Heat N Glo, Heatilator and Quadra-Fire Replacement NG IPI Pilot Assembly for Gas Stoves and Fireplaces. Part #4021-422 Original HHT Parts. No Generics. Replacement natural gas (NG) IPI pilot assembly for Hearth & Home gas stoves and fireplaces. This is an IPI pilot assembly, does not work with DSI, HSI or standing pilot units. Fits the following HHT gas fireplace models: Quadra-Fire Gas Fireplaces: QV36A-FB (Expression) - Pre February 2006 Heatilator Gas Fireplaces: BCBV36I - Pre serial # GA1551065 GCDC60i & GCDC60Li GCDC80i & GCDC80Li NB3630I NB3630MI NB3933I NB3933MI NB4236I NB4236IPLUS & NB4236ILPLUS NB4236MI NB4842I NB4842MI ND3630I & ND3630IL ND3630MI ND3933I & ND3933IL ND3933MI ND4236I & ND4236IL ND4236MI ND4842I & ND4842IL ND4842MI Heat & Glo Gas Fireplaces: 6000BE-IPI 6000TRI-IPI - After serial # 002324002 6000TR-OAK-IPI - After serial # 002324002 6000TRXI-IPI - Pre serial # 002952047 6000TV-OAK-IPI - After serial # 002324021 6000PLUS 8000CF-OAK-IPI - Pre serial # 002927628 8000TRD-IPI - After serial # 002324001 8000TR-OAK-IPI - Pre serial # 002927628 8000TVD-IPI - After serial # 002324001 8000TV-OAK-IPI - Pre serial # 002927628 BCBV36I - Pre serial # GA1551065 SOULSTICE SL-550TRS-IPI-D - Pre serial # 0021077066 SL-750TRS-IPI-D - Pre serial # 0021077066 Heat & Glo part # 4021-422 Replaces old part number 4021-025 OEM HHT part. May fit other models, check your owners manual for part numbers.