Detcon FP-524D INSTRUCTION MANUAL - Manual (Page 32)

Model FP-524D
FP-524D Instruction Manual Rev. 1.4 Page 28 of 39
4. Service and Maintenance
Calibration Frequency
In most applications, quarterly to biannual zero and span calibration intervals will assure reliable detection.
However, industrial environments differ. Upon initial installation and commissioning, close frequency tests
should be performed, weekly to monthly. Test results should be recorded and reviewed to determine a suitable
calibration interval.
Visual Inspection
The Sensor should be inspected annually. Inspect for signs of corrosion, pitting, and water damage. During
visual inspection, the Splash Guard should be inspected to insure that it is not blocked. Examine the porous
316SS flame arrestor within the sensor’s bottom housing for signs of physical blockage or severe corrosion.
Also, inspect inside the Junction Box for signs of water accumulation or terminal block corrosion.
Condensation Prevention Packet
A moisture condensation packet should be installed in every explosion proof junction box. The moisture
condensation prevention packet will prevent the internal volume of the J-Box from condensing and
accumulating moisture due to day-night humidity changes. This packet provides a critical function and should
be replaced annually. Detcon’s PN is 960-202200-000.
Replacement of Combustible Gas Sensor
NOTE: It is necessary to remove power while changing the combustible gas sensor in order to
maintain area classification while the junction box cover is removed. Proper “Hot Permits”
may apply.
a) Remove the junction box cover and remove the Transmitter Module from the Connector PCB.
b) Unthread the lower half of the sensor housing. The lower housing includes two recessed holes for a
spanner wrench if needed.
c) Gently pull on the combustible gas cell to unplug it from the upper housing.
d) Orient the new plug-in sensor so that it matches with the female connector pins, and plug into the
upper housing.
e) Thread the lower housing back into the upper housing and tighten using a spanner wrench.
f)
Perform “Set Bridge Voltage” (Section 3.5.5) to match the new combustible gas sensor with the
Transmitter Module.
g) Perform a successful AutoZero and AutoSpan to match the new combustible gas sensor with the
Transmitter Module (Section 3.4).
Replacement of Transmitter Module
a) Remove the junction box cover and unplug the Transmitter Module from the Connector PCB.
NOTE: It is necessary to remove power to the junction box while changing the transmitter
module in order to maintain area classification.
b) Plug the new Transmitter Module into the connector PCB, and reinstall the junction box cover.
c) Perform Set Bridge Voltage and Set AutoSpan Level and then perform a successful AutoZero and AutoSpan
before placing sensor assembly into operation.