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Quick Start
1. Install 9V battery located in the bat-
tery compartment.
2. Press ON/OFF for 1 second to power
on the SCM4 in a nominal CO envi-
ronment such as outdoors.
Note: 10 second warm up ensues.
3. If necessary, press ZERO while out-
doors to set the ambient CO ppm.
4. Carbon monoxide (CO) above nomi-
nal levels will be displayed in parts
per million (ppm.)
5. Press ON/OFF for 1 second to power
off.
Certifications
C-Tick (N22675)
CE
WEEE
RoHS Compliant
Description
The SCM4 standalone carbon
monoxide detector measures carbon
monoxide in parts per million (ppm.)
It is intended to measure levels
of CO in still, ambient air. The most
practical application of the SCM4 is
to determine if the indoor CO levels
are higher than outdoor levels and to
determine the source. In many cases,
it can help locate a source of CO.
The SCM4 uses a fast reacting,
electrochemical sensor that does not
consume chemicals and can easily be
replaced in the field if needed. Sensor
life is primarily determined by the type
of exposure.
Precautions
1. Do not measure gas engine exhaust
or other high CO or highly contami-
nated gases. High levels of CO and
other contaminants can ruin the
sensor and be a health hazard.
2. Do not take readings directly in
stream of air at register or in a flue.
3. Allow enough time for SCM4 to reach
ambient temperature and %RH.
4. The sensor has built-in permanent
non-replaceable filter to filter out
trace concentrations of SO
2
, NO
2
,
and most hydrocarbons. If exposed
to high concentrations of harmful
chemicals such as methanol, etha-
nol, or dirt, the filter can deteriorate
and/or impede diffusion of CO to
the sensor.
Fieldpiece
Carbon Monoxide
Detector
OPERATOR'S
MANUAL
Model
SCM4
Display
Controls
SCM4
ON/OFF
MUTE
ZERO
MAX
Carbon
Monoxide
Detector
Measures
CO in PPM.
PRESS FOR
1 SECOND
AUTO-OFF
BATT CHECK
Hold for one second to toggle power.
SCM4
ON/OFF
MUTE
ZERO
MAX
Carbon
Monoxide
Detector
Measures
CO in PPM.
PRESS FOR
1 SECOND
AUTO-OFF
BATT CHECK
Cancel out any ambient
nominal CO. (See Zero Set.)
SCM4
ON/OFF
MUTE
ZERO
MAX
Carbon
Monoxide
Detector
Measures
CO in PPM.
PRESS FOR
1 SECOND
AUTO-OFF
BATT CHECK
Toggle backlight on display.
SCM4
ON/OFF
MUTE
ZERO
MAX
Carbon
Monoxide
Detector
Measures
CO in PPM.
PRESS FOR
1 SECOND
AUTO-OFF
BATT CHECK
Mute the beep. Hold for one second to
check % battery remaining.
(Hold while powering ON to disable APO.)
SCM4
ON/OFF
MUTE
ZERO
MAX
Carbon
Monoxide
Detector
Measures
CO in PPM.
PRESS FOR
1 SECOND
AUTO-OFF
BATT CHECK
Show maximum measurement.
How to Use
"Walk Around" Test
The SCM4 responds almost instantly
to changes in CO levels in the air. If
you see a difference in CO levels from
outside to inside, you need to find the
source of the CO. Walk around and
watch the display.
By constantly going towards the
area of higher concentration, you can
determine the source of the CO.
Persistent sources of CO, such
as malfunctioning combustion
equipment in occupied spaces, must
be serviced immediately. These can be
life threatening.
When searching for sources of CO,
make sure that you never put yourself
or anyone else in danger of excessive
exposure to CO. Overexposure to CO
can have long-term health effects and
can be fatal.
Zero Set
As needed, set the reading to zero in
a known zero CO atmosphere and in a
temperature similar to the sample air
to be tested. Zero only when ambient
air is within specifications and probe
is in equilibrium (temperature and
relative humidity) with ambient.
To zero, hold the ZERO button
for one second or until “ZERO” is
displayed. (Note: For safety reasons
the SCM4 will not zero if reading is
above 5ppm.)
SCM4
ON/OFF
MUTE
ZERO
MAX
Carbon
Monoxide
Detector
Measures
CO in PPM.
PRESS FOR
1 SECOND
AUTO-OFF
BATT CHECK
Specifications
Sensor Type
: Electrochemical (specific to CO)
Sensor Calibration
: Factory calibrated @ 205
ppm CO
Range
: 0 to 1000 ppm;
0 to 2000 ppm (less than 5 minute exposure
time)
Initial Accuracy
: @ 73°F±9°F, <75% R.H.
0-15ppm ±5% reading ±1 ppm after zeroing
16-35ppm ±5% reading ±2 ppm after zeroing
36-1000ppm ±5% reading ±5ppm after
zeroing
Long Term Drift
: less than 5% per year
(depending on use)
CO Air Sample Temperature Range
: 32 to
105°F
Operating Environment
: 32 to 122°F (0 to
50°C);
15 to 90% R.H., non-condensing
Storage Environment
: 32 to 68°F (0 to 20°C) at
<80% R.H. with battery removed from meter.
Battery
: 9V.
Battery Life
: 150 hours typical alkaline.
Auto Power Off
: After 15 minutes.
Storage
To maintain sensor integrity, do
not store in areas containing solvent
vapors. This includes aerosols such
as air-freshener, wax polish, window
cleaner, and all organic solvents.
SCM4
ON/OFF
MUTE
ZERO
MAX
Carbon
Monoxide
Detector
Measures
CO in PPM.
PRESS FOR
1 SECOND
AUTO-OFF
BATT CHECK
Auto Power Off
(APO) Enabled
Real Time CO ppm
Measurement
Maximum CO ppm
Measurement
Instrument Muted
Low Battery
CAUTION
!
Do not take measurements directly at a tailpipe, or at a flue. See "Precautions."
Do not rely solely on a carbon monoxide measurement to determine if a heat exchanger is bad. See “CO
Detectors and Cracked Heat Exchangers" section.
The majority of toxic gas sensors contain sulphuric acid electrolyte and the chemical hazard is mainly related
to the corrosive nature of this compound. These sensors also contain platinum, ruthenium, gold, silver, carbon
some of which are toxic.
Any skin or eye contact with the contents of these sensors should be washed immediately with copious amount
of water. Obtain medical advice.
Electrochemical gas sensors are sealed units containing an aqueous electrolyte and a combination of other
substances as detailed above. Provided these sensors are used only for their intended application they do not
represent a chemical hazard.
The sensors must not be exposed to temperatures outside the range -50°C to 60°C. Toxic gas sensors should
not be exposed to organic vapours which may cause physical damage to the body of the sensor, for example 1,
2 dichloroethane.
Should any sensor be so severely damaged that leakage of the contents occurs then the following procedures
should be adopted.
a. Avoid skin contact with any liquid or internal component through use of protective gloves.
b. Disconnect sensor if it is attached to any equipment.
c. Use copious amounts of clean water to wash away any spilt liquid. This is particularly important in
equipment where the sensor involved contains sulfuric acid or phosphoric acid because of the corrosive
nature of these electrolytes.
WARNING
!
Extended exposure to even relatively low carbon monoxide concentrations can be hazardous to human health.
Evacuate areas of significant CO concentration immediately. See the CO Exposure Effects section of this manual.
