Thermo Scientific BF51634BC-1, Installation And Operation Manual

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Troubleshooting
10-2 Thermo Scientific
Controller actual furnace temperature display
does not increase or decrease when the fur-
nace is heating
3. Check all thermocouple wires for a
short.
a. Visually inspect the thermocouple
wires for a cut in the wire.
b. Check that the wires at the
connections do not touch each other.
4. Check the controller. Use a secondary
temperature display device, design for
Type B thermocouple, to check
thermocouple temperature. If
thermocouple temperature is correct,
the controller may be faulty.
Coating on heating element crack.
Heat element above 995 °C to restore coat-
ing.
Foreign substance on heating element
Furnace temperature is too high Thermocouple:
a. Check the thermocouple visually for
breaks. If a break is evident replace
the thermocouple.
b. Check the ceramic thermocouple
support tube for cracks which result
in the thermocouple wires touching
in breaking area. If the wires are
touching break the thermocouple.
c. Check all thermocouple connections.
Connections should be clean and
free of corrosion.
d. Check the reductions of diameter in
the wire immediately behind the
welded junction. If there is reduction,
replace thermocouple.
e. Check for reduction of diameter in
the wires immediately behind the
welded junction. if there is reduction,
replace thermocouple.
Heating element fail to shut off.