Hanna Instruments HI 2221, Instruction Manual, Page: 27 / 44

27
TEMPERATURE CALIBRATION
(for technical personnel only)
G L P
C F M
All the instruments are factory calibrated for temperature.
Hanna Instruments’ temperature probes are interchangeable and no
temperature calibration is needed when they are replaced.
If the temperature measurements are inaccurate, temperature recalibra‑
tion should be performed.
For an accurate recalibration, contact your local Hanna Instruments, or
follow the instructions below.
• Prepare a vessel containing ice and water and another one containing
hot water (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 instrument off, press and hold down the CFM & SETUP
keys, then power on the instrument. The “ CAL ” tag will appear and
the secondary LCD will show “ 0.0 ºC “.
• Submerse 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 “.
• Submerse the temperature probe in the second vessel 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 the hot water.