Ultima MOS-5 Detector
16
Anytime the cover of the Ultima MOS-5 Intelligent Sensor housing is removed or the cover bolts
are loosened, the flame path between the lid and the housing is affected. If power is to be left
on while removing the cover or loosening the cover bolts on the Ultima MOS-5 Intelligent
Sensor, the area must be declassified.
When replacing the cover, the gap between the lid and the housing should be less than 0.0015
inch (0.038 mm). 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
0.0015 inch (0.038 mm).
There are four entry holes, one each on the left and right sides, and two on the bottom of the
Ultima MOS-5 Intelligent Sensor housing. These holes are dedicated for the sensor, the reset
switch, and conduit. Each hole is tapped for ¾” NPT threads. If a particular entry hole is not
used, it must be plugged during operation in the field. The factory installs plugs in the unused
entry holes, except one. A red plastic cap is placed into the remaining hole and must be
removed before conduit can be attached to the housing.
The Ultima MOS-5 Intelligent Sensor will have the following items placed in the three remaining
entry holes, at the factory:
•
A sensor, if present (otherwise a red plastic cap)
•
A reset switch, if present (otherwise an aluminum housing plug – optional)
•
An aluminum housing plug
The sensor, reset switch, and aluminum - housing plug have 7 threads. Each of these
components is screwed into the housing using 5 to 7 turns. If any of these parts must be
replaced, apply 5 to 7 turns upon replacing the component to ensure the explosion proof
integrity of the device is maintained.
