MAINTENANCE
7-9
7.4 PID Lamp Care
The UV lamp is made of a glass envelope and a UV window
on one end of the envelope. The inside of 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 to generate the UV light. Because
this UV lamp does not have an electrode inside the glass
envelope, it requires only 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
(> 1 month), it may be slightly harder to turn on. If such a
condition occurs, an error message “Lamp” will appear in
the monitor display during the power on sequence. This
phenomenon is more significant in 0.25” UV lamps used in
MultiRAE Plus products, because of the relatively small
lamp size.
To solve this problem, simply turn on and off the monitor a
few times and the lamp should turn on. Gently shaking the
monitor will also help 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 next time.