Page 167025 Instruction Manual (Rev. 2)In case you need to remove the valve block, please refer to paragraph 7.2-Access to theInside of the Instrument. The block is fastened by two M5 screws, whose heads are easi-ly located on the back of the supporting plate.7.2 Access to the Inside of the InstrumentAccess to the inside of the instrument is immediate.Make sure first that the power cord is disconnectedfrom its power outlet (see SAFETY CONSIDERATION).Figure 10 “Access to the Inside of the Instrument”Remove the six M4 oval-headed screws (indicated in Figure 10 “Access to the Inside ofthe Instrument”, on page 16) with the 2.5 mm Allen wrench provided.Pull out the plate/wall assembly, see Figure 10 “Access to the Inside of the Instrument”.7.3 Rate CalibrationIf the stroke frequency (see paragraph 6.2-Frequency) does not agree with the indicationon the LED display (see paragraph 4.2-Rate), it is a simple matter to recalibrate the elec-tronic circuit.In fact, the unavoidable aging of the components, vibrations, accidental knocks or someM4 SCREWS, NOT TO BE LOOSENEDIN THE COURSE OF NORMALMAINTENANCE OPERATIONREMOVE THE 6 INDICATEDM4 SCREWS FOR OPENINGTHE INSTRUMENT