Carbon Monoxide Alarm User Manual

Page 19
3.3.1.2 Fresh air "zero" through mini-push-
buttons
(1) Turn the instrument on.
(2) Wait at least three minutes after turning the
instrument on to allow sensor readings to stabilize
fully before initiating the fresh air zero procedure.
(3) Remove the key pad cover exposing the four mini-
push-buttons.
(4) Verify that the instrument is in the Basic or
Technician operating mode. Switch modes (if
necessary) by simultaneously holding down the "+"
and"-" keys.
(5) Make sure the instrument is located in an area where
the air is known to be fresh.
(6) Press the push-button marked "Cal." The fresh air
calibration message will appear briefly in the meter
display.
(7) The fresh air calibration message is followed by the
zero-adjustment screen.
(8) The PhD
2
automatically zeroes the instrument
readings when the "Cal" button is pushed. An
information screen is briefly displayed while the
adjustments are being made, and another when the
adjustments have been completed.
(9) Pressing the large black MODE button causes the
calibration values in the memory to remain
unchanged from the last time a fresh air adjustment
was made. An information screen is displayed briefly
which verifies that the zero values have not been
changed.
(10) After completion of the zero adjustment the PhD
2
automatically returns to the gas reading screen
display.
3.4 PhD
2
span calibration
Please note: Calibration procedures for certain
“corrosive gas” toxic sensors (sulfur dioxide,
ammonia, chlorine, hydrogen cyanide, and hydrogen
chloride) differ slightly from the standard procedures
which follow. Section 3.4.1. discusses special
calibration procedures for these “corrosive gas”
sensors.
In the span calibration procedure, the PhD
2
sensors are
exposed to known concentration calibration gas.
Biosystems sells calibration kits and long lasting
cylinders of check gas specifically developed for easy
PhD
2
calibration. Customers are urged to use
Biosystems calibration materials when calibrating their
PhD
2
.
The Biosystems calibration kit for the PhD
2
(Biosystems
part number 1653) includes a foam lined carrying case
with room for up to 3 cylinders of calibration gas, a 1.0
liters per minute fixed flow rate regulator, and hose.
Calibration gases must be ordered separately.
Please note: The relative response of the
combustible gas (LEL) sensor may vary from one
combustible gas to another. The best results are
obtained when calibration is done using the same
gas that is expected to be encountered while actually
using the instrument, if this is known.
Please see Appendix D for a list of suggested
calibration gases.
The span calibration procedure may only be done while in
the Technician operating mode.
(1) Turn the instrument on and remove it from its
carrying case.
(2) Remove the keypad cover exposing the four push
buttons.
(3) Verify that the instrument is in the Technician
operating mode. Switch modes (if necessary) by
simultaneously holding down the "+" and"-" keys.
Each time that the operating mode is changed, the
meter screen will briefly indicate the current
operating mode.
(4) Turn the instrument off by pressing the MODE button
for three full seconds until the "release button"
message appears in the screen.
(5) With the unit turned off, press and hold down the
"Cal" button.
(6) While holding down the "Cal" button, press the
MODE button to turn the PhD
2
back on. The
calibration message will appear briefly on the screen.
This message is followed by a screen showing the
first gas to be calibrated.