Rheem flame sensor


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Old 03-11-11, 07:18 AM
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Rheem flame sensor

I have a Rheem gas furnace, that is having ignition problems. It will light for about 3 seconds, then stop. I'm thinking it's the flame sensor that needs cleaning. But, I'm not sure where the flame sensor is located, and how it's cleaned. there is a round little deal at the top of the flame box, with what looks like a window facing toward the burners. Would this be it? If so, how do you clean it?

thanks!
 
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Old 03-11-11, 09:45 AM
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Your furnace probably has a hot surface ignitor that glows white hot to light the gas. The flame sensor is typically on the opposite side of the furnace from the HSI.

It's usually a rod about 1/8" in diameter that sticks up into the main burner flame, and has a single wire coming from the bottom and going over the the circuit board.

Usually you just need a screwdriver to remove the flame sensor. Use a wire brush to brush off the invisible oxides that can coat the flame sensor and prevent the flames from touching the metal of the flame sensor.

Cleaning the flame sensor annually as part of regular maintenance is suggested to avoid outages.
 
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Old 03-11-11, 02:24 PM
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Thanks, I'll give it a look tonight, and see what I can find!
 
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Old 12-15-12, 01:29 PM
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I had the same symptom but a different cause. This Rheem is installed in our garage, and apparently the rain leaks in through the flue.

This problem only happens when it rains, so I was investigating why moisture would be causing the problem.

Came to this thread and looked at the flame sensor (thanks to this forum). Removed the sensor, cleaned it with some sandpaper and reinstalled. Still no dice.

As I'm staring at the furnace I'm trying to figure out why moisture would cause the problem when I see a drop of water from a bend in the flue. Follow down from where the bend is, and, voila, there are the two electrical connectors that go downstairs to the computer.

I touch them and realize they are soaked in water. Water was puddled in the tops of the connectors.

So I disconnected the two connectors, dryed them out as much as possible with a paper towel, sprayed liberally with electrical contact cleaner, added some dielectric grease and reconnected.

Problem solved. So it may be your sensors, or the connectors may be corroded. Check both.
 
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Old 02-16-15, 02:03 AM
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...I have a Rheem gas furnace, that is having ignition problems. It will repeatedly light for about 3 seconds, then stop until it errors out. I'm thinking it's the flame sensor that needs cleaning.

Read more: http://www.doityourself.com/forum/ga...#ixzz3Rt86YhAF

I had the same exact problem "Burner lights for 2 - 5 seconds and then shuts off" on a 7yr old Rheem Powervent. After initially reading similar threads here on DIY I tried the primary diagnosed solution of cleaning the "flame sensor". This immediately worked, where I had tried numerous other tips and suggestions with no success.
My HWT ran without an issue for about 1.5 weeks and then we ran out of propane (with the extra cold temps and all the recent storms we've had up here in the NE). This took several hours to have the vendor come over and refill, but then after the refill the HWT failed again. I attempted to clean it again, although it looked pretty clean to me (compared to the 1st time), this did not resolve the issue this time. It seemed to me as though wasn't getting enough Gas pressure from the Gas Line or Intellivent, so I opened these up and spend numerous number of hours over a few days trying to resolve. My HWT is on it's last legs due to corrosion, so I didn't want to spend the money on have a tech come in only to be advised to replace it or whatever it would cost knowing that probably in a few months I'd probably need to replace anyway.

I tried many many different recommendations, I read the usergroups and studied the OEM manuals enough to get certification on HWTs, but still couldn't get it to run for more than a few seconds.

Finally, after trying almost everything else (related to gas line and burner ignition process), I decided to try and re-clean the "flame sensor" because everyone with similar issues kept raving about how their's was resolved by this simple cleaning, and one person had indicated how when their's was clean, it had a nice shine to it... well, mine looked pretty clean, but it was definitely dull. So I took it out and more as a step to eliminate the option than any expectation that it would work, I cleaned it with scotch brite and noticed that a lot of residue came-off the sensor?? ...and I was able to get a pretty decent metallic shine to it after some scrubbing. I then put it back and attempt to run it again and ...it didn't run for more than a few seconds the 1st time, BUT ON THE 2nd TRY, IT STARTED UP AND KEPT ON RUNNING!!!

I couldn't believe how much time and effort I had wasted on troubleshooting just because I made an assumption of how a clean "flame sensor" would look like. So I promised myself that I would join this forum in order to post my twist/experience just in case anyone else is in and or ever encounters a similar predicament!!!

Thanks to all members and technicians who've shared their experience and knowledge on the subject.

TeeW.
 
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Old 02-16-15, 12:22 PM
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Thank you Tee & welcome. Your experience should be a good lesson to folks. We so often hear "I took out the sensor or I looked at the sensor & it was clean". It only takes a film to disrupt the micro amp current.
 
 

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