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d. Check gas pressure coming to the gas
valve.
e. Replace the gas valve if the main burner does
not come on under the above conditions.
Pilot Will Not Light or Goes Out
a. Check the incoming gas pressure.
b. Check for the proper pilot orifi ce. See the
nameplate SPECIFICATION.
c. Check for proper pilot fl ame adjustment. See
“BURNER ADJUSTMENTS.”
d. Check the thermocouple millivoltage.
• Millivoltage should read between 18 and 30
mv.
Control Module Status Indicators - M1M Series
Control Status
The Red LED labeled “STATUS” is provided to indicate system faults.
Steady ON:
Control OK
Steady OFF:
No power
Rapid fl ash:
False fl ame or internal control fault
One fl ash:
Limit switch is open
Two fl ashes:
Pressure switch is open
Three fl ashes:
Pressure switch is stuck closed
Four fl ashes:
Lockout due to failed ignition
Five fl ashes:
L1 neutral reversed or L1 voltage
not present on L1
Flame Status
A Yellow LED labeled “Flame” is provided to indicate fl ame status. When fl ame is sensed, the
fl ame LED is lit. If fl ame sense is weak, yellow LED will fl ash.
Control Module Status Indicator - M1S* Series
The indicator light(s) on the oil primary control provides lockout, recycle
and cad cell indications as follows:
• If the closed millivolt reading is not between
18 and 30 mv., the gas valve electromagnet
may be defective. Replace the gas valve if
necessary.
e. Be sure the pilot shield is in place.
f. Check for gas leaks in the pilot line or the pilot
assembly.
g. Check the fl ue assembly to make sure all
connections are tight.
h. See the FURNACE START-UP procedure for
lighting details.
Control Module Status Indicator - M1B
a. One fl ash-the control is in lock-out because the inducer centrifu gal switch is or was
stuck closed.
b. Two fl ashes-the control is in lockout because the signal was not received by the control
that the inducer centrifugal switch had closed within the time.
c. Three fl ashes-the control is in lockout because a failed ignition attempt, a gas valve error,
or a false fl ame sensed during the warm up period. If false fl ame has been sensed, the
control will return to normal operation, and repeat ignition sequence when the false fl ame
is not present.
d. Four fl ashes-the control is in lockout due to a failure within the control board.
Honeywell R7184 Control:
Indicator LED
Status
On
Cad cell is sensing fl ame (could be fl ame or stray light)
Off
Cad cell is not sensing fl ame
Flashing (1/2 sec. on, 1/2 sec. off)
Lockout/Restricted Lockout
Flashing (2 sec. on, 2 sec. off)
Recycle
Beckett 7505 Control:
Light Color
On Continuously
Flashing
Red
Restricted (Hard) Lockout
Soft Lockout
Green
Cad cell is sensing fl ame (could be fl ame or stray light)
Recycle
Yellow
Pump Prime mode or Reset button currently held for 15+ sec.
Cad cell resistance
(see table 10)