2.4 Power Connection
See the serial tag on the side of the unit for electrical speci-
fications, or refer to the electrical schematics at the end of this
manual.
Connect the incubator to a grounded, dedicated
circuit. The power cord connector is the mains dis-
connect device for the incubator. Position the
incubator so the unit can be easily disconnected.
For Model 3920, plug the provided 10 ft. power cord with
the NEMA 14-20 plug into the grounded dedicated electrical cir-
cuit.
2.5 Start-Up
Preset the controls as follows:
Overtemp Safety Thermostat . . . . . . . . . . . . . Fully Clockwise
Undertemp Safety Thermostat . . . . . . Fully Counterclockwise
Main Power Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ON
Temperature Controller . . . . . . . . . . . . . . . . . .Desired Setpoint
Door Heater . . . . . . . . . . . . . . . . . . . . . . . . . .40% (factory set)
Turn the Main Power switch on. The Power indicator and
Heat indicator will light. Turn the Refrigeration switch on and
the indicator will light.
The compressor and refrigeration lights will not
come on if the chamber temperature is within
+4°C of the temperature controller.
2.6 Setting the Overtemp Safety Thermostat
Allow the chamber temperature and humidity to stabilize
then set the overtemp safety thermostat as follows:
1. Turn the overtemp control knob slowly counterclockwise
until the audible alarm sounds and the overtemp indicator
lights.
2. Turn the overtemp control knob clockwise at least 2
degrees. The alarm should be silenced and the overtemp
indicator light should go out. The overtemp safety ther-
mostat is now set a few degrees above the control tem-
perature setpoint. When the chamber temperature rises to
the overtemp control point, the alarm system will acti-
vate, power to the heaters will shut off, and the chamber
temperature will be maintained at the overtemp control
point.
When an overtemp condition occurs, the cause must be
determined and corrected before normal operation under the
main temperature controller can be resumed.
Note:
When the chamber temperature control setpoint is
changed, the overtemp safety thermostat must be reset to accom-
modate the change.
Note:
The overtemp control is not directly calibrated. The num-
bers on the dial are for reference only.
2.7 Setting the Undertemp Safety Thermostat
Allow the chamber temperature and humidity to stabilize,
then set the undertemp safety thermostat as follows:
1. Turn the undertemp control knob slowly clockwise until
the audible alarm sounds and the undertemp indicator
lights.
2. Turn the undertemp control knob counterclockwise at
least 2 degrees on the scale. The alarm should be silenced
and the undertemp indicator light should go out.
The undertemp safety thermostat is now set a few degrees
below the control temperature setpoint. When the chamber tem-
perature drops to the undertemp control point, the alarm system
will activate, power to the compressor will shut off, and the
chamber temperature will be maintained at the undertemp con-
trol point.
When an undertemp condition occurs, the cause must be
determined and corrected before normal operation under the
main temperature controller can be resumed.
Note:
When the chamber temperature control setpoint is
changed, the undertemp safety thermostat must be reset to
accommodate the change.
Note:
The undertemp control is not directly calibrated. The num-
bers on the dial are for reference only.
2.8 Preparing the (Optional) CoBex Recorder
a. Installing the Battery
The seven-day circular chart recorder is located on the front
of the incubator cabinet and is protected by a glass door.
To prepare the recorder for operation, open the glass door
and snap the connector onto the 9-volt battery (Figure 2-4). If
the unit is operating, the green LED lights steady. If the unit is
not turned on, the LED blinks.
2 - 2
Environmental Chamber ________________________________________________________________Installation and Set-Up
