50A52 Flow Chart 3 - American Standard *UD Series Operation Manual

50A52 Flow Chart 3

Main Burner Ignition
Check, Inducer On
3A
YES
Does
Ignitor Glow?
NO
Is 24 VAC Present
at "GC" and "FSI"
Terminals?
YES
Is 120 VAC
Line Voltage Present at
Ignitor Hot and Ignitor
Neutral Terminals?
YES
YES
Is 120 VAC Present
at Ignitor Polarized Plug?
(HSI Unplugged)
NO
Check Ignitor
and Wiring Harness
NO
Sensor Open,
Check Wiring,
Replace Switch
NO
Replace
Control
Replace
Ignitor
3B
Does
Burner
Ignite?
NO
Is Gas
Present at
Burner?
NO
Is
24 VAC Present
at Control "GC" and
"GR" Terminals During
Ignitor Warm Up
Period?
YES
Is 24 VAC
(10VAC if sensor
switches to Hot Position)
Present at Gas Valve Common
(BL) and Redundant Coil
(OR) During Ignitor
Warm Up
Period?
YES
Is 24 VAC
Present at Gas
Valve Main (RD) and
Common (BL) and at Gas
Valve EQSO (BR) and Common
(BL) After Ignitor is
De-energized?
NO
Check Radiant
Sensor Operation
63
YES
Chart 4
YES Check Ignitor Position
and Gas Pressure.
Note: Air in Gas
Line Must Be Purged.
NO
Replace
Control
NO
Check
Wiring
YES
Replace
Gas Valve
Chart 4