Thermo Scientific Thermo Scientific 3906, Operating Manual

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| Handling and Control
8-4
|
Model 3900 Series Thermo Scientific
Chapter 8

Interrupts power to the heaters and maintain the environmental chamber’s cabinet
temperature at the overtemp safety control point.
If an overtemp condition occurs, the alarm can only be silenced by raising the overtemp
safety thermostat setting. However, the cause of the problem must be determined and
corrected before normal operation under the main temperature controller is resumed.
Figure 8-6
Indicators and Controls
Undertemp Safety Control, Indicator Light and Audible Alarm (Figure 8-6)
The undertemp safety thermostat should be set slightly lower than the operating
temperature of the environmental chamber. In the event of an undertemp condition, the
undertemp safety thermostat will:

Activate the audible alarm and the overtemp indicator light.

Interrupt power to the refrigeration system and maintain the environmental
chamber’s cabinet temperature at the undertemp safety control point.
If an undertemp condition occurs, the alarm can only be silenced by lowering the
undertemp safety thermostat setting. However, the cause of the problem must be
determined and corrected before normal operation under the main temperature controller
is resumed.
Audible Humidity Alarm and Indicator Display (Figure 8-6).
NOTE
The overtemp control is not directly calibrated. The numbers on the dial are for
reference only.
NOTE
In case of overtemperature or power outage the lamps of the light module are
also switched off and the plug controller symbol flashes in the controller.
Humidity
Controller
Humidity Alarm
Temperature Controller
Indicator lights
Cool Indicator Heat Indicator
Overtemp &
Undertemp
Controls
NOTE
The undertemp control is not directly calibrated. The numbers on the dial are
for reference only.