7. MAINTENANCE
Fan Filter
The maintenance frequency required by the Hot Spot 110 furnace will vary depending on how it is
used. During normal use it is important to keep the fan filter clean and remove contaminates from
the furnace chamber before each firing. See appendix A #14.
Insulation
It is normal for the ceramic fiber insulation to crack. As long as the insulation remains in place the
furnace will operate normally. Eventually the insulation will need replacement. Please contact
Zircar Zirconia, Inc. for parts and instructions to replace the furnace lining. Consider returning the
furnace to our factory for relining.
Thermocouple
The type B thermocouple will age with time and should be calibrated on a regular basis. The
complimentary box of single use Precision Temperature Control Rings (PTCR) included with the Hot
Spot may be used as furnace calibration check or as a record of an individual firing. For a calibration
check fire a PTCR ring to 1500 C, ramping at 120 C/hour during the last 200 C of the ramp. Hold at
1500C for one hour. Measure the outside diameter of the fired ring and compart to the chart to
determine the actual soak temperature. Large differences (>10 C) between measured ring and
program temperature indicate that the thermocouple is out of calibration and should be replaced.
For video instructions on how to replace the thermocouple go to
www.zircarzirconia.com/technical-documents/procedure-replacing-hotspot-thermocouple/.
Heating Elements
Eventually a heating element will require replacement. Elements are very fragile and can be broken
while changing other elements. Therefore it might be best to replace all four elements at one time if
they show signs of deterioration. If only one element is to be replaced, take care to prevent any
stressing of the terminals of the other elements.
Replace heating elements as follows:
1.
Unplug the furnace.
2.
Remove the top cover by unscrewing the 2 rear bolts and opening the furnace door and
unscrewing the front bezel bolt (see appendix A #9, 10, and 6).
3.
Unclamp the aluminum braid from the element terminal.
4.
Remove the used element by lifting its holder straight up and out of the furnace.
5.
Loosen the clamping bolt on the element holder and remove the used element. Take care not
to break the insulation tab which fits between the terminals of the holder. Replace any broken
tabs.
6.
Unpack a new element by placing it on a firm surface and cut the tape between the terminal and
the wooden brace with a razor blade or Exacto knife. Carefully remove the tape and the wooden
brace taking care not to flex the element.
7.
Reassemble the element holder with the new element so that the element terminals extend out
of the holder the same length as originally set.
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R-110M-01 Rev00
