Look inside your furnace

[pgr32e]

Just thought I'd post what I found when I pulled my furnace after CO readings from our little jaunt across the country last fall hit 46ppm. We bought and used an electric heater after the first night. The knife slides quite easily into the split in the plenum joint and the corrosion lower centre is self explanitory. The replacement furnace is sitting on the bench next to the pictured one.....Phil.

[Stefrobrts]

Yikes, glad you had a CO detector in there!

[pgr32e]

Actually, the CO detector was bought at the same time as the electric heater. It was after using the furnace the first night out on a month long trip and finding the smell not quite right and a funny little plip noise after it shut off. looked in the view port on the furnace and saw the burner wasnt shutting off all the way, the plip noise was the pilot lighting a small leak that was caused by the valve not shutting off all the way. So, we were lucky, and the rest of the trip(sept7 to oct7) was with the ceramic heater. We were comfy down to about -7C some nights with just one 1500 watt heater and a couple of good blankets. Didn't find the holes till after we got home and I pulled it out.

[Bluto]

How old is the furnace that had the problem?

[withidl]

If you don't cover the furnace external opening during the summer Mud Dauber wasps will also infest the furnace internals.

[Aage]

Originally Posted by Bluto

How old is the furnace that had the problem?

I'm gonna bet that it's 37 years old, just like mine...

[tinman54]

Co detectors are a good thing and should be replaced at least every 5 yrs. Starting to be mandatory in a lot of homes now. Furnaces should be checked and inspected like that at least every 2 years, especially vintage units. Good the problem was detected right away!

[Aage]

Well, originally I had thought of pulling out our furnace and doing an overhaul, but then someone pointed out that a house model furnace would never be left in service for anything approaching 30+ years.

Then I considered the fact that this unit literally lives nearly outside all year long and is continuously exposed to moisture. Just look at how they all corrode inside.

I'm buying a new one this year! I am now fully convinced that it is foolish to play around with something that has the capacity to completely destroy our TT and cause extreme danger to humans.

[pgr32e]

Yes, the furnace was 37. On a coincidental and painful (in the pocket) note, just replaced the furnace in my house which is about the same age.....there's a learning note there somewhere.....Phil.

[Jammer]

Glad you caught it before there were any serious repercussions.

With most furnaces it's end of the road when the heat exchanger fails like that because by the time it's happened the furnace is usually old enough that replacement parts are no longer available. I suppose that with some really simple heaters like the panel ray the heat exchanger has such a simple shape that it might be possible to make a replacement or adapt one from a newer heater but in most cases that isn't practical.

A CO detector won't catch these problems at an early stage if the burner is working properly because the CO levels won't be high enough, making it important to use a visual inspection as well.

There's a collection of articles here on heat exchanger inspection in stick houses:

Guide to Furnace Heat Exchanger Inspection, Testing, Leaks - Hot Air Heat Troubleshooting & Repair Guide