Sierra Monitor Corporation 5000 Cover Plate - Carbon Monoxide Module, SERVICE Page

SMC sierra monitor corporation Sentry Instruction Manual - Version 6

7.7 CARBON MONOXIDE MODULE (5100-04)

7.7.1 DESCRIPTION

The Carbon Monoxide Module includes the sensor and electronic assembly installed in an explosion proof housing.

The sensor screws into one hub of the enclosure and plugs into the bottom electronics card via a six pin connector. Cabling from the controller connects to a three pin spring loaded terminal strip.

7.7.2 TROUBLE ANALYSIS

Electrical adjustment, or replacement of the sensor will be necessary under the following conditions:

•Controller displays the following error messages

SENSOR FAILURE

LOW SENSITIVITY

•False readings or alarms are received due to sensor inaccuracy.

Warning: During sensor adjustments the
	Figure 7-8
concentration reading on the controller will be
	Cover Plate - Carbon Monoxide Module
inaccurate and alarm level concentrations may be
displayed. If false activation of the alarm relays
will cause a problem disconnect the relay wiring

prior to adjustment or turn the module off using the		• 1 ppm CO = 0.004 VDC.
"Change Module" mode.		• 100 ppm CO = 0.40 VDC.
	Note	• 250 ppm CO = 1.00 VDC.
	Although all the necessary data can be collected with a
	voltmeter at the sensor module, some helpful information
	can be displayed on the controller or printed. See	7.7.3.2 SENSOR REPLACEMENT
	diagnostic codes 0004 and 0008 in Appendix C.	The carbon monoxide sensor should be replaced when it
7.7.3 ADJUSTMENT PROCEDURE		can no longer be calibrated correctly.	Generally this is
Prior to reading voltages and making adjustments perform		every twenty four to thirty months.
a visual inspection to confirm that there are no physical		The "SENSOR FAILURE" message for Carbon
problems such as water in the electronics enclosure,		Monoxide sensors does not indicate a specific failure of
wiring damage or corrosion.		the sensor but indicates that the sensor is not correctly
Use Figure 7-8 to locate test points during the following		connected to the electronics. If this	message appears

procedures.	check that the sensor harness is correctly installed to the
	connector on the bottom electronics board.

7.7.3.1 SIGNAL ADJUSTMENT

It is unlikely that any electrical adjustment will be required except when a new sensor is installed.

To make the electrical adjustment connect a voltmeter to SIGNAL OUT (pos) and GND (ground) and use SENSITIVITY ADJ potentiometer to adjust the voltage based on the following:

SERVICE

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