Trane broken switch


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Old 02-23-14, 08:42 PM
J
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Trane broken switch

I was hoping to save a few dollars and troubleshooting an issue with my Trane furnace. In trying to test and clean a switch it broke when trying to remove the wire. Can someone tell me exactly what that switch is and identify it so I can replace it.

Furnace issue - Imgur
 
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Old 02-23-14, 11:09 PM
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Welcome to the forums.

That switch is called a flame roll out safety switch. It detects flame outside of the burner chamber and shuts the burner down if it detects high heat.

I'm curious at all the rust near the draft hood on your furnace. It looks like there may be a venting issue there.
 
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Old 02-24-14, 09:51 AM
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Thanks for taking the time to respond i do appreciate it. There is a humidifier unit that is installed above the furnace. When ever I have someone in to service the furnace they all shake their head and say that was a bad design and I certainly agree with them. My suspicion the humidifier may have leaked in the past (I have turned the water off and no longer use it) with the combination of the water, age of the furnace over time the rust has spread. From what I can tell the house was built in 1988 and this is the original furnace. I had two HVAC companies come take a look at the furnace.
Company A the repair person took a quick look at the heat exchanger and said this doesn't look good. he went to his truck and had a snake camera and examined it closely.. He had me look at the camera as well a small b/w 2 inch screen. To be honest I could see what might have been cracks or maybe just the seams. I of course have no idea what a "normal" view would be. He said they could replace the heat exchanger for 2500 but recommended a new Furnace and AC unit. He shutdown the unit and had his salesman contact me that night. I met with him and of course a new furnace is over 10K.
He was pushing for me to get the financing setup so they could install the furnace the next day.
A big purchase like that I wanted another opinion or bid.

Company B came out he examined the heat exchanger and said it could be cracked but said he wasn't setup to look up inside it. He said he could replace the switch and that I had a bad thermo coupler as well for 400 but he also recommended replacing the furnace and AC and set me up with his salesman who I haven't met with yet.. he left the furnace shutdown also.


I can bypass the bad switch and the furnace runs but of course I know that's unsafe and would never put myself or family in any danger. I have been running it periodically in the morning to warm the house and then before going to bed. I stay in the furnace room while it runs and then turn the power off. I was hoping to replace the switch myself but not sure about the thermo coupler since I have no hvac experience. The possible crack in the heat exchanger raises concerns as well. I have a carbon monoxide detector installed, new 2 months ago so would hope if the furnace is cracked and leaks the detector would warn us.. I did read online that companies do like to come out and tell you the furnace is bad and scare you into getting a new furnace. Again I do realize the furnace is 26 years old and I need to replace it in the future I prefer not to be held hostage and have to purchase one in the next few days. If I can replace the switch and then purchase a furnace in the next few months that would be preferable. Again I would not want to put us at risk... I am considering having a third company look at the furnace but so far have paid for two service calls.

Sorry for the length of the note but wanted to be sure all the details were covered.
 
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Old 02-24-14, 11:03 AM
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The coloration of the door shows that gasses are dumping out. To prove it to yourself, take a cigarette lighter and hold it just outside of the draft hood opening. If it draws the flame in while not running, you have positive draft. I'm betting it blows the lighter out when it's running. If so, get a second opinion.
 
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Old 02-24-14, 06:50 PM
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He said he could replace the switch and that I had a bad thermo coupler as well
Obviously the switch is broken but how did he arrive at that it needs a thermocouple ?
I'm pretty sure that furnace uses a hot surface igniter.
 
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Old 02-25-14, 12:41 PM
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Yes that's something I should have questioned (the bad thermo coupler). After giving this some thought and thanks to a couple recommendations I contacted a third company. A small local company. I had two people tell me the owner was a very honest and fair person. I called him and he himself came out late yesterday. He did confirm and showed me the cracks in the heat exchanger. He tested for leaks but did not detect any but his recommendation is to replace the furnace as well. His quote is quite a bit lower (tempstar) vs (Rheem from the other company) and he does seem to be very honest and takes pride in his work.. I just need to weigh the pros and cons of each proposal and decide. I appreciate everyones feedback and am glad to have found this forum. Look forward to utilizing it in the future on other DIY projects. Hopefully not in the HVAC area though.
 
 

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