{"product_id":"626421r-nordyne-hot-surface-ignition-hsi-control-module","title":"626421R Nordyne Hot Surface Ignition (HSI) Control Module","description":"\u003ch1\u003e626421R Nordyne Hot Surface Ignition (HSI) Control Module\u003c\/h1\u003e\n\u003ch2\u003e\u003cspan style=\"background-color: rgb(255, 255, 0);\"\u003e\u003cstrong\u003eNormal Stock Item \u003c\/strong\u003e\u003c\/span\u003e\u003c\/h2\u003e\n\u003ch2\u003eProduct Overview\u003c\/h2\u003e\n\u003cp\u003e\u003cspan\u003e626421R is a genuine OEM Nordyne hot surface ignition control board offering 120\/240 VAC line-voltage switching for HSI elements, 24 VAC control inputs up to 250 mA, and integrated flame sensing with LED diagnostics. Backed by a 1-year warranty, it replaces legacy Nordyne and Miller HSI modules and ensures reliable ignition sequencing and lock-out protection in gas furnaces.\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003ch2\u003eCross-Reference Part Numbers\u003c\/h2\u003e\n\u003cdiv\u003e\n\u003cdiv\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eOEM Part Number\u003c\/th\u003e\n\u003cth\u003eNotes\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e626421R\u003c\/td\u003e\n\u003ctd\u003eCurrent OEM HSI control board (R revision)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e626421, 626-421\u003c\/td\u003e\n\u003ctd\u003eOriginal part numbers\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e626333, 6263330\u003c\/td\u003e\n\u003ctd\u003eSuperseded revisions\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e6264210, 626-4210\u003c\/td\u003e\n\u003ctd\u003eAlternate legacy revisions\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e626421B\u003c\/td\u003e\n\u003ctd\u003eOlder revision in the HSI control series\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1018, 1018-504\u003c\/td\u003e\n\u003ctd\u003eInternal hot surface ignition control series\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1706\u003c\/td\u003e\n\u003ctd\u003eInternal vendor part number for HSI control functions (hot surface ignition)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"pointer-events-none absolute inset-0 rounded-lg border border-stroke-300 dark:border-stroke-450\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003ch2\u003eCompatibility\u003c\/h2\u003e\n\u003cp\u003e\u003cspan\u003eThis HSI control board fits Nordyne and Nordyne Miller gas furnaces originally equipped with 626421-series ignition controls, including the Model 1018-2 and 621-series furnaces. It also serves as a direct replacement on OEM private-label units built on the same HSI platform. Always confirm compatibility against the unit’s data plate and service manual.\u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003ch2\u003eTechnician Notes\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eDe-energize all line-voltage and control-voltage power and shut off the gas supply before servicing.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eTag, photograph, or diagram existing wiring harnesses and control-board connections for accurate reassembly.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eWear an ESD wrist strap and handle the control board by its edges to prevent static damage.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eRemove the old board from its mounting bracket; inspect harness connectors for corrosion or wear.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eMount the new 626421R board onto the OEM bracket; ensure all harnesses seat fully into their keyed connectors.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eVerify 24 VAC between R and C terminals with a multimeter before powering up.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eObserve the board’s LED status indicators: a steady green light denotes normal operation; red flash codes indicate lock-out or ignition\/fault conditions—refer to the OEM service manual for code definitions.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eInitiate a heat call and confirm the sequence: inducer motor start, hot surface ignitor glow within ~15 seconds, gas valve actuation, and flame proving.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eIf ignition fails, count LED flashes, consult the manual, and test HSI element resistance (typically 70–100 Ω at room temperature) and 120 VAC output on the board’s HSI terminals.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv class=\"relative pb-6 w-full after:border-b after:border-stroke-300 after:w-full after:absolute after:mt-3\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003ch2\u003eAdditional Resources\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eDownloadable OEM wiring diagram and installation\/service manual (PDF)\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003ePrintable hot surface ignition control cross-reference cheat sheet\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cspan\u003eStep-by-step video tutorial: Nordyne HSI control replacement\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- rlb --\u003e\n\u003cp\u003eNordyne hot surface ignition control. \u003cbr\u003e\u003cbr\u003eReplaces 626333, 6263330, 626-421, 626421, 626-4210, 6264210.\u003cbr\u003e\u003cbr\u003e\u003cspan style=\"color: #ff0000;\" color=\"#FF0000\"\u003eCONTROL LIGHT STATUS\u003c\/span\u003e\u003cbr\u003e\u003cspan style=\"text-decoration: underline;\"\u003eRED\u003c\/span\u003e\u003cbr\u003e1 Flash - the control is in lock-out because the inducer pressure switch is or was stuck closed. \u003cbr\u003e2 Flashes - the control is in lockout because the signal was not received by the control that the inducer pressure switch had closed within the time.\u003cbr\u003e3 Flashes - the control is in lockout because a failed ignition attempt, a gas valve error or a false flame sensed during the warm up period. If false flame has been sensed, the control will return to normal operation, and repeat ignition sequence when the false flame is not present.\u003cbr\u003e4 Flashes - the control is in lockout due to a failure within the control board. Replace or repair the board.\u003c\/p\u003e","brand":"Quinn","offers":[{"title":"Default Title","offer_id":45563751039042,"sku":"626421R","price":247.04,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1071\/8320\/products\/images_97.jpg?v=1739538927","url":"https:\/\/hvacpartstore.com\/products\/626421r-nordyne-hot-surface-ignition-hsi-control-module","provider":"HVACpartstore","version":"1.0","type":"link"}