TROUBLESHOOTING
8-4
8.2 Lamp Troubleshooting Details
Cold Lamp Startup
The UV (ultraviolet) lamp is made of a glass envelope and a
UV window on one end of the envelope. The lamp is filled with
low-pressure gases. To turn on the lamp, a high-voltage
electric field is applied from the outside of the glass envelope.
The molecules inside the lamp are ionized and produce a glow
discharge effect to generate the UV light. Because this UV
lamp does not have an electrode inside the glass envelope, it
requires a small amount of ions inside the lamp to initiate the
glow discharge process.
If the UV lamp has not been used for a long period of time
(longer than one month), the ion count inside the lamp
becomes low. It may be slightly harder to turn on the UV lamp
for the first time. If such a condition occurs, an error message
“Lamp” appears in the monitor display during the power-on
sequence. This phenomenon is more significant in 0.25
"
UV
lamps used in the AreaRAE Steel, because of the relatively
small lamp size.
To solve this problem, turn the monitor on and off a few times,
and the lamp should turn on. Gently shaking the monitor also
helps to initiate the glow discharge process. After the UV lamp
is turned on for the first time, it should be easier to turn on the
UV lamp the next time.
AreaRAEs feature a built-in sensing mechanism to monitor the
status of the UV lamp. If the UV lamp is not on, the error
message “Lamp” is displayed. It is possible that the UV lamp is
actually on when the lamp error message appears. When the
UV lamp becomes old, is changed, or the configuration file
inside the AreaRAE monitor has been totally overwritten, the
threshold level to determine lamp failure may be wrong and
cause a false alarm. To eliminate this possibility, apply some
VOC sense by putting a permanent marker (such as a Magic
Marker) close to the inlet of the AreaRAE and see if the VOC
raw count goes up.