Flame Roll Out

skystew

I have a 20yr old Trane furnace; during a pm inspection the tech called me to point out what he called a 'flame roll out' upon start up. He said that the flame was acting in a downdraft mode instead of an updraft. He felt that there was possibly a crack in the heat exchanger but wasn't 100% sure. His recommendation was to shut the system down for safety reasons as the gas supply pipe ran right by the opening where the burners were & where the flameout occurred. He further suggested that the furnace be replaced given what he saw & the age. My question; is this something repairable or is he pretty much right on target - replace the furnace? He calculated there was only about a 57% efficiency as well. I just wanted to know if there was a safe & reliable fix for the furnace.

thanks

Houston204

If the blower was not running when roll out occurred, it could be a venting problem.

You can always get a second opinion.

That said, I would not have a 60% furnace on my house. I would (and have) upgrade to a modern furnace. They are much safer.

skystew

when the roll out occurred the blower had not come on yet....nice to hear another opinion; venting issue was not mentioned as a possibility of the roll out. Unfortunately, these are economic times..if it's a simple fix with the vents then I may have to do that for the next 6mos-1yr...a 2nd opinion might be in order and might as well go with someone reputable who can also give me a quote on a new furnace...any thoughts on 2nd stage vs variable speed furnace?

thanks

Houston204

Look in your vent pipe for a bird nest, bee nest, or dead animal. Verify that the vent cap isn't damaged or blocked.

I think that most 2 stage furnaces have an ECM motor.
(Unless you refer to a variable position gas valve, but they would still have an ECM motor)

The ECM 2.3 and 2.5 were prone to failure after 5 or 6 years and very expensive if not under warranty. The ECM 3.0 seems to be better.

The ECM X13 uses speed taps and doesn't seem to fail like the 2.3 and 2.5 .

skystew

Last year I had my vent cap replaced due to rust. I used a reliable roofing company...I will still have a look to see if anything is blocking it. Nevertheless, the furnace is 20yrs old...actually, I have two furnaces but the one upstairs (just off the hallway, not attic) has the flameout...the tech said the furnace downstairs was showing signs of a flameout too, but had not come pass outside the heat shield/plate as of yet. You are a little over my head with the reference of the ECM moter...the tech suggested getting a variable speed furnace when I was ready. Sounds like the 2 stage has 3 speeds...low, medium & high.

beenthere

What he is calling roll out. May be caused by vent problems as Houston said. This can be caused by the flue/chimney being too short. Too much gas pressure at the manifold. Dirty burners. Dirty heat exchanger, etc.

The ver 3.0 ECM is only being used on Carrier/Bryant units, as far as i know. Maybe ICP units have it now also. Since they are owned by the same company.

The first generation ver 2.3 and 2.5 didn't have speed limiting built into them. All new ones of those versions do. So they are not prone to early failure.
And the ones that seemed like they were. Were usually installed on grossly undersized duct work.

2 stage furnaces come in both ECM, and standard PSC blower versions.

If you have A/C, and live in an area that has high humidity in the summer. A VS ECM can help to lower your indoor humidity in teh summer.

Get a second opinion. But, at 20 years old. That unit is pretty much at its end of usefull service.
Its heat exchanger can probably be replaced. But, you would still have many other parts that could fail at any time.

skystew

Thanks...the bottomline is that the furnace is 20yrs old...a new one is overdue. Yes, I live in the Atlanta area so there is a high humidity factor...I'm strongly leaning towards getting a Trane..it's what I've had for a long time now & fairly reliable...if they don't have an ECM, as you say, only found in Carrier/Bryant then I'm sure they have something comparable; I also think it would be wise to go with at least 90% efficiency...everybody keeps pushing variable speed..will look at it all & have the necessary home tests done first before I settle.

beenthere

Trane has, and have for many years. A furnace line with VS ECM blowers.

Carrier used the version 2.3 and 2.5 for many years( the 3.0 is a new release).
Don't be scared off of them.

Yoyizit

Half of resi. HVAC stuff lives longer than this, and half are replaced at 20 yrs or less, probably for reasons other than normal wearout.

http://www.acca.org/Files/?id=186