The 520899 will require a new wiring harness when used on older style wall furnaces.The 520896 and the 520896 wire harness kits are available as a separate parts and should be replaced at the same time as the ignition module.The 520899 will fits the following models:Dnyavent and Suburban Heater Models:DNV25NB25,000 BTUDirect Vent Wall FurnaceDNV25PB25,000 BTUDirect Vent Wall FurnaceDNV40NB 40,000 BTUDirect Vent Wall FurnaceDNV40PB 40,000 BTUDirect Vent Wall FurnaceSuburbanAire Models:SA25 25,000 BTUDirect Vent Wall FurnaceSA25N 25,000 BTUDirect Vent Wall FurnaceSA25P 25,000 BTUDirect Vent Wall FurnaceSA40 40,000 BTUDirect Vent Wall FurnaceSA40N 40,000 BTUDirect Vent Wall FurnaceSA40P 40,000 BTUDirect Vent Wall FurnaceWilliams Heater Models:Wall Furnace 2503532 25,000 BTU Window Wall FurnaceWall Furnace 4003532 40,000 BTU Window wall Furnace








