before refitting the sensor to the ductwork.
1. Remove the sensor unit from the ductwork (see section 8.3 above for instructions relating to sensor removal in
hazardous zones).
2. Thoroughly clean the probe rod and insulator as described above.
22 INSTALLATION AND OPERATION MANUAL – OWNER'S RECORD FFD MANUAL – FILTER FAILURE DETECTOR