INSTALLATION & OPERATING DATA
9 MAINTENANCE
continued
9.4
Display
In addition to displaying the gas type and actual gas readings,
the display can indicate the status of the instrument.
Head Removal
If a gas sensing head is removed, the display will indicate this by
showing .
The output current will fall to about 1.5 mA for 2-wire systems. On
non-2-wire systems the output signal will remain fixed for
15 seconds and then down scale to about 3 mA.
If the head is replaced, then normal operation is resumed.
Underrange
If for any reason the signal from the head drops below the
normal baseline level (head failure for example) the display will
indicate . Once the underrange condition is cleared, then
the display will return to normal.
Overrange
If the gas sensing head ‘sees’ a gas concentration of 1% or more
above its full scale output, the display will indicate .
This mode may only be cleared by cycling the power.
9.5
Remove Gas Sensing Modules (TX6373.84)
Insert a bar into one of the radial holes in the gas inlet bush
(take care not to damage the internal filter) and unscrew the gas
inlet bush. Remove the filter from the gas inlet bush. Clean or
replace the filter as necessary. Fit a new or cleaned filter to the gas
inlet bush. Using a spanner, remove the sensor retaining nut from
the remote housing. Remove the gas sensing module from the
remote housing. Fit a new gas sensing module to the remote
housing, refit the sensor retaining nut and tighten. Refit the gas
inlet bush and tighten using a bar inserted into one of the radial
holes, taking care not to damage the filter.
9.6
Annual Safety Check
The main transmitter itself will not normally require maintenance or
calibration but it is advisable to return it to the Trolex Product
Support Department for an annual safety check.
9.7
Damaged Sensors
A Sensor that has been dropped or damaged in any way should
be taken out of service immediately for inspection, repair and
re-calibration.
9.8
Record Keeping
Institute a regular calibration and maintenance procedure and
keep a record.
Incorrect use of the Sensor or inadequate maintenance may
not necessarily be self evident in the Sensor and consequently
it must be regularly checked and maintained.
18/25
ISSUE N 06/15
