Model 445580 & 445582 Version 3.3 July 2004
3
Calibration and Verification Procedures
The following procedures require 33% & 75% RH references available through Extech.
Verification (Checking the 33% or 75% RH Calibration)
Skip the verification and go directly to the Cal procedure below if it has already been
determined that the meter calibration is compromised or if the E2 display appears.
1. Insert meter’s sensor into the 33% or 75% salt reference bottle
2. Place the meter and bottle inside the meter case
3. Wait 40 minutes and then check if the reading is within the published specifications
Relative Humidity Calibration (33% and 75%)
For best results, store the meter and salt bottles in the closed case during the 40-minute
stabilization process. The 33% and the 75% calibrations must both be performed.
1. Start with the meter OFF.
2. Insert the meter’s sensor into the 33% salt reference bottle. Put the
meter and the bottle in the case and close the case. Allow the meter to
stabilize for 40 minutes. Note that for diagnostic purposes the
stabilization process can be shortened to 5 minutes.
3. Open the case but leave the pen in the bottle
. While holding down the
recessed CAL button with a paper clip, press and release the ON-OFF button.
Continue to hold down the CAL button, the unit will turn ON and the display will flash
once.
4. When only the F and C icons appear, release the CAL
button. After releasing the CAL button, the display will
indicate either F or C (depending on which one was
selected).
5. Press and hold the RESET button for 3 seconds. %MIN will appear in
the display after the RESET button is released.
6. Press and release the CAL button. ‘S’ will briefly
display followed by %MAX display.
7. Turn the meter OFF
. Insert the meter sensor into the
75% salt reference bottle. Put the meter and the bottle in the case and close the case.
Wait 40 minutes.
8. Open the case but leave the pen in the bottle
. While holding down the recessed CAL
button with a paper clip, press and release the ON-OFF button. Continue to hold down
the CAL button, the unit will turn ON and the display will flash once.
9. When only the F and C icons appear, release the CAL
button. After releasing the CAL button, the display will
indicate either F or C.
10. Press and hold the RESET button for 3 seconds. %MIN will appear in
the display after the RESET button is released.
11. Press and hold the RESET button again for 3 seconds. %MAX will
appear after the key is released.
12. Ensure that %MAX is displayed and
then press CAL. ‘S’ will appear briefly
and the meter will return to normal
operation. Turn the power OFF;
calibration is complete.
