Carbolite BLF 18/21 - Manual (Page 8)

BLF
8
MF23 – 3.11
4.0 M AINTENANCE
4.1 Routine Maintenance
No routine maintenance is required except for the replacement of consumable items as required.
The outer surfaces may be cleaned with a damp cloth. Do not allow water to enter the interior of
the case, tube or control box. Do not clean with organic solvents.
Lightweight ceramic fibre insulation can easily be marked by accidental contact. Some fine cracks
may be visible on the surface of the insulation, or may develop in the surface of the chamber due
to the progressive shrinkage of the insulation materials. Cracks are not usually detrimental to the
functioning or the safety of the furnace.
4.2 Calibration
After prolonged use the controller and/or thermocouple could require recalibration; see the
warning in section 3.5. This would be important for processes which require accurate temperature
readings or which use the furnace close to its maximum temperature. A quick check using an
independent thermocouple and temperature indicator should be made from time to time to
determine whether full calibration is required. Carbolite can supply these items.
Depending on the controller, the controller manual may contain calibration instructions.
4.3 After Sales Service
Carbolite’s service division (Carbolite Engineering Services) has a team of Service Engineers
capable of repair, calibration and preventive maintenance of furnace and oven products at our
customers’ premises throughout the world. We also sell spares by mail order. A telephone call or
fax often enables a fault to be diagnosed and the necessary spare part despatched.
Each furnace has its own record card at Carbolite. In all correspondence please quote the serial
number, model type and voltage given on the rating label of the furnace. The serial number and
model type are also given on the front of this booklet when supplied with a furnace.
To contact Carbolite Engineering Services or Carbolite see the back page of this manual.
4.4 Recommended Spares Kits
Carbolite can supply individual spares, or a kit of the items most likely to be required. Ordering a
kit in advance can save time in the event of a breakdown. Each kit comprises one thermocouple,
one sheath, one power thyristor, one door insulation piece, a set of elements and clips and braids. It
is advisable also to obtain element clamps and insulators (not included in kit). Individual spares
are also available.
When ordering spares please quote the model details as requested above.
4.5 Power Adjustment (Controller)
The furnace controller incorporates a power limit parameter OP.Hi which is usually inaccessible to
the operator.
Occasionally the power limit is set to zero to permit demonstration of the controls without the
heating elements taking power. In this case the power limit is accessible to the operator and may
be reset to its standard value of 100.
4.6 Power Adjustment (Thyristor)
The current-limiting thyristor stacks which control power to the elements are fitted with an
adjustable resistor which is factory set to limit the maximum current supplied. In the event of a
change of supply voltage, or the fitting of a new thyristor, further adjustment may be required.
The maximum element currents for the various models are listed in section 8.8. Please contact
Carbolite for further information.