Hi,

I have a carrier furnace that won't stay lit, model 58sta135. In my opinion It goes through the complete sequence but flame goes out and after 4x's and it locks out. I've replaced the flame sensor twice. The 1st time replacing got the unit working for a couple of days then it stopped working, so I purchased another thinking the part had gone bad, but this didn't work as the unit won't start lit. Does this sound familiar to anyone? Please help

Omar in IL

I'll upload a video of what's happening when I get a chance

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It flashes code 33 "ignition failure" when unit doesn't stay on.

You have a few things you can check. Make sure you have a good flame sensor wire( wire ends do go bad and break away from wire) any wire with spade ends will work to test. Make sure your flame sensor or wire is not grounded out and touching metal. I notice the gas valve ground wire to the left of the burners if this wire is not grounded correctly with the gas valve the system will go out on flame failure. Flame sensors don't go bad they just get dirty. The only time they go bad is if the ceramic around them is cracked or broke.

Thanks for the response Ttop. I will check the sensor wire and the ground when I get home tonight. Keeping my fingers crossed and hope I find the smoking gun

I checked out both wires(ground n flame sensor wire) and both ohmed out @ .3ohms. I checked to make sure flame wire is not touching any ground. Im starting to lose it here, still no workie

I've checked the flame sensor for microamps and got 1.2 reading, not sure if its strong enough to tell the bouard there's a flame present. I'm starting to think the board is no good, but I hope not.

Omar

Anybody have any troubleshooting tips or advice?

Well I finally got the damn thing fixed. Yay! It ended up being the board which sucks, though I did get to know my furnace pretty well. If anyone has ?'s about this carrier model, I can help you

I have same problem you had but I also replaced board and still not working. Any ideasa?

Double check that the board is wired correctly. Its easy to wire up wrong. Check w wire diagram