B.
Product Overheats
1.
The HEAT light goes
OFF with the
instrument switch.
The controller
shows a very high
temperature.
The controller is faulty.
The controller
shows a low
temperature.
The thermocouple may
have been shorted out or
may have been moved out
of the furnace.
The thermocouple may be
connected the wrong way
around.
The controller may be
faulty.
2.
The HEAT light does
not go off with the
instrument switch
and the fault persists
when a 2 A control
fuse is removed from
its fuse-holder.
The power
thyristor has
failed "ON".
Check for an accidental
wiring fault which could
have overloaded the
thyristor.
Isolate the furnace if this
fault persists.
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