ENMET ISA-44-RALE-OD - Manual (Page 14)

ENMET Corporation ISA-44RALE-OD/ISA-44RAHE-OD/ISA-44E-OD
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3.0 Installation and Warm-up 3.0 Installation and Warm-up
W ARNING : Area must be declassified during installation.
When installing the ISA-44RALE-OD/ISA-44E-OD, remember that the instrument is not explosion proof when the
instrument or sensor enclosure covers are removed. Make certain that the surrounding atmosphere has been declassified
when you install the ISA-44RALE-OD/ISA-44E-OD. Use a portable gas detector or flush the area with clean, fresh air.
N OTE : There is no on/off switch for the ISA-44RALE-OD/ISA-44E-OD. The instrument is designed to operate
continuously 24 hours a day.
When choosing a location for the instrument, several things must be taken into consideration. The unit should be in such
a position that appropriate personnel are notified when the unit goes into alarm. The ISA-44RALE-OD should be located
so that the respiratory air reaches the sensors before it reaches the workers. In addition, the sampling point of the sample
head assembly should not be located at a low spot in the compressed air line; water often condenses in compressed air
lines and drains to low points in the line (ISA-44RALE-OD only). Water will damage the regulators and sensors of the
ISA-44RALE-OD; the only water that should contact the sample head assembly is in the humidifier (bubbler). Finally,
the instrument requires that air pass over the MOS sensor at all times.
C AUTION : Since the ISA-44RALE-OD operates 24 hours a day, if the air supply to the MOS sensor is cut off, it will
overheat and/or become highly inaccurate.
3.1 Sensor Location for ISA-44E-OD
Gases have different densities. Some are heavier than air and concentrate at the bottom of a space. Some are lighter than
air and gather at the top. Consider the density of the gas you want the sensor to detect when you install the sensor.
Table 2: Sensor Location
Heavier than Air Sensor Location
bottle liquefied petroleum
propane
butane
gasoline
trichloreothylene
vaporized hydrocarbons
Interior wall, 18 - 24" from the floor.
NOT directly above or beside gas ovens, heaters, windows, vents,
doorways.
Lighter than Air Sensor Location
natural gas Locate near ceiling.
NOT directly above appliances where it is subject to direct exposure to
heat or steam.
Same Density as Air Sensor Location
carbon monoxide Locate 4 - 6 feet above the floor.
NOT in direct air currents of windows, doors or vents.
If you have a problem involving the locations of a unit, please contact your distributor or ENMET personnel. A
technician will analyze the problem and recommend a location.
The ISA-44RALE-OD/ISA-44E-OD operates on 110 V AC . (220v optional)
N OTE : If the ISA-44RALE-OD/ISA-44E-OD is ordered with a horn from the factory, the unit will include a third
position on the Purge/Operate/Horn-off switch (HORN-OFF) to silence the horn during testing or calibration. If
the user installs his own horn, the switch on the instrument has only two positions (PURGE/OPERATE
[optional]), so the user must install a separate switch to silence the horn during testing.