Hi, I have a gibson m#KG6RK 072C-12A s#KGA021204267.natural gas.I've cleaned the flame sensor,that seem to work for a day with the furnace starting up on the first try.then I inspected further and found some wires that melted on the inducer\flu parts.so I cut out the bad part of the wire and reconnected them ,that seem to work for about a day.I did find a ground wire screwed to the inside of the furnace that wasn't hooked up to anything and it doesn't look like it was ever hooked up to anything.then I check to see if it had a good ground and the copper wire from the fuse box was grounding the switch box that connects to the furnace,so I'm assuming that the steel casing from the switch is grounding it properly.so sometimes the furnace tries five times to start and it doesn't,which gives me five flashing lights ,meaning (check ground).now when the furnace attemps to start I hear the inducer making a weird noise.I can't explain the noise other than it sounds like its vibrating.do you think my flame sensor is bad is there a way to check the resistance with a analog testing meter.I hope I left enough info any help will be greatly appreciated.thanks,greg

The ground referred to in the service legend is likely the ground path between the burner area and the circuit board/ignition module. Flame sensors rarely fail, but will certainly oxidize and require periodic cleaning - once every fall is usually adequate. If the circuit board/ignition module has metallic standoffs for mounting, they may be providing the ground. If this is the case with yours, make sure the screws are securely fastened.

Thanks for the reply.the circuit board/ign mod is connected to the furnace by plastic fastners.I have a red(hot) wire and a white (nue) wire coming in to the furnace but no ground wire I don't know how the board is getting a ground.other than maybe from the humidifier low voltage( converter?) which is tied to the gas pipe(grounded).then plugs in to the" hum" nue and "hum" hot on the board if that makes any sense.my light is now flashing 4 times meaning ign failure\bad ground.I would upload pics but can't seem to them on my PC right now.thanks for your help. p.s.s I hope I'm replying to you correctly

My light is now flashing 4 times meaning ign failure\bad ground.I don't think this has anything to do with the unit being grounded or ungrounded. The ignition module/circuit board must be grounded to the unit. If the ground connection is compromised, weak flame current will lead to ignition lockout. Check near the burner area for a ground wire leading to the module/board. Inspect for damage and/or poor connection.

Hi,there is a ground wire going to the ignition module.where should I go from here? Thanks,greg

The igniter had a resistance of 100 ohms,the roll out switches were 0 ohms, so I think there is nothing wrong there.