
770 
Carbon Monoxide Monitor
The Value Leader
TM
www.tpi-thevalueleader.com

770 Features and Push Buttons
CARBON MONOXIDE - SINGLE GAS MONITOR
Product Description
The 770 CO Single Gas Monitor is a state-of- the-art 
Carbon Monoxide Instrument designed to measure Carbon 
Monoxide in ambient air and to perform a carbon monoxide 
build up test . It has a measurement range of 0 to 999 ppm 
(parts per million) and displays the readings in 1ppm increments. The unit features a personal audible and visual 
alarm, which is factory set at 30ppm CO but can be 
changed in the field to keep current with government 
legislation. Other features include: maximum reading hold, 
elapsed time and manual zero. The audible alarm may be 
switched on and off as required. Battery changing is made 
easy by use of a simple slide off battery compartment 
cover.
The detector uses an advanced electrochemical sensor that 
measures Carbon Monoxide and should not be used for any 
other purpose. 
Note:  This instrument meets the requirements of 
BS 7967 
Calibration is required every 12 months
Red Warning 
LED
SEL Push 
Button
Green Power 
LED
LCD Display
ON/OFF 
Push Button
Mode Push 
Button
Sensor opening 
on back of case
Battery compartment access on 
back housing

Specifications
Size: 
Weight: 
Sensor:         2 year life Electrochemical 
Range:         0 to 999ppm ( parts per million )  
Accuracy:       ± 3 ppm or 5% whichever is the 
greater. 
Response Time:  90% of reading within 60 seconds. 
Temperature: 
Batteries:       2 x 1.5v size AA Alkaline . 
Operating Time:
On/Off Press the green power switch in order to
turn the instrument on.  All segments will 
be displayed for approximately 2 seconds. 
The screen will then display CO in ppm and 
the reading will rapidly count down to zero 
as the instrument stabilizes. The green 
power on indicator will be illuminated. To 
switch off, press the green power switch 
twice in quick succession.
Note: Always switch the instrument on in 
outside ambient air.
Mode Pressing the Mode key scrolls through the
functions: Record Maximum Reading, 
Elapsed Time, Alarm Setting, Audible Alarm,
CO display. 
Record Maximum Readings - displays the 
maximum CO reading in ppm since power 
on.  
Elapsed Time - displays, in hours and minutes, the time elapsed since power on. 
Maximum reading is 99 hours 59 minutes ( 
99:59 ) 
Alarm Setting - displays the value that the 
personal audible and visual alarm is set at. 
Alarm is factory set at 30ppm CO. Audible 
Alarm - In this mode the 
Audible Alarm can be switched on and off 
by pressing the SEL button.
SEL Manual Zero - The instrument performs an
auto zero at power on. If the instrument 
does not zero, a manual zero may be performed. With the CO display screen selected 
press and hold the SEL key for 2 seconds 
until a short beep is heard. The screen will 
display some changing symbols and after 5 
seconds the instrument will zero and other 
beep will be heard.  
Changing Alarm Setting - The 770 is set at 
the factory to 30ppm alarm level. With the 
instrument switched off press the On/Off key

and the SEL key at the same time until 'Set 
1' is displayed. Press the On/Off key and the 
set alarm level will be displayed. The Mode 
key will increase the set alarm level and the 
SEL key will decrease it. Each key press will 
change the alarm level reading by 1 ppm. 
When the desired alarm level has been 
selected press the On/Off key to set the level 
and 'End' will flash on the screen. Press 
On/Off to return to the CO screen.
Other Features
· When the audible alarm is switched off a
small 'double speaker' symbol will be displayed at the bottom left of the LCD. When 
the alarm setting is exceeded a 'warning' 
symbol is displayed at the bottom center of 
the screen and the red warning indicator is 
illuminated. As the battery level approaches 
2 volts a 'BAT' warning symbol is displayed 
to indicate low battery level. When the battery level gets too low the unit will automatically switch off.
Battery Replacement
Locate the battery compartment on the rear 
of the unit. Place thumb on the battery compartment cover and press and slide down 
cover to remove. Replace batteries and slide 
cover back into place.
Warranty
Your CO detector is warranted to be free 
from defects for a period of 3 years. The 
Electrochemical sensor is guaranteed for 2 
years. This warranty covers normal use and 
does not over damage which occurs from 
tampering, accident, misuse or neglect. 
Instruments out of warranty will be repaired 
for a service charge. Return the unit postpaid and insured to:
Test Products International, Inc.
9615 SW Allen Blvd. 
Beaverton OR 97005
(503) 520 9197
This warranty gives you specific legal rights and 
you may also have other right which vary from 
state to state.

Copyright © 2001, Test Products International, Inc
The Value Leader
TM
www.tpi-thevalueleader.com
Test Products International, Inc.
9615 SW Allen Blvd
Beaverton, OR 97005-4814 USA
770 Instruction Manual