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

9.3 SENSOR HANDLING IN HAZARDOUS AREAS

9.3.1 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 control unit (in the designated
Safe Area).
Only once the sensor has been isolated from the power source/control unit, is it safe to disconnect the
earth connection between sensor enclosure and stack wall.
1. Switch OFF and disconnect mains power.
2. Remove the sensor in the usual way, ensuring that the ground strap or 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 section 9.3.2 below for information).
b) Disconnect the cable (secure the bare wires in a safe dust-free manner).
c) Disconnect the grounding strap.

9.3.2 Opening the Sensor Enclosure

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 disconnect mains power.
2. Open the enclosure by removing the lid. Carry out any necessary actions.
3. Ensure that no dust has settled in the enclosure before replacing the lid.

9.4 CLEANING PROCEDURES

WARNING!
POTENTIAL ELECTROSTATIC CHARGING HAZARD
Refer to the Special Conditions of Safe Use (section 4.2 on page 8).
CAUTION!
(1) Do not allow moisture to penetrate the units.
(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.

9.4.1 Cleaning the Sensor

The FFA 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.
Cleaning may be performed using wire wool, for sticky or stubborn deposits a cleaning agent may be used
provided this has been assessed as being acceptable for use in hazardous zones! If so, use a fast-drying solvent
cleaner (not water!).
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 Sensor Handling in Hazardous Areas above).
2. Thoroughly clean the probe rod and insulator as described above.
3. Clean off any excessive build-up from the sensor enclosure using a stiff brush or a damp cloth (do not use a dry
cloth!).
INSTALLATION AND OPERATION MANUAL – OWNER'S RECORD FFA MANUAL – FILTER FAILURE ALARM 29