User Manual
10 • 65-2405RKSS Combustible Gas Transmitter
Troubleshooting
The troubleshooting guide describes symptoms, probable causes, and recommended 
action for problems you may encounter with the combustible gas transmitter.
NOTE: This troubleshooting guide describes transmitter problems only. See the 
controller operator’s manual for problems you may encounter with the 
controller.
Replacing Components of the Combustible Gas Transmitter
This section includes procedures to replace the combustible gas detector and amplifier.
Replacing the Combustible Gas Detector
1. Turn off power to the controller.
2. Place the controller’s power switch in the OFF position.
3. Remove the junction box cover.
4. Remove the detector terminal strip from its socket.
5. Disconnect the detector leads from the detector terminal strip. Note the position of the 
color-coded leads as you remove them.
6. Unscrew the detector from the junction box.
7. Guide the detector leads of the replacement detector through the bottom conduit hub 
of the junction box, then screw the mounting threads of the detector into the conduit 
Table 2:Troubleshooting the Combustible Gas Transmitter
Condition Symptom(s) Probable Causes Recommended Action
Fail Condition • Controller indicates a 
fail condition.
• The transmitter wiring 
is disconnected or 
misconnected.
• The transmitter’s zero 
reading is low enough 
to cause a fail 
condition.
• The transmitter is 
malfunctioning.
1. Verify that the transmitter wiring is 
correct and secure.
2. Calibrate the transmitter.
3. If the fail condition continues, replace 
the detector.
4. If the fail condition continues, contact 
RKI for further instruction.
Slow or No 
Response/
Difficult or 
Unable to 
Calibrate
• Transmitter responds 
slowly or does not 
respond to response 
test.
• Unable to accurately 
set the zero or 
response reading 
during calibration.
• Transmitter requires 
frequent calibration.
Note: Under “normal” 
circumstances, the 
transmitter requires 
calibration once every 3 
months.
Some applications 
may require a more 
frequent calibration 
schedule.
• The calibration cylinder 
is low, out-dated, or 
defective.
• The calibration gas 
flow rate is too low.
• The calibration gas is 
not an appropriate 
concentration.
• The transmitter is 
malfunctioning.
1. Verify that the calibration cylinder 
contains an adequate supply of a 
fresh test sample.
2. Verify that the regulator used for 
calibration is a 0.5 LPM regulator.
3. Verify that the calibration gas 
concentration is appropriate for the 
transmitter. The concentration should 
be in the detection range, preferably 
about half of the detection range.
4. If the calibration/response difficulties 
continue, replace the detector.
5. If the calibration/response difficulties 
continue, contact RKI for further 
instruction.










