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300710168_002_C1 - 01/2018 - © Leybold
Maintenance
Atmosphere and vacuum adjustment
Every TTR 91 R is individually adjusted before shipment, however thermal conductivity gauges can drift with time or
as contamination builds up on the filament. Use the procedures outlined below to adjust the atmosphere and vacuum
settings of the gauge. The frequency with which they should be repeated will vary depending on the level and nature
of the contamination associated with the process.
Adjustment of TTR 91 R
Atmosphere adjustment
1.
Switch on the power supply to the TTR 91 R and allow it to operate at atmospheric pressure for at least 10
minutes. Ensure that the green status LED is lit.
2.
Press the 'CAL' button. The status LED turn amber and the gauge will automatically adjust to read
atmospheric pressure. Do not hold the ‘CAL’ button down for longer than 5 seconds (see ‘Adjustment for
new tube’ below).
