MN 48XZ-36090311TP Carrier Duel Fuel with 1068-83-115A Furnace control Board. Home Owner called me saying his Heat was out. Went and checked out this unit and The Board was flashing a code of 5 yet it was running....Reset it and it ran fine for me. Then last night he says he got up in the middle of the night and its off again. Thinking of changing the board but I have heard of some other problems with these units. He said he fiddled with his Carrier Thermidistat and it started back up. I am sure it is flashing code 5 again and running. How can it be starting with the board in Ignition Lock Out? Anyone had this problem?
Intermittant Problem with Carrier Duel Fuel
craigcracker7
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MN 48XZ-36090311TP Carrier Duel Fuel with 1068-83-115A Furnace control Board. Home Owner called me saying his Heat was out. Went and checked out this unit and The Board was flashing a code of 5 yet it was running....Reset it and it ran fine for me. Then last night he says he got up in the middle of the night and its off again. Thinking of changing the board but I have heard of some other problems with these units. He said he fiddled with his Carrier Thermidistat and it started back up. I am sure it is flashing code 5 again and running. How can it be starting with the board in Ignition Lock Out? Anyone had this problem?
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Ignition Lock Out
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The Unit was trying to start while it was flashing the lock out code. I wittnesed this with my own eyes....I have never seen one do that....I could smell the gas but it would not ignite. Spoke with him just a few minutes ago and he says that he is removing the Thermidistat from its base, puts it back and the unit will start and run fine half way through the night. I have not wittnessed this so I am not sure. I have seen it running just fine with the code flashing also....apparently this is after he has removed the Thermidistat and put it back on.....Going back tomorrow to look at it again......I am still leaning towards the control board because I have never seen one run or even attempt to start in the Ignition Lock Out mode...
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Update: Went back and pulled out the burner assembly. Removed the Flame Sensor and Ignition assembly. cleaned them both up with steel wool. They were fairly dirty but I have seen worse. Also cleaned the burners and manifold. Basically Cleaned out the entire Assembly. Checked out the limit switches which were fine. Also checked the Heat Exchanger..also fine. Put the assembly back in and reattached the gas line. Reset the Thermidistat to auto and and started the unit..The Outdoor Temp sensor was at 34* so the gas should have come on. The Compressor came on instead and was running just fine so i engaged the defrost mode just to see if she would go ....it did and the gas fired right up. Set the unit up to run in the emergency heat mode....It ran fine through 4 cycles...determined that the Thermidistat is bad and I will be replacing it as soon as the home owner can afford it. I am still perplexed as to why the unit would start and run when flashing the Ignition Lock Out Mode....
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The thermidistat is set for backup gas heat to come on at 40* with the outside Ambient Temp being 34* , The Gas heat should have come on. The Heat Pump came on Instead....
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