74
SERVICING
S-314 CHECKING FLAME SENSOR
A flame sensing device is used in conjunction with the igni-
tion control module to prove combustion. If proof of flame is
not present the control will de-energize the gas valve and
"retry" for ignition or lockout.
WARNING
HIGH
VOLTAGE
D
ISCONNECT
ALL
POWER BEFORE SERVICING OR
INSTALLING THIS UNIT.
M
ULTIPLE POWER SOURCES MAY
BE PRESENT.
F
AILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE, PERSONAL INJURY OR DEATH.
Flame signal is continuously monitored by the IFC. The flame
rod, flame rod wire, and proper grounding are all critical to
proving the presence of flame. Because of the design of the
Honeywell flame proving system, reading flame signal with a
microamp meter will not provide reliable and consistent re-
sults and is therefore not a recommended practice. The IFC
has a built in warning (E6) if flame signal is approaching the
low threshold.
NOTE:
Contaminated fuel or combustion air can create a
nearly invisible coating on the flame sensor. This coating
works as an insulator causing a loss in the flame sense
signal. If this situation occurs the flame sensor must be
cleaned with steel wool.
