INSTRUMENTATION
Power Signal
All dryers are equipped with an ON-OFF switch located
on the front panel. A white light signals when power is
on.
System Operation Monitor
A System Operation Monitor measures and displays
critical air and refrigerant temperatures, signals operat-
ing conditions which may affect dryer performance, and
enables panel adjustment of the automatic drain valve.
There is also a light to indicate the need for routine
service.
The monitor consists of (refer to Figure 4):
• indicating lights
• alphanumeric display
• controls (push buttons) that provide access to
critical air and refrigerant temperatures
• schematic with lights that correspond to the
locations of the temperature sensors in the system
• drain valve controls
• temperature sensor probes
1-4
Indicating lights
The System Operation Monitor has four indicating
lights: NORMAL OPERATION, CHECK OPERAT-
ING CONDITIONS, SERVICE DUE and SYSTEM
ALARM. Table 3 provides instructions for using the in-
dicating lights to monitor dryer operation .
NORMAL OPERATION—The green NORMAL OP-
ERATION indicator will light when the temperature in-
side the evaporator (chiller) is normal.
CHECK OPERATING CONDITIONS —The red
CHECK OPERATING CONDITIONS indicator will
light when the temperature inside the evaporator is too
high.
SERVICE DUE—The yellow SERVICE DUE indica-
tor will light under two conditions: as a reminder to per-
form routine maintenance after 4,500 hours of dryer
service (approximately six months) and when a tem-
perature sensor probe fails.
SYSTEM ALARM—The red SYSTEM ALARM indi-
cator signals air system or dryer operating conditions
that may affect dew point performance or cause damage
to the dryer.
Temperature SCAN/SEEK push button
The SCAN/SEEK push button on the System Operation
Monitor provides a readout on the alphanumeric display
of the following temperatures:
• inlet air
Figure 4.
System Operation Monitor
DXR Series Dryers (Bulletin 553)