Help identifying flame sensor


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Old 11-20-15, 04:35 AM
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Help identifying flame sensor

I'm having problems with my gas furnace staying on. The updraft blowers turns on, the ignitor glows bright orange, gas turns on, and the flames ignite. After a few seconds, the gas shuts off and it starts it's cycle over and tries this a few times before it locks it up. I've narrowed it down to a bad flame sensor. I've already taken it off and cleaned it with steel wool. The furnace is a Ruud Silhouette 2 but the unit caught on fire a few years back and a local company came out and replaced most of the inside. From everything I've read and seen online the flame sensor I took out does not match what is supposed to be in it. This is what I took out: Imgur: The most awesome images on the Internet If this is the flame sensor, this one has 2 wires instead of 1. Also the wires have been spliced with wire nuts into 2 separate wires. Can someone identify this one so I can order a replacement?
 
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Old 11-20-15, 06:00 AM
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I am not familiar with your specific furnace but that looks like the hot surface ignitor. Does it glow white hot when the furnace lights? Look at the side opposite the ignitor for a single rod that enters the flame when the burner is lit, that would be the flame sensor. In my opinion steel wool is not the proper material to use in cleaning a flame rod/sensor but a common (green) Scotchbrite works better. Also clean any wire terminals and ground wires between the circuit board and the burner housing.

Note: A few furnaces use the ignitor as the flame sensor as well. I do not know how these work but the same remarks about cleaning the ground wire connections apply.
 
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Old 11-20-15, 06:04 AM
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Since the furnace has been operating for a few years, forget about the 1 or 2 wire issue. The flame sensor has been doing it's job. There is no way to know if the local company used original Ruud parts after the fire.
The first thing I would check is the flame sensor position. The eye must have an unobstructed view of the flame. It also should be clean. Being it worked for 2 years, make sure nothing has gotten between the flame and the sensor. If cleaning the eye of the flame sensor does't correct the problem go to a local HVAC store with the old sensor and they should be able to match it. The sensor is not polarity sensitive so connect the 2 wires either way.Good luck.
By the way, I like your pink fingernails.
 
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Old 11-20-15, 06:09 AM
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The eye must have an unobstructed view of the flame.
I know of NO residential GAS BURNING furnace that uses an optical flame sensor so your entire post is irrelevant.
 
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Old 11-20-15, 07:40 AM
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After doing more research I went back under the house and found the actual flame sensor. I replaced it with a new one and I'm still having the same problem. I also checked the board and it has 3 leds on it Ok, Power, and Flame. Ok and Power are lit up but Flame never lights up. The board was also replaced when it caught on fire or at least the invoice says I payed for one.
 
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Old 11-20-15, 08:31 AM
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You are showing a picture of a hot surface igniter
 
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Old 11-20-15, 08:48 AM
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The flame sensor MUST be engulfed in the flame. When the burner lights.... the flame light should come on. In your case it's probably flickering dimly. The LED is an indicator of flame sense strength. It only lights up when burner is lit.
 
 

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