Ivoclar Vivadent P300 - Manual (Page 26)

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7.3 Special programs
Press the ”cogwheel” key (Settings/Information).
Vacuum pump test program
With the program, the vacuum performance of the furnace vacuum
system can be automatically tested. For that purpose, the achieved
(minimum) pressure in mbar is measured and indicated. If the
pressure value is below 80 mbar (hPa), the vacuum performance of
the system is adequate.
Keypad test
Each time the keypad is pressed, a short beep sounds. The keypad
test can be ended by pressing ESC.
Heating muffle test program
The quality of the heating muffle may be automatically checked by
means of the heater test (duration: approximately 7 minutes).
The heater test should only be conducted with the empty
firing chamber, since an object in the chamber (e.g. firing
tray) may influence the test result. Conduct the heater test
immediately after switching on the furnace and before any
actual firing procedures are conducted. If the furnace is too hot, an
incorrect heating muffle quality will be indicated. If the heating
element quality falls below 50 %, replacing the heating element is
recommended.
Dehumidification program
The condensation of water in the insulation of the firing chamber
and the vacuum pump will result in a lower vacuum and thus to
impaired firing results. For that reason, the furnace head should be
kept closed when the furnace is switched off, in order to prevent the
absorption of humidity. Start the dehumidification program if
required (humidity in the insulation).
Cleaning Program
The cleaning program is used to "clean" the heating muffle
(duration: approximately 17 minutes). After a cleaning program, it is
recommended to calibrate the furnace. In case of problems with
discolouration of the ceramic, we recommend replacing the firing
table or the firing tray material.
7.4 Calibration
Furnace calibration (Silver Test)
The sheathed thermocouple may be subject to changes
with affect the furnace temperature, depending on the
mode of operation. Check furnace temperature with the
”Silver Test” at least once a year and adjust if necessary.
For that purpose, the furnace features a special calibration program.
Procedure:
a)
The Furnace must be at operating temperature (switched on for
at least 60 minutes) and have a stand-by temperature of 403 °C
(757 °F).
b) You can access the Settings menu by pressing the "Information /
Settings" key.
Subsequently, press and hold
the right cursor key (79) until
the following display appears.
To select the calibration pro-
gram press the ENTER key.
The following is displayed:
Recalibration
A change in temperature of
”+/-” 100 °C (180 °F) is possible in
the Programat P300/G2. Select the
calibration program to activate the
calibration keys + and –. The
program must not be started for
this purpose. The latest calibration
value is indicated on the display.
– If the silver wire has not started
to melt after the Silver Test,
recalibrate using the + key
(Figure A)
– If the silver wire has melted
down to a ball after the Silver
Test, recalibrate using the – key
(Figure C).
Every time a calibration key is
pressed, the set temperature
changes by 1 °C (1.8 °F)
Experience has shown that a
recalibration of 5 °C (9 °F) is
appropriate, which means pressing
the relevant key five times.
While the calibration keys are in use, the calibration value in °C (°F)
is shown in the Display. Entering the calibration value does not have
to be confirmed with ENTER. We recommend that you do not
recalibrate the furnace immediately before it reached the holding
temperature or during the holding time of the Silver Test program.
Repeat the Silver Test until the silver wire starts to melt correctly
(Figure B).
7.5 Service note
When the service note (Hint 1700) appears for the first time, two
years have passed or the heating muffle has more than 1200 firing
hours. For that reason, Ivoclar Vivadent recommends to have the fur-
nace serviced. Please see your Equipment Service Pass for further
information. The interval until the next service note can be selected
once in the advanced settings (see Chapter 5.5.1).
7.6 Stand-by
We recommend keeping the furnace head closed, especially if the
temperature drops below 150 °C (302 °F).
Fig. A Temperature too low
Fig. B Temperature just right
Fig. C Temperature too high
Sample holder
silver wire
Firing plate (6)
c) Insert silver wire into the Ivoclar Vivadent sample holder.
d) Place the sample holder with the silver strip in the centre of the
firing plate (6).
e) Press START (if error message Error 14 appears, the furnace
temperature is still too high fort he ”Silver Test”
(>410 °C/770 °F)). The furnace closes automatically at the correct
temperature and the program starts.
If the silver wire has started to melt (and has a ”pitted”
appearance) at the end of the program, the furnace
temperature is correctly calibrated (Figure B). If not,
recalibration is necessary.