Bacharach Snifit 40 User manual

Snifit Model 40
Carbon Monoxide Analyzer
Introduction
Designed for HVAC professionals and utility person-
nel, the Snifit Model 40 Analyzer is ideal in checking
for the presence of CO in rooms and garages, or
around registers, furnaces, stoves, hot water heaters
and other types of combustion appliances. Used in
conjunction with your Digital Multimeter (DMM), the
Snifit samples the surrounding air and provides a
voltage output that is proportional to the detected CO
concentration that is then displayed on the DMM.
Features
• Measures 0 to 1999 ppm CO in room air
• Sensitive CO sensor will last up to 2 years
• Output of 1 mV/ppm CO
• Compact pocket size
• Low battery check
• Manual zero adjust
• Factory calibrated on 100 ppm CO
• Simple field calibration
• Auto power-off after 35 minutes
• Single 9V battery provides at least 1500 hours of
operation
Bacharach, Inc.
625 Alpha Drive, Pittsburgh, PA 15238
Phone: [phone] Fax: [phone]
Web: www.bacharach-inc.com
Printed in U.S.A. ® Registered trademarks
Instruction 19-9200
Rev. 0  October 1997
®

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Figure 1. Snifit 40
Specifications
Gas Monitored ............Carbon Monoxide (CO)
Range ..........................0 to 1999 ppm
Accuracy......................± (5% of reading + 5 ppm)
Resolution ...................1 mV/ppm CO
Response .....................≤30 sec. to 90% of final value
Power...........................9V battery
Battery Life ................1500 hours minimum
Temperature Range ...32 to 104 °F (0 to 40 °C)
Case Material .............High impact plastic
Weight .........................0.25 lb (0.11 kg) without battery
Dimensions .................5.5" L x 2.0" W x 1.6" H
(140 x 51 x 41 mm)
Operation
Turning the Snifit On/Off
If not already done,
install a 9V battery as
described under
Battery Installation.
Turn on the Snifit by
pressing its Power On
button. The Power On
LED indicates when
the instrument is
operating.
Turn off the instru-
ment by pressing the
Power Off button (or
the instrument will
automatically shut off
after approximately
35 minutes).
ZERO
ADJUST
SPAN
ADJUST
POT.
POW ER O N
POW ER O FF
POW ER O N
LED
BATTERY
OK LED
BATTERY
TEST
DATA
CABLE
VOLTM ETER
CONNECTOR

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Voltmeter Connection
Connect the Snifit to a voltmeter using the supplied
Data Cable (see Figure 1). We suggest using a 3½
digit or greater Digital Multimeter having a 2 VDC
range or auto ranging capability, a 10 MΩor greater
input impedance, and an accuracy of at least ±1mV.
Zeroing the Sensor
Turn on the Snifit and allow the voltmeter reading to
stabilize – approximately 30 seconds. Then with the
instrument sampling fresh air (air that is free of CO),
adjust the Zero Adjust knob at the top of the instru-
ment for a voltmeter reading of 0 ±1 mV.
If you’re not sure about the quality of the surrounding
air, you can apply a blend of Oxygen/Nitrogen gas to
the sensor as described under Calibration.
Checking for CO
Important! Ensure that the sensor grille at the rear of
the instrument is unobstructed and open to the atmo-
sphere. A quick instrument check can be performed by
allowing the smoke of a blown-out match to enter into
the sensor grille. This should cause the indicated CO
level to increase.
After the Snifit has been connected to a voltmeter and
zeroed, simply hold the instrument in the area that
you suspect the presence of CO gas. If CO is present,
the voltmeter will indicate the concentration of CO in
1 mV per ppm. For example: a voltmeter reading of
150 mV indicates a CO concentration of 150 ppm.
Battery Check
For accurate CO readings, pressing the Batt Test
button must cause the Batt Test OK LED to light. If
this LED does not light, replace the battery as
described under Battery Installation.

Figure 2. Calibration Equipment Setup
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Calibration
Important! For accurate Snifit operation, periodic
calibration of its CO sensor is required.
To calibrate the CO sensor, you will need the equip-
ment listed under Accessories. Note that the Zero Gas
Cylinder is needed only if you’re unsure about the
quality of the surrounding air for zeroing purposes.
Calibrate the sensor to a known concentration of CO
gas as follows:
1. Assemble the calibration equipment per Figure 2.
2. Zero the instrument as previously described under
Zeroing the Sensor.
If necessary, you can use the calibration cup to apply
a blend of Oxygen/Nitrogen gas directly over the
sensor by attaching a zero gas cylinder to the
regulator and adjusting the regulator knob for a
flow rate of 2 SCFH.
3. Push the Calibration Cup over the sensor housing.
4. Attach a CO Span Gas Cylinder to the regulator.
Then apply span gas to the sensor by adjusting the
regulator knob for a flow rate of 2 SCFH.
1
234
Parts Show n:
1.C O Span G as C ylinder,51-1994
2.R egulator,03-4318*
3.Tubing,03-6351*
4.Flow m eter,06-6163*
5.C alibration C up Assem bly,23-2156**
* P a rt o f C a lib ra tio n K it 2 4 -7 0 5 9
** PartofTool/C up Kit19-3242
5
PUSH CALIBRATION CUP
OVER SENSOR HOUSING

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Figure 3. Battery
Location
5. Allow span gas to flow until the voltmeter reading
stabilizes – approximately 3 minutes. Then, using
Calibration Tool 06-9453 (supplied in Calibration
Tool / Cup Kit 19-3242), turn the Span Adjust
potentiometer until the CO level indicated by the
voltmeter reading matches the concentration
stamped on the Span Gas Cylinder.
6. Calibration is now complete. Turn off the regulator
and remove the calibration equipment.
Maintenance
Battery Installation
Remove the slotted screw from
the rear of instrument; then
lift off the front case.
Install a 9V Alkaline battery
(Duracell MN1604 or equiv.) in
the location shown in Figure 3;
then reinstall the front case.
Sensor Replacement
The sensor needs replaced when it can no longer be
calibrated to the Span Gas Cylinder value using the
Span Adjust potentiometer.
1. See Figure 4. Remove the slotted screw from the
rear of instrument; then lift off the front case and
remove the printed circuit board assembly.
2. Unplug the old sensor and dispose of it properly.
3. Inspect the sensor gasket and filter. Replace an
item if is torn, deformed, or contaminated with dirt.
4. Remove thewire-jumper fromthe pinsof thenewsensor;
plug in the sensor; then reassemble the instrument.
5. Calibrate the new sensor.

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Replacement Parts
Item Part No.
CO Sensor .......................................................... 19-7061
Gasket ................................................................ 19-3234
Filter .................................................................. 19-3244
Accessories
Item Part No.
Calibration Kit .................................................. 24-7059
Calibration Tool / Cup Kit............................... 19-3242
Span Gas Cylinder, 100 ppm CO in air........... 51-1994
Zero Gas Cylinder, 20.9% O2in Nitrogen ....... 51-7131
Bacharach Service Center
Replacement parts and accessories can be obtained by
contacting the following Bacharach Service Center:
Bacharach, Inc.
625 Alpha Drive
Pittsburgh, PA 15238
Phone: [phone]
FAX: [phone]
Figure 4. Sensor Installation
CO
SENSOR GASKET
FILTER
W ARNING!
Remove
ju m p e r-w ire
fro m p in s b e fo re
in s ta lla tio n