20 C4 Manual Rev 7.5.2
COOL indicator lights when cooling is active, typically during the time the
cryogenic valve is open on cryogenically cooled units.
HEAT indicator is pulsed along with the on and off function of the heaters.
These indicators are active in all modes of operation.
RUN indicator shows whether the chamber temperature is being controlled.
2.1.3 Mode Switch
The Mode Switch is used to apply power to the chamber and to select the mode of
operation. It is a 5 position rotary switch arranged as follows:
The OFF position removes the power from heating and cooling and compressor
control circuits of both the controller and the chamber or thermal platform.
CAUTION: Placing the mode switch in the OFF position
does not remove all power from either the controller or the
chamber or thermal platform. Only the heating, cooling,
and compressor control circuits are turned off. Full line
voltage potential is still available in many places in both the
controller and the chamber or platform. See servicing
warnings and instructions in the appendix of this manual.
Moving the rotary switch changes the mode of operation of the chamber. The
different modes are described in detail in separate sections of this manual. When
the rotary mode switch is moved to a new position, other than OFF, the
temperature control loop, if running, is turned off, heating and cooling are
disabled but the chamber blowers will continue to run unless disabled via setup