Troubleshooting Flame Scanners Potentially Damaged by Water
FILED UNDER: BMU, BurnersSymptom
Flame scanner stopped working all of sudden on a burner with FGR. Upon first firing the boilers from a cold state, heavy condensation would pass through the FGR valve and blow up through the scanner’s sight tube/mount.
Steps to Troubleshoot
· Be sure burner is off. Leave panel powered.
· Remove cable from scanner and remove scanner from burner.
· Inspect scanner lens for build-up. You may also notice water bulbs on the other side of the lens.
· If scanner is a UVSC, you can unscrew bottom portion of housing to check for presence of water inside the aluminum. DO NOT unscrew lens holder to expose internal electronics.
· Inspect all wiring from scanner cable back to panel to ensure power is getting to scanner as well as “Flame On” contact wire(s) are properly terminated.
· Re-connect cable to scanner.
· With scanner powered, place a flame (either from lighter or torch) in scanner’s line of sight.
· Look to see if “Flame Status” & “Flame Relay” LED’s on scanner have illuminated.
· Look to see if flame safeguard has registered a flame signal.
· If neither or only one of the above indications are present, the scanner is not working properly and should be sent back to Preferred for evaluation. Contact Order Entry Dept. for RMA form.
Resolution
When FGR is utilized, if possible, any flame scanners should be aimed downward to avoid condensate collection in the flame scanner.
If it is not possible to aim a flame scanner downward, then clean purge air must be used. This air cannot be mixed air/fgr from the windbox. This purge air needs to be at least 2 PSIG.
