Carbolite CTF - Fault Analysis; Furnace Does Not Heat Up; Furnace Overheats

1700-1800° Tube
FAULT ANALYSIS
A. Furnace Does Not Heat Up
1.
The HEAT light
is ON
Æ
An ohm meter applied to
the element circuit shows
an open circuit
Æ
A heating element has failed
2.
The HEAT light
is OFF
Æ
The controller shows a
very high temperature
or a code such as S.br
Æ
The thermocouple has broken
or has a wiring fault
Æ
The controller shows a
low temperature
Æ
The door switch may be faulty
or need adjustment
Æ
The thyristor fuse may have
blown
Æ
The power thyristor could be
failing to switch on due to
internal failure, faulty wiring
from the controller, or faulty
controller
Æ
There are no
lights glowing
on the
controller
Æ
The SUPPLY light is
ON
Æ
The controller may
be faulty or not
receiving a supply
due to a faulty switch
or a wiring fault
Æ
The SUPPLY light is
OFF
Æ
Check the supply
fuses and any fuses in
the furnace control
compartment
B.
Furnace Overheats
1.
The HEAT light
goes OFF with the
instrument switch
Æ
The controller shows a
very high temperature
Æ
The controller is faulty
Æ
The controller shows a
low temperature
Æ
The thermocouple may have
been shorted out or may have
been moved out of the furnace
Æ
The thermocouple may be
mounted the wrong way round
Æ
The controller may be faulty
2.
The HEAT light
does not go off with
the instrument
switch and the fault
persists when a 2A
control fuse is
removed from its
fuse-holder
Æ
The power thyristor has
failed “ON”
Æ
Check for an accidental wiring
fault which could have
overloaded the thyristor.
Isolate the furnace if this fault
persists.
7.0
14 MF32