ENMET PPM Formaldemeter™ htV-m - Manual (Page 8)

Formaldemeter
htV-m
ENMET Corporation
6
4.2.1 Calibration Check Procedure
Place the instrument and calibration standard together in a place where the temperature is stable for at least one hour before
commencing the calibration check to allow thermal equilibration.
Before carrying out a calibration check, the sensor must be clear of formaldehyde vapor from any previous samples. The
Temperature sensor must be read (as described earlier) and a note taken as this is vital for the calibration procedure.
Procedure
1. Place the calibration standard and the instrument on a work surface. Handle the calibration standard as little as possible
to avoid heating the tube, holding it by the yellow caps. Remove both end plugs.
2. Switch the instrument on by pressing the ON-OFF button once. Wait for the display to show:
0.00
3. Insert the nozzle into the sampling end of the tube. Ensure a good seal around the instrument nozzle by pushing the
calibration standard tube firmly against the instrument when taking a sample.
4. Press the SAMPLE button and wait until the internal sampling pump stops before removing the standard from the
instrument. Replace the end plugs in the calibration standard securely.
5. The display will flash between the following two screens for 10 seconds:
-. - - and 0.00
6. The display will then show a flashing,
-.- - as the sample is analyzed. After 60 seconds, the display will show a non-
flashing value, which is held until the instrument is switched off. This indicates the formaldehyde concentration in ppm.
7. Refer to the Temperature/Concentration look-up table on the standard tube. If the reading is within 5% of the value
shown in the table, then no re-calibration is required.
8. If re-calibration is required, follow the calibration adjustment procedure that follows.
Leave the instrument switched off for approximately 5 minutes to recover before commencing another calibration check,
adjustment or taking a sample.
4.2.2 Calibration Adjustment Procedure
Please read this section thoroughly before attempting to check or adjust calibration. Users are strongly advised to familiarize
themselves with the instrument before attempting to adjust the calibration and should follow the instructions carefully.
Under normal operating conditions, instrument calibration should require only minimal periodic adjustment. To see whether a
full recalibration is required, perform a calibration check first. Leave the instrument and calibration standard in a room where
the temperature is constant for at least one hour before calibrating to allow thermal equilibration.
Procedure
1. Place the instrument and calibration standard on a work surface
2. Handle the calibration standard only by the yellow end caps.
3. Press the ON-OFF button to switch the instrument on.
4. Wait for the display to show:
0.00
5. Remove the yellow plugs from both ends of the calibration standard.
6. Insert the instrument nozzle into the sampling end of the calibration standard. To maintain airtight contact between the
nozzle and the standard, push the standard firmly against the instrument.
7. Simultaneously depress and release both Cal
▲ and ▼ buttons.
8. The pump will be heard drawing a vapor sample and the screen will briefly show:
CAL
9. When the pump stops, remove the calibration tube and replace both yellow end plugs.
10. The display will show an increasing, flashing value for 60 seconds, followed by:
SEt
1.750
11. Read the temperature noted down recently and determine the required concentration reading from the lookup table on
the calibration standard, for example:
Temperature: 21°C
Reading: 2.13 ppm
12. Now use the Cal
▲ and
Cal
▼buttons to adjust the display reading to the required concentration.
13. Press the SAMPLE button to store this calibration value.
The display will show:
CA
L
Followed by:
End
The Formaldemeter ™
htV-m
will then switch off automatically. The instrument has now been recalibrated.