Model 3911/3913 _________________________________________________________________________________Service
5 - 1
Section 5 - Service
Servicing must be performed by qualified service
personnel only!
De-energize all potential
sources of energy to this
unit and lockout/tagout
their controls.
5.1 Accessing the Electrical Components
To gain access to the electrical components, remove the
two screws located on the left side of the control panel with a
phillips screwdriver. The control panel is hinged and will swing
open.
5.2 Replacing the Overtemp/Undertemp Probe and
Thermostat
1. Remove the incubator ceiling by remove the screws
holding it in place.
2. Remove the top three screws from the top of the right
duct cover.
3. Lean the duct sheet out, and remove the Permagum seal
from around the probe access hole.
4. Remove the 15” copper capillary overtemp probe by
extracting the two plastic clips that hold the probe in
place.
5. Open the control panel by removing the two screws
located on the left side of the control panel.
6. Pull the overtemp probe up through the access hole and
into the control panel.
7. Follow the wires from the probe to the thermostat
mounted on the control panel. Clip the plastic ties hold-
ing the overtemp cable to the existing wiring.
8. Pull the overtemp knob on the control panel off.
9. Remove the two screws that hold the overtemp assembly
to the control panel.
10. Disconnect the two wires from the back of the thermo-
stat assembly.
11. Pull the entire assembly out of the panel, and remove the
unit.
12. Replace the thermostat and probe.
Note:
Reseal the probe access hole with Permagum and retie
the overtemp cable to the existing wires after replacing the
probe.
5.3 Replacing the Humidity/Temperature Sensor
1. Locate the probe mounting plate in the center of the
right side of the incubator interior.
2. Open the mounting plate by removing the screws that
hold it in place.
3. Locate the humidity sensor mounted on the inside of the
panel in a black housing. Note the angle of the probe.
4. Grasp and unplug the probe from the probe cable.
5. When replacing the humidity sensor, be sure to mount
the probe at the same angle as it was originally mounted.
5.4 Replacing the Optional Recorder and Probe(s)
1. Open the incubator door, and locate the probe mounting
plate attached to the center of the right interior wall.
Remove the mounting plate.
2. The recorder probe is attached to the lower end of the
back of the mounting plate. Remove the probe by care-
fully sliding it out of the housing.
3. Remove the screws securing the ceiling of the incubator
and remove the ceiling.
4. Remove the top three screws on both edges of the right
duct sheet.
5. Lean the duct sheet out in order to remove the
Permagum seal from around the probe access hole.
6. Remove the two screws located on the left side of the
control panel and open the control panel door. Remove
any Permagum from around the access hole.
7. Pull the probe(s) carefully up through the hole.
8. Follow the probe cable(s) to the back of the recorder,
and carefully clip any plastic ties holding the cable(s) to
other wiring.
9. Remove the three screws securing the recorder and pull
it carefully out from the front of the control panel.
10. Replace the recorder with the correct Thermo Forma
part.
Note
: When replacing the recorder and probe(s), retie the probe
cable(s) to the existing wires.
Contains Parts and Assemblies
Susceptible to Damage by
Electrostatic Discharge (ESD)
CAUTION
