First, I will say this is the biggest piece of crap I have ever seen. It never stays on. First it light the igniter then the valve opens and flames appear. Error code indicates possible flame sensor failure. Replaced flame sensor. After that the door safety switch failed so I jumped it out. Then the igniter would light but no fire no error code just runs the exhaust fans for a minute. I took the connectors loose on the gas valve cleaned them up and now I am at square one. The igniter will light and flames come out and then the igniter goes out and a second after "whoof" out goes the flame. It does this 3 times then "ignition failure" one flash. One other thing I forgot it takes a long time after the exhaust fan comes for the igniter to light. I need this thing for one more winter any help is appreciated. It's getting cold at night!:confused:

Be sure the furnace, burners and gas valves are properly grounded. Second , if the polarity to the furnace is reversed you can have flame sensor issues.(120 volts and neutral wires reversed)

A problem that I have found after all else failed was a dirty evaporator coil. It acts like a dirty filter but adds in some other crazy stuff.

That sounds like a pain in the butt. I wondered about the filter but it seems to shut down before it would know the air is not moving enough. I took the filter out to flow more air while troubleshooting and it made no difference. I will have to look at the wiring again. I unhooked it last spring to rewire the basement and when I hooked it back up I had all these problems.

Your problem stills sounds like a flame sensor problem.


About the door switch. I think you said you bypassed it, if so you need to get a new one and get it installed. If you were to have a fire and the switch not operating the insurance company could give you lots of trouble.

Yea it was only when I was trouble shooting. The switch is bad so I will need a new one

I bought a new flame sensor. I wonder if it has a bad connection at the board

Just in case you do not have one here is a complete factory service manual for your unit. This manual covers many different Goodman furnaces so when using always look for your model number GMP under any of the diagnostic tables so you get the correct information.

Goodman makes a fine furnace that works well but many times these units are not professionally installed which can cause some problems down the road and worse yet they are not serviced by a HVAC professional which causes many other problems.

Hopefully this manual will help you locate your problem.

http://www.hvacpartsshop.com/Gmpe075-3%20Series.pdf (http://www.hvacpartsshop.com/Gmpe075-3%20Series.pdf)