Vaisala HMK15 - Manual (Page 23)

Chapter 4 ________________ Instructions for the Calibration of Humidity Instruments
VAISALA _________________________________________________________ 21
Thermometer
The calibrator includes a thermometer which can contain
either mercury or red capillary liquid. If the thermometer
contains mercury, it is delivered with a calibration
certificate. The accuracy of the mercury thermometer is
sufficient for checking the transmitter's temperature channel
if desired. The mercury thermometer has been calibrated at
five points and the result is traceable to the Measurement
Standards Laboratory of the Centre for Metrology and
Accreditation in Finland. For more accurate results, use the
corrections given in the calibration certificate or their
interpolated values. Consider also the parallax error which
may occur while reading the results. The mercury
thermometer should be recalibrated within three years in
order to maintain the traceability.
The manufacturer of the thermometer with red capillary
liquid provides it with a factory calibration certificate. As
the accuracy and stability of this kind of a thermometer are
inferior to those of a mercury thermometer, it is not
recommended to be used for checking the temperature
channel of the transmitter.
The sleeve at the end of the thermometer's protective tube
can be used in two different positions. The thermometer is
delivered with the sleeve in such a position that it protects
the part containing the capillary liquid. When turned the
other way round, it acts as an adapter when the thermometer
is inserted into the 13.5 mm hole (see Figure 8).
0606-171
Figure 8 The sleeve protects the part with capillary
liquid (on the left) or acts as an adapter (on
the right)