CMS-1 CARBON MONOXIDE MONITOR
Page 6
© 2017 CLEMCO INDUSTRIES CORP.
www.clemcoindustries.com
Manual No. 23301, Rev. F
220-Volt AC:
These monitors are available from the
factory on special order. The only difference between
the 120-Volt and 220-Volt unit is the power cord.
2.4.2 AC to 12-Volt DC field conversion
Note: The following field conversion instructions to 12-
volt DC is for monitors with Serial Nos. 4446 and higher.
To convert monitors with serial numbers lower than 4446,
request manual No. 23301, Revision D or earlier.
The AC power cord provided with the monitor may be
used, using
black
as the positive. A user supplied DC, 2-
wire cord may be used, using red as positive. If a new
12-volt cord is used, splice the positive through the fuse,
and use the spade on the outlet of the fuse to connect to
J5 DC positive post, as shown Figure 4.
2.4.2.1
Make sure that all electrical power to the monitor
is locked-out and tagged-out.
2.4.2.2
Loosen the two case-cover screws and open the
case cover.
Some items removed or rotated for clarity
Figure 4
2.4.2.3
Remove the four faceplate screws, and carefully
remove the faceplate, being careful not to disconnect
any wires or tubing. NOTE: The screws on one side are
shorter than those on the other side, replace accordingly.
2.4.2.4
Remove the connector with red and black wires
from the plug on the circuit board, as shown in Figure 4.
If there is a chance the monitor will be converted back to
AC power, tie the wires out of the way. If the monitor is to
be permanently converted to 12-volts, pop off the clear
terminal cover and remove the wires from the terminal.
2.4.2.5
Disconnect the
white
and
black
wires from the
power supply lead-wires at the connectors, as shown in
Figure 4.
2.4.2.6
Plug the
black
wire onto the J5 (DC +) post at the
upper edge of the circuit board, as shown in Figure 4.
Plug the
white
wire onto the J6 (DC-) post.
2.4.2.7
Reposition the faceplate, making sure that all
internal air lines are free of interference, binding, or
kinks, and that all tube connections are secure. Tighten
the faceplate screws finger-tight to ensure they are
threading correctly, and then tighten to barely snug with
a screwdriver.
2.4.2.8
Close and secure the instrument case cover,
tightening the screws to a maximum of 20-inch lbs.
2.4.2.9
Remove the plug from the other end of the cord.
2.4.2.10
Attach a positive (+) terminal connector to the
end of the
black
wire and a negative (
-
) connector to the
end of the
white
wire. Clip the
green
wire.
Use any connectors that are compatible with a 12-
volt DC system. Make sure the connectors are
clearly marked positive (+) and negative (-). Attach
the positive connector to the wire leading to the DC+
post on the circuit board, and the negative
connector to the DC- post on the circuit board. The
monitor will not operate if wires are reversed.
2.5
Changing Alarm Trip-Point
2.5.1
The alarm trip-point is preset at 10 parts per
million (PPM), which is the maximum permissible
exposure limit (PEL) of CO for Grade-D breathing air in
the USA. Use the following instructions to change the
trip point to 5 PPM when required by local regulations.
2.5.2
Unplug the monitor from the power supply.
2.5.3
Open the case cover and insert a straightened
paper clip into the "ARM" port in the faceplate. While
The green ground wire may remain connected or
clipped when using the AC cord for DC
White wire to DC (J6)
J6 (DC )
J5 (DC+)
Green Ground Wire
Tie-off or
remove wires
Black wire to DC+ (J5)
Power Supply
Circuit Board
Fuse Assembly
Lead Wires
Connector Post
Remove Connector
Disconnect white
and black wire from
power supply leads
