Furnace Direct

Hot Surface Igniter — 120V — manufacturer part number 21D64-2 .

What this part does
The hot surface igniter glows red-hot to light the gas burners when your furnace calls for heat. When it cracks or burns out, the furnace runs its inducer and blower but never lights, so you get air movement and no heat.

Replace this part if

Furnace runs but never ignites

You hear the inducer start, but no flame follows

Igniter glows dim orange instead of bright white-orange

Igniter is visibly cracked, chipped, or blistered white

Control board flashes an ignition-failure or lockout code

Specifications

Voltage
120V

Manufacturer Part Number
21D64-2

Condition
New

Sold By
Furnace Direct (Hamlin Mechanical LLC, MN Lic. #128688)

Install difficulty

Easy — about 20 minutes. Tools: 1/4" nut driver, screwdriver. Power off at the breaker: yes. Gas shutoff required: no.

Typical service life is 3-7 years. Most HVAC companies charge $250-350 to replace this part, including the service call.