Newer Ruud Professional units use electronic ignition (hot surface or spark). When failed, throws Code 11 or pilot equivalent.
Two types
- Spark ignition: high-voltage spark across electrode gap
- Hot surface ignition: silicon carbide rod heats to 1500°F+
Confirm failure
- Turn off gas
- Trigger ignition attempt
- Spark igniter: visible blue spark in dark room
- Hot surface: should glow orange after 30 seconds
- No spark/glow = igniter failed
Replacement (DIY-friendly with care)
- Off gas; off 120V power
- Remove burner cover
- Disconnect igniter cable
- Unscrew/unclip igniter
- Install new (handle ceramic carefully)
- Connect cable; restore gas and power
Cost
- Spark igniter: $40-80
- Hot surface igniter: $50-100
Bottom line
Visual confirmation before ordering. DIY-replaceable with care for ceramics.