Part # MCOSM06 Rev 1 (11/03/08) Page 31
Examples Of Unsatisfactory Pilot Flames.
APPEARANCE CAUSE
SMALL BLUE FLAME Check for lack of gas from:
•Cloggedoricelter
•Cloggedpilotlter
•Lowgassupplypressure
•Pilotadjustedattheminimum
LAZY YELLOW FLAME Check for lack of air from:
•Largeorice
•Dirtylintscreen,ifused
•Dirtyprimaryairopening,ifthereisone
•Pilotadjustedatminimum
WAVING BLUE FLAME
Check for:
•Excessivedraftatpilotlocations
•Recirculatingproductsofcombustion
NOISY LIFTING BLOWING FLAME
Check for:
•Highgaspressure
HARD SHARP FLAME
This ame is characteristic of manufactured gas
Check for:
•Highgaspressure
•Oricetoosmall
Control Module Flame Sensor Circuit.
The control module provides AC power to theigniter/sensor
that the pilot burner ame recties to a direct current. If the
ame signal back the control module is not at least 1.0 μA
DC, the system will lockout. The output of the ame sensing
circuit cannot be checked directly, so check the ame sensing
circuit indirectly by checking the ame sensing current from
the igniter/sensor to the control module as follows:
1. Connect a meter (DC micrometer scale) in a series with
the ame signal ground wire (Burner Ground Terminal).
Disconnect the ground wire at the control module. Connect
the red (positive) lead of the meter to the free end of the
ground wire. Connect the black (negative) meter lead to the
quick-connect ground terminal on the control module.
2. Restart the system and read the meter. The ame sensor
currant must be at least 1.0 μA, and the reading must be
steady. If the reading is below the value designated or the
reading is unsteady, check the pilot ame and electrical
connection. Also, replace the igniter/sensor if the ceramic
insulator is cracked.