Models 3940 and 3949 ________________________________________________________________Installation and Set-Up
2.5 Power Connection
The electrical junction box is located on the rear top sec-
tion of the incubator. With the junction box switch OFF, con-
nect the incubator to an adequate power source. See the electri-
cal data plate mounted on the side of the unit for exact electri-
cal specifications.
2.6 Start-Up Procedure
When the humidification system is operational, the incuba-
tor may be started. Preset the controls as follows:
Overtemp Safety Thermostat . . . . . . . . . . . . . Fully Clockwise
Undertemp Safety Thermostat . . . . . . Fully Counterclockwise
Main Power Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ON
Humidity Controller . . . . . . . . . . . . . . . . . . . .Desired Setpoint
Temperature Controller . . . . . . . . . . . . . . . . . .Desired Setpoint
Door Heater . . . . . . . . . . . . . . . . . . . . . . . . .100% (factory set)
For best overall performance of the incubator, the refrigera-
tion switch should be turned on for most applications. When
running Low/No humidity at high temperatures, the refrigera-
tion switch may be turned off.
The defrost switch must be turned on when the
temperature setpoint is 10°C, or below.
2.7 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 counterclock-
wise until the audible alarm sounds and the overtemp
indicator lights.
2. Turn the overtemp control knob clockwise approximate-
ly two units on the scale. The alarm should be silenced
and the overtemp indicator light should go out.
The overtemp safety thermostat is now set a few degrees
above the control temperature setpoint. When the cham-
ber temperature rises to the overtemp control point, the
alarm system will activate, 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
accommodate the change.
To prevent mineral buildup on heater coils and
humidity generator walls, it may be necessary to
clean the humidity generator and immersion
heaters with a non-metallic abrasive pad and
flush thoroughly every two to three months. Refer
to Section 4.2, Cleaning the Humidity Generator
and Immersion Heaters.
b. Connecting the Drain Line
The cabinet’s 3/8” MPT drain line connection is located on
the rear (lower left side) of the cabinet. A P-trap (Figure 2-1) is
included with the unit and must be installed on the connection.
To install the drain connection:
1. Using Teflon pipe thread tape, tape the threads on the
cabinet drain connection.
2. Using an open end adjustable wrench, install the P-trap
onto the connection. Make sure that the trap is posi-
tioned down.
3. Push a piece of 3/8” ID tubing onto the trap and direct
the tubing to a convenient drain. Install a hose clamp on
the tubing, if desired.
Figure 2-1
Cabinet drain P-trap
2.4 RS-232 Output Interface/Remote Alarm Connector
The Model 3940/3949 incubator is equipped with an RS-
232 Serial Communication Interface for the remote transmis-
sion of temperature and humidity data. A remote alarm connec-
tor is also included on the terminal strip.
Terminal Pin Descriptions, RS-232 (1-6)
and Remote Alarm Connector (7-9)
Figure 2-2
2 - 2
