35-3010A-09 Sample-Draw Detector • 15
8.
If necessary, use a small flat-blade screwdriver to adjust the oxygen transmitter’s zero
pot until the voltmeter reading is 434 mV (± 2 mV).
9.
Close the housing door.
Operation
Normal Operation
During normal operation, the Pilot LED will be on and the flowmeter will indicate about
1.2 SCFH. The current gas readings will be indicated at the controller. See the controller’s
operator’s manual for a description of the reading indications.
Low Flow Alarm
If the flowrate falls below 0.6 SCFH (±0.2 SCFH), then the sample draw detector will
initiate a low flow alarm. In a low flow alarm the Fail LED will turn on and the pump will
shut off. If a low flow alarm occurs, press the pump reset switch for about 2 seconds to
restart the pump and turn off the Fail LED. If the condition continues, find the cause of the
reduced flow, correct it, and restart the pump with the pump reset switch. A flow
reduction can be caused by a flow blockage, a leak in the flow system, a malfunctioning
pressure switch, or a malfunctioning pump.
NOTE:
There is no flow fail indication for the CH
4
and oxygen channels on the
35-3010A-09.
Maintenance
This section describes maintenance procedures. It includes preventive maintenance
procedures. This section also includes procedures to troubleshoot the sample-draw
detector, replace components of the sample-draw detector, and adjust the low flow
setting.
Preventive Maintenance
This section describes a preventive maintenance schedule to ensure the optimum
performance of the sample-draw detector. It includes daily, monthly, and quarterly
procedures.
Daily
1.
Verify that the pilot light is on.
2.
Verify that the flowmeter indicates a flow rate of approximately 1.2 SCFH.
If necessary use the bypass valve or flow adjust potentiometer to adjust the flow rate
to 1.2 SCFH.
3.
Verify a reading of 0% volume for the IR CH
4
channel (100 mV at the CH
4
transmitter
test points) and 20.9% for the oxygen channel (434 mV at the oxygen transmitter test
points). Investigate significant changes in the reading.
