This part is out of stock right now, so it cannot be added to the cart.
This part heats up to light the fuel. If the igniter is cracked, damaged, or worn out, the appliance may attempt to start but will never light.
Specifications
- Part number: 100110899
- Brand: Ao Smith Water Heater
- Part type: Igniter
- Gas type: Natural Gas & Propane
- Height: 4.9 in / 12.45 cm
- Length: 1.75"
- Material: n/a
- Width: 10.8 in / 27.43 cm
- Volts: must be the same, often 120 V
- Material: silicon carbide or nitride, as listed
- Shape and mount: must fit the same bracket
From the maker's and parts sellers' listings for this number. Compare them with the label on your old part.
How the Igniter Works
An igniter is an essential component in gas-fired heating equipment. When the system calls for heat, electrical current flows through the element.
The element gets hot enough to ignite the fuel flowing from the burner assembly. If the component breaks or burns out, the burner will not catch fire, leaving the water heater unable to produce hot water.
Understanding the Part Specs
Matching the exact dimensions and fuel compatibility is important when replacing an ignition component. The recorded specs for number 100110899 include:
- Gas type: Natural Gas & Propane
- Height: 4.9 in / 12.45 cm
- Length: 1.75"
- Width: 10.8 in / 27.43 cm
- Material: n/a
Signs of Failure and Safe Replacement
A failed igniter typically prevents the burner from lighting. You might hear the equipment click or attempt to cycle, but no flame appears. A visible crack across the element is another clear sign of failure.
Follow basic precautions if you decide to inspect or swap the component yourself:
- Turn off power to the water heater at the breaker and shut off the main gas supply line.
- Take a clear photo of the wiring setup before disconnecting anything.
- Carefully remove the mounting screws holding the old bracket in place.
- Handle the new igniter only by its base or bracket. Never touch the element surface with your fingers.
- Secure the part to the burner assembly and connect the wires to the same spots as the original part.
Read your old part
- Look at the label, stamped stamping, or paperwork on your old igniter assembly.
- Verify that the part number matches 100110899.
- Confirm your system uses Natural Gas & Propane fuel.
- Check that the bracket design, mounting holes, and element shape align with your existing assembly.
- Make sure the voltage requirement matches your equipment, as voltage ratings must be the same.
When to call a pro
Hire a licensed HVAC technician or professional plumber if you are not sure you can complete the repair safely. Always call a licensed technician for work involving gas lines, gas pressure adjustments, or complex electrical wiring.
Questions
Can I touch the igniter element with my hands?
No, you should never touch the element with bare fingers. Igniters are brittle, and skin oil left on the surface can shorten the life of the part.
What fuel types work with part 100110899?
This part is rated for both Natural Gas & Propane systems.
What should I do if I smell gas during replacement?
Do not touch any electrical switch. Leave your home immediately and call your gas company from outside.
Why does voltage matter for an igniter?
Voltage must be the same between the old and new part. Most furnace and appliance hot surface igniters use 120 V, while some use 80 V, and they are not interchangeable.
Related part numbers
- 100112456Igniter, A.O. SmithSame brand and type
- 100271888Igniter Guide, A.O. SmithSame brand and type
- 1009524Igniter Reference Guide, HeilSame part type
- 100109908Flame Sensor, A.O. SmithSame brand
- 100191120Igniter, A.O. SmithSame part type
- 18187Ignitor Cable Reference Guide, UltrafryerSame part type
- 100113151Water Heater 100113151 Flame Sensor Guide, A.O. SmithSame brand
- 100108267Thermocouple, A.O. SmithSame brand
Browse: A.O. Smith part numbers · Hot surface igniters by part number
All part numbers · Part number replacements · Shop igniters · Repair guides
Brand names and part numbers identify the part and show fit. HVAC Fitter is not affiliated with, authorized by, or endorsed by any equipment maker. If you are not sure a repair is safe for you, call a licensed HVAC technician.