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15
CHAPTER 5 MAINTENANCE
Routine Maintenance
The UVU-140-A & UVU-140-AR fire detectors require no periodic calibration. To maintain maximum sensitivity,
the viewing window and reflector should be cleaned on a routine basis depending on the type and amount of
contaminants in the area.
The rubber o-ring on the detector housing is used to ensure the detector is watertight. The housing should be
opened periodically and the o-ring inspected for breaks, cracks or dryness. To test the o-ring, remove it from the
detector housing and stretch it slightly. If cracks are visible, the o-ring should be replaced. If it feels dry to the
touch, a thin coating of lubricant should be applied. When re-installing the o-ring, be sure that it is properly seated
in the groove on the housing.
The o-ring must be properly installed and in good condition to prevent water from entering the detector and
causing failure. The life expectancy of rubber o-rings varies, depending on the type and amount of contaminants
present in the area. The person who maintains the system must rely on experience and common sense to
determine how frequently the rings should be inspected. A coating of lubricant should also be applied to the
enclosure threads before reassembling the detector to help prevent moisture from entering.
CAUTION:
The o-ring should be lubricated with polyalphaolefin grease, such as GRS-450 made by CPI
Engineering. Silicone based lubricants should never be used if catalytic type combustible gas sensors
are being used in conjunction with the UV detectors, since silicone lubricant on or near the
combustible gas sensor will cause permanent damage to the sensing element.
Troubleshooting
The automatic vi (visual integrity) feature continuously checks the detector for correct response. If a problem is
detected, Table 4 shows the current output levels for various situations.
Cleaning Viewing Window and Reflector
When cleaning the viewing window and reflector use a clean, lint free cloth and the cleaning solution provided
with the detector. Use only recommended cleaning solutions, as some cleaners can leave a residue that can block
UV radiation.
Repositioning vi Adjustment Allen Screw
The UV sensor module has an adjustable Allen Screw. This adjustable Allen Screw controls the amount of light
released from the vi source during visual integrity testing. To increase the amount of UV light released, turn the
Allen Screw counter-clockwise, this will open the orifice and allow more light to pass through. An ideal setting
with a clean lens and reflector would yield an analog output of 12mA during the manual vi test, which represents
an excellent response level when performing a manual vi check.