Det-Tronics PIR9400 PointWatch Infrared Hydrocarbon Gas Detector - Manual (Page 22)

20 95-8440 9.3
DISaSSEMBLy aND CLEaNING PROCEDURE
The PointWatch Detector should be inspected periodically
to ensure that its performance is not impaired by fouled
optics or by clogging of the filter or hydrophobic filter.
Inspection and/or periodic maintenance involves three
different areas of the detector.
iMPoRtant
Remove power before disconnecting and
removing the detector for maintenance.
NOTE
It is not necessary to remove the electronics
assembly from the detector base assembly in
order to clean the detector optics.
Filter/Baffle. Perform a visual inspection of the
filter/baffle, checking for a variety of environmental
contaminants including nests of insects, spiders, etc.
Disassemble the PIR
9400 and clean as necessary.
hydrophobic Filter (used on all aluminum and
select stainless steel models). While clogging of the
hydrophobic filter is rare in most installations, the flow of
gas through the filter can be inhibited by an accumulation
of extremely fine particles of airborne contaminants. To
inspect the hydrophobic filter, disassemble the PIR
9400
as described in this section. If the filter appears to be
fouled, replace it. As an alternate to a visual inspection of
the filter, the PointWatch Detector can be tested using the
PointWatch Wind Shield Calibration Bag, available from
Det-Tronics. The bag is slipped over the gas detector
and secured with a Velcro sealing strap. Gas is applied
to the detector through the gas inlet nozzle on the end of
the bag.
iMPoRtant
The hydrophobic filter should be replaced
whenever the mirror assembly and reflector tubes
are cleaned or replaced, or when the filter appears
fouled upon visual inspection.
Optics. Cleaning of the optical surfaces is required only
if an optical fault is indicated ( 1.0 mA current output
signal from the detector, or an “optics fault” message
on the Infiniti U
9500 or FlexVu UD 10 ). This procedure is
most easily accomplished on a bench.
iMPoRtant
If the Model PIR 9400 Detector optics system
is disassembled, calibration is required after
re-assembly.
Required materials: Clean, flat work surface, foam tipped
swabs (no cotton), isopropyl alcohol, screwdriver or hex
wrench.
Caution
The PointWatch Detector contains semiconductor
devices that are susceptible to damage by
electrostatic discharge. An electrostatic charge
can build up on the skin and discharge when
an object is touched. Therefore, use caution
when handling the device, taking care not to
touch electronic components or terminals. If the
electronics assembly is removed, it should be
placed in an anti-static bag or box while stored
or transported. A static safeguarded work area is
highly recommended (if available) for disassembly
and cleaning of the detector.
1. Disassemble the detector as shown in Figure
10 (aluminum) or Figure 11 (stainless steel). For
aluminum models, loosen the two captive screws
on the end of the detector and remove the filter
assemblies. For stainless steel models, loosen the
two captive screws on the end cap, then remove the
baffle and stainless steel collar.
2. Loosen the two captive screws on top of the mirror
assembly (Figure 12 ) and slide the mirror assembly,
hydrophobic filter and reflector tubes away from
the electronics assembly and electronics mounting
cover. See Figure
26 (aluminum model) and Figure
27 (stainless steel model).
3. Disassemble the mirror assembly, reflector tubes
and hydrophobic filter as shown in Figure 26 and
Figure 27 . Do not remove the electronics mounting
cover.
4. Thoroughly douse the interior of the mirror assembly
as well as the foam tipped swab with isopropyl
alcohol. Use the swab to gently cleanse the surfaces
of the reflecting mirrors inside the mirror assembly.
After cleaning with the swab, flush out the mirror
assembly using a liberal amount of isopropyl alcohol.
Tip the mirror assembly with mirror openings
downward to remove accumulated isopropyl alcohol
and particle contaminants. Repeat the alcohol flush
to remove any remaining contaminants. Allow the
mirror assembly to air dry in a dust-free location.