Detcon FP-624D-HT - Manual (Page 37)

Model FP-624D-HT
FP-624D-HT Instruction Manual Rev. 1.1 Page 33 of 44
5. Service and Maintenance
Calibration Frequency
In most applications, monthly to quarterly 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. If, after 180 days, an AutoSpan calibration is not performed, the sensor will generate an
AutoSpan fault.
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 High Temperature combustible gas sensor
NOTE: It is necessary to remove power while changing the High Temperature 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 High Temperature sensor housing.
c) Disconnect wires from terminal board.
d) Replace High Temperature sensor housing, applying anti-seize compound to threads, re-attach wires to
terminal board.
e) Perform “Set Bridge Voltage” (Section 3.5.5) to match the new High Temperature combustible gas
sensor with the Transmitter Module.
f) Perform a successful AutoZero and AutoSpan to match the new High Temperature combustible gas
sensor with the Transmitter Module (Section 3.4).
Replacement of Transmitter Module
a) Remove the junction box cover and remove 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 Range, Set Heater Power, and Set AutoSpan Level then perform a successful AutoSpan
before placing sensor assembly into operation.