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MAN0889_Issue 3_03/13
The Searchline Excel Cross-Duct maintenance should include regular cleaning of the Transmitter and Receiver
unit windows and the Heated Reflector Panel, re-zero of the Cross-Duct unit and functional test using Test
Filters (2104N3000).
Note: The objective is to keep the windows clean. The rate of build up of contamination depends on local site
conditions. It is recommended that the installation is closely monitored during the first few weeks of
operation to establish how frequently cleaning will be required.
Depending on the local regulations and site conditions, cleaning and functional testing of the gas detector
can be carried as described in the following sub-sections. The gas detector should remain powered during
these procedures.
Caution: Searchline Excel Cross-Duct does not contain any user serviceable parts. Do not open or
disassemble the Transmitter and Receiver unit (other than as instructed), or the Heated
Reflector Panel. The warranty of units which have been opened is invalidated.
Note: THE INFRARED BEAM IS INVISIBLE AND EYE SAFE.
4.1 Inspection and Cleaning
Caution: Do not use solvents or abrasives on the Searchline Excel Cross-Duct units.
(1) Inspect the Searchline Excel Cross-Duct units, junction boxes and cabling for signs of physical
damage.
(2) Using the SHC1 Handheld Interrogator inhibit the Searchline Excel Cross-Duct signal output.
Since the signal output may vary during cleaning, due to the optical path being disturbed, it is important
to inhibit the analogue output. The quickest way to inhibit the Excel output is to select DISPLAY from the
Calibrate menu.
(3) To access the Transmitter and Receiver windows, and the beamsplitter, remove the top cover from the
mounting block.
The cover is retained by 3 x M4 captive bolts, and a chain attaches the lid to the mounting block when
opened. There are no electrical hazards inside the mounting block and a hot work permit is NOT
required.
(4) Clean any dust or dirt from the Transmitter and Receiver windows and the beamsplitter using soapy water
or window cleaner and a soft cloth.
(5) Replace the top cover of the mounting block.
(6) Loosen the fixings which secure the Heated Reflector Panel and remove it from the duct wall.
(7) Clean any dust or dirt from the Heated Reflector Panel using soapy water or window cleaner and a soft
cloth.
(8) Replace the Reflector Panel on the duct wall and tighten fixings.
(9) Using the SHC1 Handheld Interrogator release the Searchline Excel signal output.
The output can be released by pressing ESC followed by
(10) Re-zero the system (see section 4.2).
To reduce the need for cleaning, it is possible to connect a supply of compressed air to the Air Shield port on
the mounting block (see diagram in section 4.3). The air shield port is the one closest to the duct. By flowing
clean air into the mounting block (which then moves out into the duct), the build up of contamination inside
the mounting block will be reduced. It is essential that this air supply is oil and dirt free. Precautions such as
a filter and a liquid trap should be installed in the air-line.
4. Maintenance
35
Searchline Excel Cross-Duct Technical Handbook
on the keyboard.
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