Hanna Instruments HI 250 - Manual (Page 22)

22
• Immerse the temperature probe in the second vessel as near as possible to
the reference thermometer. Allow a few seconds for the probe to stabilize.
All the instruments are factory calibrated for temperature.
Hanna’s temperature probes are interchangeable and no temperature
calibration is needed when they are replaced.
If the temperature measurements are inaccurate, temperature recalibration
should be performed.
For an accurate recalibration, contact your dealer or the nearest Hanna
Customer Service Center, or follow the instructions bellow.
• Prepare a vessel containing ice and water and another one containing hot
water (at a temperature of around 50 ºC). Place insulation material
around the vessels to minimize temperature changes.
• Use a calibrated thermometer with a resolution of 0.1 ºC as a reference
thermometer.
• With the instruments off, press and hold down the CAL&LOG keys, then
power on the instruments. The “CAL” tag will appear and the secondary
LCD will show 0.0 ºC.
• Immerse the temperature probe in the vessel with ice and water as near
as possible to the reference thermometer. Allow a few seconds for the probe
to stabilize.
• Use the ARROW keys to set the reading on the secondary LCD to that of
ice and water, measured by the reference thermometer. When the reading
is stable and close to the selected calibration point, “READY” tag will
appear and “CFM” tag will blink.
• Press CFM to confirm. The secondary LCD will show 50.0 ºC.
TEMPERATURE CALIBRATION
(for technical personnel only)
C
CAL
C
CAL