Metrohm 799 GPT Titrino - Manual (Page 207)

4.2. Diagnosis
799 GPT Titrino 203
• Press .
The internal dosing unit expells twice the volume of 3.5 ml.
• Remove exchange unit.
• Check spindle zero position, see Fig. 6.
0.2 - 0.6 mm
Fig. 6 Fig. 7
The spindle must be 0.2 - 0.6 mm below the edge of the sliding plate.
The bar of the stopcock coupling must be exactly parallel to the lateral edges of the GPT
Titrino, see Fig.7.
• Reinsert Exchange Unit.
Titrino fills.
The display of before reappears.
• Knob 'dV/dt' to right stop.
• Press the key (on instrument) until the piston rod reaches the top and at the
same time measure the time from start to end.
XXX X ********
cylinder empty !
mind selected language!
Spindle remains at maximum position. The transit time of the spindle is 20 s.
• Measure spindle lifting (can be performed only if the 3.496.0070 Dummy Exchange
Unit is inserted or the locking switch (in right hole) is carefully operated with a
screwdriver after removal of the Exchange Unit).
From the start point, the spindle travels 80 mm. Instead of the spindle height, the expelled
volume can be measured (corresponds to max. vol. of Exchange Unit used).
• Press (on instrument) and simultaneously measure the time until the GPT
Titrino is again in the 'ready' position.
Times for filling: per stop cock cycle 1 s
for filling 20 s (Tolerance: 10 %)
The following generally holds: Spindle and stopcock must move at a constant speed
(noise!). In the filling setting, the stopcock coupling must position the lever of the Exchange
Unit correctly at the left stop (with virtually no play and without sticking).
• Set potentiometer 'dV/dt' to left stop.
• Press (on instrument) at same time and use a stopwatch to measure the
time for 1/10 of the cylinder volume to be expelled. The time should be ca. 76 ... 126
s.
• Set potentiometer 'dV/dt' to right stop.
• Press .