General Monitors S216A, Instruction Manual

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3.6 Main tain ing the X/P In teg -
rity
The Model S216A is rated explosion proof
for Class I, Division 1, Group B, C & D
hazardous locations. Some of the factors
that influence the explosion proof integrity
of the Model S216A housing are:
l
Strength of the enclosure material
l
Thickness of the enclosure walls
l
Flame path between housing and cover
l
Flame path of threaded joints
The acceptable limits for explosion proof
housings being used in Class I hazardous
locations are defined in CSA Standard
C22.2 No.30-M1986.
Anytime the cover of the smart sensor
housing is removed or the cover bolts are
loosened, the flame path between the lid and
the housing is affected. If power is left on
while removing or loosening the cover bolts
on the Model S216A it will be necessary to
de-classify the area first.
When replacing the cover, the gap between
the lid and the housing should be less than
.0015 inch (.038mm). Make sure that the
flame path is clear of dirt and debris before
replacing the cover. This can be verified by
tightening the cover bolts to a torque setting
of 50 inch-pounds or by using a feeler gauge
to ensure the gap between the cover and the
housing is less than .0015 inch (.038mm).
There are four entry holes, one each on the
left and right sides and two on the bottom of
the Model S216A housing. Three of these
holes are dedicated for the sensor, the reset
switch and conduit. Each hole is tapped for
3/4 NPT threads. If a particular entry hole is
not used, it must be plugged during
operation in the field. The factory installs
aluminum housing plugs in the unused entry
holes, except one. A plastic cap plug is
placed into this hole and must be removed
before conduit can be attached to the
housing.
Each Model S216A will have the following
items placed in the remaining entry holes:
l
A sensor, if present (if not, a red
plastic cap plug)
l
A reset switch, if present (if not, an
aluminum housing plug)
l
An aluminum housing plug
The sensor, reset switch and aluminum
housing plug have seven threads. Each of
these components is screwed into the
housing using five to seven turns. If it
becomes necessary to replace one of these
components, the user must use five to seven
turns to ensure the explosion proof integrity
of the housing is maintained.
Model S216A Installation
13