Hach-Lange LT 200 Thermostat - Manual (Page 69)

68
Maintenance
6.2 Instrument test
The temperature shown in the display
corresponds to the temperature in a closed
LANGE cuvette filled with an aqueous medium.
During the heating phase, the real block
temperature in the vicinity of the heater may be
higher than the temperature shown in the
display.
An empty LANGE cuvette (LCW 906), glycerol
(approx. 5 ml) and a stem-type thermometer
calibrated over the range from 95 °C
– 155 °C
(type 67C to ASTM) are needed to check the
block temperature.
• Fill the cuvette with glycerol at room
temperature and insert the thermometer
until it touches the bottom of the cuvette.
• When the thermometer is in the cuvette, the
level of the glycerol must be 62 mm
+/- 0.5 mm.
• Insert the cuvette in the centre opening of
the second row of the test block.
• Start the temperature program for 100 °C,
60 min for this block.
When the heating phase is complete, the
temperature shown by the thermometer should
be equal to the temperature shown in the
display.
6.3 Changing the protective covers
To change the protective covers, proceed as
follows:
1. Half open the protective cover (approx.
45 °) and take hold of it above the external
hinge with your thumb inside (
Figure 4 ).