15
Circuit Breaker
A double pole circuit breaker is located at the bottom of
the control section. It serves to turn electricity ON and
OFF and to protect the electrical circuit.
Fans
The fans, located in the rear of the heating section and
the control section, will run continuously as long as
electricity is supplied to the furnace, even when the
furnace panel circuit breaker is OFF. This serves to
remove residual heat after the furnace is turned OFF so
the heat does not cause damage to the controls.
Controllers
Your furnace’s controller consists of a microprocessor
based three-mode (Proportional, Integral, Derivative),
programmablecontrol with overtemperature protection
and appropriate output switching devices to control the
furnace. The digital readout continuously displays
chamber (upper display) and set point (lower display)
temperatures unless the scroll button is depressed.
If the scroll button is depressed and released, the lower
display will indicate output power (OP) or set point (SP).
This is referred to as the “short scroll”. Continued single
step depression of scroll button will cause lower display
to alternate between set point (SP) and output power
(OP).
To enter the main scroll list (list of all controller param-
eters that are accessed through front keyboard), the
scroll button should be held depressed. On the Automatic
Models, PR (program ramp rate) will appear. On the
Programmable Models, PR1 (program ramp rate 1) will
appear. To progress through the parameter list, the scroll
button must first be released, subsequent single step
depression will advance you through the list. Rapid
progression through the parameter list is achieved by
holding the scroll button depressed. (See Control Param-
eters for your particular controller for a list of param-
eters.)
NOTE
When performing operations on the
controller, remember that if you depress
and release either the “scroll”, “up”, or
“down” push buttons and more than 8
seconds elapse before the buttons are
used again, the display screen will
automatically switch back to displaying
set point temperature. If this happens,
you will have to step through each
parameter until you reach the point at
which the interruption occurred. The
parameter values you
adjusted earlier, however, will not be lost
or altered.
NOTE
Due to the High Temperature design of
the thermocouple, the controller will
indicate a temperature of 70°-90°C at
ambient temperature.
G
ENERAL
O
PERATION
OF
F
URNACE
