Intermittent ignition system troubleshooting chart – Crown Boiler BWF061 User Manual
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Does
spark stop
when pilot
lights?
24 volts
across
terminals 2&3
at S8670?
Spark
across
ignitor/sensor
gap?
Y
Can you
hear
sparking?
* Defective 
S8670 
module
* Break in 
spark cable 
insulation
* Break in pilot 
porcelain
* Incorrect 
pilot spark gap
* Loose 
connection in 
spark cable
* Loose 
ground 
connection
N
Pilot
lights?
Y
N
N
* Defective 
S8670 module
24 volts
across PV &
MV/PV at gas
valve?
* Defective EI 
wiring 
harness.
N
* Loose connection 
in ignition cable or 
ground wire
* Pilot electrode 
porcelain cracked
* Pilot flame not 
covering gap 
between electrode 
and grounding 
strap
* Low gas pressure 
at gas valve inlet
* Defective S8670 
module
Main
burner
lights?
N
Y
24VAC
across
terminals 1&2
on S8670?
Y
N
N
* Defective
S8670 
module
24 volts
between MV &
MV/PV on gas
valve?
* Defective 
gas valve
*Defective EI 
harness
END
START
(24 volts is present across 5 and 6 on S8670, 30-50
second prepurge period has passed, but main
burners do not light)
N
Y
Y
N
Y
Y
Y
* Low line pressure
* Plugged, kinked or leaking 
pilot tubing
* Plugged pilot orifice
* Gas line not purged of air
* Defective pilot assembly
* Defective gas valve
Intermittent Ignition System Troubleshooting Chart