SENSOR AND PUMP MAINTENANCE
6-4
6.2 PID Sensor Maintenance
This section only applies to IAQRAE monitors that are
equipped with a PID sensor. During the course of normal
operation, a film of gas vapor may build up inside the PID
sensor module and the UV lamp. The rate at which the film
develops depends on the type and concentration of the vapors
being sampled.
The PID lamp/sensor is self-contained and not designed to be
cleaned manually. If the PID has poor sensitivity, the sensor
should either be replaced or cleaned using the automatic self-
cleaning function. Turn the unit on in manual operation mode,
place it in a clean environment (<2 ppm VOC reading) and set
the duty cycle to the lowest value (50%) to allow the maximum
self-cleaning.
IAQRAE has a built-in sensing mechanism to monitor the
status of the UV lamp. If the UV lamp is not on, the “Lamp”
error message will appear. To resolve this problem, it may help
to turn the monitor on and off a few times. It is possible the UV
lamp is actually on when the “Lamp” error message appears.
When the UV lamp ages, changes, or the configuration file
inside the IAQRAE has been completely overwritten, the
threshold level to determine lamp failure may be wrong and
cause a false alarm. To eliminate such possibilities, apply
some VOC source by putting a felt-tipped marker close to the
inlet of the IAQRAE and see if the VOC raw count increases. If
the UV lamp is on while the error message persists, then the
lamp threshold must be reduced to below the actual lamp
current reading. (See Section 7.1 Diagnostic Mode - Show PID
Lamp Parameters)
