A list of certification companies is included on the
Thermo Electron website, or call the Technical Services
Department. See Page iii.
9.5 Blower Control
Live voltage is present on the control terminals
of the switches and dials on the front of the blow-
er panel. Avoid touching these controls when
reaching into the control panel and making any
adjustments.
Blower Speed Control
- The blower speed control is accessed
from the rear of the control panel by removing the screw on the
exterior top and thumbscrew located at the bottom of the con-
trol panel. Swing the control panel door open. The blower
speed is adjusted by turning the screw on the variable resistor
mounted on the circuit board adjacent to the controller. (Refer
to Figure 9-1) Turning the screw clockwise increases air veloci-
ty; counterclockwise decreases it.
Model 1280 Series ____________________________________________________________________Routine Maintenance
9 - 3
The blower speed is factory-set and should only be
changed by a qualified technician.
Measuring Blower Motor Voltage
- Both blower motor
voltage and line voltage are measured at the three termi-
nal connectors at the top of the circuit board. Refer to
Figure 4-5.
9.6 Receptacle Fuses
Receptacle Fuses
(7 Amp - Models 1284/1285, 3 Amp -
Models 1286/1287) - The receptacle fuses (2), located
directly below the blower motor/lights Reset button, are
for the receptacles only. If an overload occurs, the fuses
will open and require replacement.
Note:
• Turn the power off.
• Unplug the unit.
• Replace the fuses -
P/N 230182, 7 Amp, ¼” x 1¼”
P/N 230166, 3 Amp, ¼” x 1¼”
(Two spare fuses are located in a bracket on
the inside of the control panel.)
