WIKA 70-8xx - Manual (Page 13)

13
11472988.02 04/2013 GB/D/F/E
WIKA operating instructions expansion thermometer, model 70
GB
Adjusting the set pointer (with micro switch)
The adjustment of the set point is achieved using the adjustment key in the window.
The set pointers for the micro switches are freely adjustable over the full scale range. For
reasons of switching accuracy and the service life of the mechanical measuring systems,
the switch points should be between 10 % and 90 % of the measuring range.
The switch points with a fixed setting to customer requirements cannot be altered
subsequently.
As a result of surface oxidation on the contact surfaces, especially with intrinsically-safe
switching (small voltages and low currents), flaws that can lead to contact erosion can
arise as a result of the developed isolation resistance and with higher contact loads.
9. Maintenance and cleaning
9.1 Maintenance
These expansion thermometers are maintenance-free.
The indicator and switching function should be checked once or twice every year. To
do this, the instrument must be disconnected from the process and checked using a
temperature calibrator.
Repairs must exclusively be carried out by the manufacturer or by appropriately qualified
personnel.
9.2 Cleaning
CAUTION!
„ Prior to cleaning, disconnect the instrument from the mains.
„ Clean the instrument with a moist cloth (soap water).
„ Electrical connections must not come into contact with moisture.
„ Ensure that all parts are dry before the power is switched on again.
„ Wash or clean the dismounted instrument before returning it, in order to
protect persons and the environment from exposure to residual media.
„ Residual media at the dismounted instrument can result in a risk to
persons, the environment and the equipment. Take sufficient precautionary
measures.
For information on returning the instrument see chapter 11.2 "Return".
8. Zero adjustment / 9. Maintenance and cleaning