Furnace Kicking on then off after 4 seconds

I don't know a whole lot about furnaces but here we go. Goodman furnace.

The fan on the furnace is going, and I can hear the gas basically turn on but it kicks off after 4 seconds. Initially I replaced my filter and it seemed to work. But it's still doing it, but the weird part is sometimes the furnace stays on. Other times it just keeps kicking on and off.

Anyways, I opened it up, theres a green light and a red light on the circuit board. The red just stays red. The green light will turn on, blink 8 times and turn off. I googled that and it says ignitor.

But after looking around some more at what could be causing it, there is this little container attached to the outside of the furnace with these 2 little hoses or whatever. That container is full. Then from that container is a pvc pipe going down to the floor, and then over into a bigger container. This has hoses coming out of it that go to my downstairs utility sink. I can see liquid in there too but its not full. The design doesn't seem proper.

Anyways the container on the furnace is full of liquid, and for some reason its not spilling over into the pipe. I'm thinking because of that furnace won't ignite. But now I'm worried about carbon monoxide in that liquid etc. I can't get the furnace repair in until sometime Monday. The house gets cool at times but then it will warm back up because like I said the furnace does run at times. So I'm doing ok, but is there anything unsafe to worry about such as carbon monoxide etc.

Thanks for any help you may have!

 

Welcome to the forums.

You didn't mention the age of the unit or model number but with condensing furnaces.... water in the tubing can be normal.

Your problem sounds like a dirty flame sensor rod. It'll be mounted near the burner, would stick into the flame, be connected with one wire and be mounted with one screw. You can remove the screw and disconnect the wire. Polish the metal rod with steel wool or one of those green scotchbrite pads.

The picture below is a representation of what a flame sensor looks like.

 

I'm not sure the model number but it is 6 years old. I just moved into the house in July, previous owners had this installed in 08.

Anyways, I could take it off and see if it would do the trick. So whats the best way of going about this? Turn off the switch to the furnace, wait how long until I take it off? Can I use like an SoS pad or something? And just polish the metal part of it? Thanks for you help!

 

You can turn the power off and remove the rod right away. SoS pad will work fine. You just want to remove any residue from that rod and make it shiny. Nothing critical in the process.

 

So I took off the sensor, a stubby screw driver would have been handy! Haha but anyways it didn't look dirty like I was expecting but I polished it with the sos pad. Fired it back up and it's working. Makes sense if it doesn't always detect flame due to debris, kicking it off for safety of course. And then eventually it would detect the flame which is why it worked part of the time. It all makes sense I will remember this for the future! Thanks a lot for your help, hopefully that's all!

 

It doesn't actually get "dirty". It gets covered in residue that's in the gas and forms an insulating coating. The flame rod doesn't sense heat.... it's actually conducting voltage thru the flame. So that clear, hard coating that forms turns into an insulator. Your scrubbing the rod removes that coating and exposed clean metal again.

That cleaning should be done once a year.

 

Oh man great to know. Thank you once again