ENMET PPM Formaldemeter™ htV-m - Manual (Page 7)

Formaldemeter
htV-m
ENMET Corporation
5
4.0 Calibration check and Adjustment
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.
General Information
Sensor sensitivity can change very gradually with time; so periodic recalibration may be required. It is advisable to check
calibration regularly to ensure that the instrument is functioning correctly.
A quick calibration check can be carried out by drawing a formaldehyde vapor sample of known concentration into the
instrument’s sensor and noting whether the displayed reading agrees with the expected concentration value.
The PPM Formaldemeter ™
htV-m
-m is supplied complete with a formaldehyde calibration standard and has a built in
thermometer essential for calibrating the instrument.
It is recommended that calibration check or adjustment be carried out at the approximate operational temperature.
4.1 Temperature & Humidity Sensor
1. Hold down the SAMPLE button and press the ON-OFF button once. Release the SAMPLE button.
2. The Instrument will briefly display: HEAt
3. The instrument will then show the temperature reading in oC, followed by: oC
4. The instrument will then display the humidity (in % RH), followed by: %rH
5. The instrument will cycle through these four screens until it is either switched off manually, or it will switch itself off after
30 seconds.
The Sensor used for the temperature and humidity readings is accurate to within ±3.0 %Rh for humidity, and ±0.4 oC for
temperature, within the operational limits for the instrument. To ensure the accuracy of the instrument the temperature &
humidity sensor is replaced with the instruments annual service.
4.2 The PPM Formaldemeter™
htV-m
Calibration Standard
The PPM Formaldehyde Calibration Standard consists of formaldehyde absorbed on a substrate in a glass tube from which a
headspace vapor sample can be drawn. Each standard is carefully manufactured to a high tolerance.
Effect of Temperature
The concentration of formaldehyde vapor generated in the calibration standard varies with temperature and for this reason, the
instrument has a built in thermometer and a temperature / concentration table is supplied.
Due to the effect of body temperature, handle the calibration standard only by the yellow end caps, to ensure temperature
equilibrium.
Temperature Equilibrium
The calibration standard should always be allowed to stabilize within the recommended temperature range of 15-29°C for at
least 1 hour before use.
Calibration Standard Expiration
Each calibration standard may be used for a maximum of 6 months (as indicated by the given expiry date), or a maximum of
100 samples. New calibration standards can be ordered from
ENMET Corporation. See Section 8.4 for reorder part numbers.
Formaldehyde Calibration Standard
Thi
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