PRONOVA FOS/TAC 2000, User Manual

FOS/TAC 2000 

MAINTENANCE, REPAIR, CUSTOMER SERVICE 

812-04.2015-EN 

FOS/TAC 2000 User Manual 

19 

9.1

Maintenance of the pH electrode 

 
 
On completion of the measuring process, always rinse the electrode, dry and dip in KCl solution. For this purpose, fill KCl solution 

into the protective sleeve to a level of approx. 10mm and push the sleeve over the electrode. In order to prevent drying out, check 
the filling level in the cap and, if necessary, top up if the electrode has not been in use for a longer period of time. 

 
During transport or storage, KCl solution can leak from the protective cap and produce crystalline, white potassium chloride. This 
salt layer has no influence on measuring capability and can be easily rinsed off with water. 

 
An extended response time, a reduced gradient or an offset shift can be caused either by electrode soiling or ageing. Every 
electrode ages as a consequence of the exchange processes at the glass membrane even if the electrode is not used. High 

temperatures, polarization, short circuit or exposure to chemicals can significantly reduce the life of the electrodes. In the case of 
electrodes with the possibility to top up electrolyte, the fluid level of the electrolyte solution must be checked at regular intervals. The 

level of the reference electrolyte must always be several centimetres above the fluid level of the measuring solution. When 
necessary, KCl solution (3mol/l) must be topped up with the syringe through the refill opening at the shaft after removal of the seal.  
 

When changing the electrode, it is important to ensure 
that the protective basket is adjusted as shown in the 
illustration when the new electrode is fitted. 

9.2

Changing the hose of the peristaltic pump 

The hose of the peristaltic pump should be changed after approx. 250 measurements, but in no case later than after one year.  
 
 

Possibility of aggressive media residues. 
Wear protective glasses and suitable protective clothing when dismantling, repairing or cleaning the pump! 

 
Before changing the pump hose, proceed as follows in order to drain the hoses: 
 
Place an empty beaker onto the magnetic stirrer and pull the suction hose from the bottle containing the titration solution. 
In the main menu, select the “Calibration” option and subsequently “Peristaltic pump” and press <OK> in order to start the pump. 

The process ends automatically after two minutes or it can be stopped earlier by pressing <ESC>. 
 
 

Calibration 
Peristaltic 
Pump with 
   < OK > 

Calibration           
   active 
 

 __________ 
 

OK 

Calibration 
 
pH Electrode

Perist. Pump 

Measuring 

Calibration 

Stirrer 
A/D Values

OK 

OK