Det-Tronics NTMOS IP66/IP67 H2S Gas Detector - Manual (Page 11)

2.1 95-8670 9
FILTER REPLACEMENT
IMPORTANT
A hydrophobic filter must be installed to maintain
the IP66/IP67 Ingress Protection rating. If a filter is
not installed, the detector assumes an IP53 rating.
The hydrophobic filter provides protection against the
ingress of dust and water, while permitting free flow
of gas to the H
2
S sensor. The filter assembly is field
replaceable. Use the following procedure to replace
the filter if it is determined damaged or contaminated
after a visual inspection, or a failed bump test.
Speed of response will be impeded by the presence of
heavy levels of contamination on the filter, so periodic
inspection is necessary. If the filter is wet, simply let it
dry to restore peak performance. Dry dust can usually
be blown off the filter, but if the filter is contaminated with
oil and dirt, replacement is necessary.
1. Loosen the set-screw that retains the impact guard
with a 1/16” Allen wrench (see Figure 9).
2. Loosen the impact guard by rotating it counter
clock-wise.
3. Remove the filter assembly.
4. Inspect the O-ring that seals the filter assembly to
the housing and also the O-ring that seals the filter
assembly to the impact guard. Make sure that the
O-rings are clean, properly seated and in good
condition. Replace the O-rings (p/n 011364-001) if
they are damaged.
5. Install the replacement filter in the impact guard so
that the reinforcing ribs are facing toward the sensing
element, as illustrated in Figure 8.
6. Install the impact guard on the NTMOS Detector, by
rotating it clockwise until firmly tight. Use care when
tightening the setscrew to prevent damage to the
threads on the impact guard.
See the Ordering Information section of this manual for
replacement parts and accessories.
Figure 9—NTMOS Detector Disassembly
CORRECT INCORRECT
SET-SCREW
(Do not overtighten
when reassembling)
O-RINGS
NTMOS HOUSING
HYDROPHOBIC
FILTER
IMPACT GUARD
SENSING ELEMENT
A2568
Figure 8—Hydrophobic Filter Placement