2009 by ELTRA GmbH Germany – July 2009 – Service Manual Thermostep
Page 26
At e.) In rare cases the gas pressure switch for compressed air can be defective. The switch
checks if the input pressure of compressed air is at least 2 bar and switches on flow. If the
pressure is lower than 2 bar the switch doesn’t open the tubes and no compressed air is passed
into the instrument. The message: “No compressed air availeable !” is shown additionally. Is
pressure of compressed air higher than 2 bar and still error then the switch has to be changed.
Close cover.
Remove tube of compressed air at the backside of the instrument and check if it is free
(see Fig. 2.1).
Remove the metal sheet with the gas pressure switches carefully at the RHS by
unfasten the 3 mm allen screws.
Fig. 2.6: RHS – Metal sheet with Gas pressure switch
You see the two gas pressure switches (one for compressed air and one for gases), that
are covered by a plastic hat. Remove the plastic hat and check the colour of the
connected cables.The gas pressure switch is connected by a yellow and a black cable.
Remove the cables by soldering.
Remove the switch with an 14 mm open-ended wrench from the metal block. Please
note that there is a rubber lip between switch and metal block!
Replace the switch using the rubber lip.
Solder the cables at the new switch.
Replace the plastic hats at the switches and fasten the metal block again.
2.4
Balance unstable
Error message: “Balance is unstable, can’t tare!”
An unstability of the balance can be caused by:
