Thermo Scientific 48i Instruction Manual page 197

Thermo Fisher Scientific
Therefore, if only a barometer is available and not a vacuum pump, only
adjust the span setting.
A rough check of the pressure accuracy can be made by obtaining the
current barometric pressure from the local weather station or airport and
comparing it to the pressure reading. However, since these pressures are
usually corrected to sea level, it may be necessary to correct the reading to
local pressure by subtracting 0.027 mmHg per foot of altitude.
Do not attempt to calibrate the pressure transducer unless the pressure is
known accurately. ▲
Equipment Required:
Vacuum pump
WARNING The service procedures in this manual are restricted to qualified
service representatives.
If the equipment is operated in a manner not specified by the
manufacturer, the protection provided by the equipment may be
impaired. ▲
Equipment Damage Some internal components can be damaged by small
amounts of static electricity. A properly grounded antistatic wrist strap
must be worn while handling any internal component.
1. Remove the instrument cover.
2. Disconnect the tubing from the pressure transducer and connect a
vacuum pump known to produce a vacuum less than 1 mmHg.
3. From the Main Menu, choose Service > Pressure Calibration.
The Pressure Sensor Cal screen appears.
Note If Service Mode is not displayed, refer to
Mode" on page 7-4, then return to the beginning of this step.
4. At the Pressure Sensor Cal screen, press
The Calibrate Pressure Zero screen appears.
▲
▲
Servicing
Pressure Transducer Calibration
▲
▲
"Accessing the Service
▲
to select Zero.
Model 48i Instruction Manual 7-23