Residential Gas Furnace Operation - HVAC.Amickracing

50A50 Flow Chart 1Indoor BlowerCheckPlace Thermostatin the on position.1ADoesindoor blowerrun at HEATspeed?YES1BReturnfan switch toAUTO position.NO1CIs LEDlight on controlON or flashing?(Door switchclosed)NO1D 1E 1FYES YES YES YESIs 24Vpresent atcontrol terminalsR & B/C?NOIs 24Vpresent atcontrol terminalsG & B/C?NOIs 120Vpresent atcontrol terminalsHEAT & CIRNEUTRAL?NOIndoor blowerfault. Repair orreplace. Checkoperation.Replace control.Check for operation.Replace control.Check for operation.Is 120Vpresent acrosscontrol terminalsLINE & LINENEUTRAL?Is 120Vpresent atcontrol terminalsXFMR & XFMRNEUTRAL?Is 120Vpresent acrossprimary of controltransformer?Is 24Vpresent acrosssecondary oftransformer?Repair wiring fromcontrol to thermostat.Check operation.NO1G 1H 1I 1J 1KYESYES YES YES YESNONONOIs 24Vpresent across12 pin connector pinsTH & TR on thecontrol?NOCorrect 120Vpower supply. Checkoperation.Correct 120Vpower supply. Checkoperation.Replacetransformer. Checkoperation.Repair wiringand/or plug connection.Check operation.CAUTION: If diagnostic indicator (LED) shows five (5) flashes,turn off gas supply at source before disconnecting electrical power.Failure to do so may result in personal injury or fire.51Note: Check diagnostic LED light flash rate through viewport in blower door before removing blower door!