Posted: 1/3/2011 8:47:22 AM EDT
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Furnace problems are getting worse. What's the step-by-step trouble shooting routine for a furnace?
For the last year or so, very intermittantly, but increasing in frequency, the blower will turn on, but the fire doesn't. I turn it off at the thermostat for a minute or so, then turn it back on and the flame comes on. This morning that didn't work the first three times I tried it (lower twenties this morning, BRR! Thang God for my fireplace insert.) Forth time was a charm I guess as it turned on before calling a heating and cooling guy. I just came home from picking up my girl from school, and the blower was running, but no heat. Shut down, start, and it blew warm briefly, and just shut down. It turned on again, and is blowing cold. Igniter maybe? How do I troubleshoot this thing? Inter-City Products, LaVergne, TN. (Arcoaire) Model GUI100A016AIN Serial # L940280736 MFG# GUI100AGAIN Original w/ the house, 1994 construction. Thanks! K Edit: Arcoair RPJ II. I just changed the filter as I remembered that I didn't do that after doing drywall in the basement.  Reading online (actually about a comfortmaker RPJ II), people are suggesting cleaning the flame sensor / thermocouple. I guess I'll try to see if that works.
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OK, a bit of internetting told me to clean the thermocouple and flame sensor. Since I'm not 100% sure what a flame sensor is, I looked, and there was a tube that looked just like a thermo couple, so I pulled it and cleaned it off w/ some 000 steel wool. On the other side of the burner was what I would describe as a glow plug. It got bright red, and the burners kicked in, so I assume that's the igniter. It had a powdered metal surface, so I just lightly hit that w/ the wool.
Also, I changed the severly clogged w/ drywall dust, filter earlier. It seems to be working now. K |
| Cleaning the flame sensor and the igniter is a good start but believe it or not, MAYBE the best thing to clean was the filter because there may, often is, should be, could be, a tube that senses pressure in the air flow portion of the furnace and if that air flow is too low, it may not ignite because it will not move the diaphragm in the pressure switch that trips a microswitch that tells the main board that all is well. |
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Quoted:
Cleaning the flame sensor and the igniter is a good start but believe it or not, MAYBE the best thing to clean was the filter because there may, often is, should be, could be, a tube that senses pressure in the air flow portion of the furnace and if that air flow is too low, it may not ignite because it will not move the diaphragm in the pressure switch that trips a microswitch that tells the main board that all is well. The OP stated that the ignitor looked like a powdered metal surface. This describes a silicon carbide ignitor. These are fragile and should never be cleaned. 
Also, most residential furnaces don't have this type of pressure differential air switch. If there is an airflow problem due to dirty filter, most likely the furnace high limit switch will trip the furnace. |
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Things seem to be running fine. I haven't had any non-starts since cleaning up the flame sensor (and barely touching the ignitor! I recognized not to polish that!)
I agree that the filter was probably my main issue. Kind of forgot about all of that drywall dust!
K |
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Does your circuit board flash fault codes when there is a problem?
Look on the blower compartment door. Is there a peephole to look in at the circuit board, This is to see a fault code flashing. Do not reset power to the unit as this will erase the code. This will help diagnose the problem. |
