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Secondary gas line


mridgeelk
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Hi,

That's feeding a trickle of fuel to the pilot light, which means, at least in my mind, that you've got a furnace there that's probably well beyond the end of it's normally-expected 20 year service life. Did you take that galvanized puff shield off to look at the welds around the burner tubes?

Weird place for that gas line to connect to the main line. Usually I think it connects to that upper orifice you see in the photo - the one with the rund cap that's slanted toward the camera. This one seems to have some other type of thermocouple device connected. When the shutoff valve on the line is turned off, will it cut off gas to the pilot as well as the control valve or will there be gas flowing even when the valve is off? If the latter, I'd call it for correction or at least a look-see by an HVAC guy.

It would help if you'd taken some closeups of the control valve and the thermocouple arrangement. That angle makes it hard to see what's been plumbed around that control valve.

When I get a furnace that old, I'm not shy about saying to the client - even when it's working fine - that it's so old that I wouldn't be surprised if it failed as I was driving home.

ONE TEAM - ONE FIGHT!!!

Mike

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That appears to be a 90% valve. If the thermocouple to the burner drops out, only the burner shuts off. If the pilot drops out, the burner could conceivably continue to fire. Modern valves are considered 100% combination valves meaning if the pilot drops out, the entire valve closes. See the winged handle on the pilot shut off right where it exits the gas cock? Unless you shut this little cock off, gas will continue to the pilot. There is a TC to to pilot valve visible in the lower foreground. What is not so visible is the main valve. Some of these setups have merely a medium pressure regulator coupled with a solenoid.

This dinosaur belongs in a museum. I would be shocked if the heat exchanger wasn't burned out. It may hit 50% efficiency on its best day. Should have been replaced............about 30 years ago.

One thing to document on these is whether the controls appear to be original or cobbled together. Often, you'll see gas conversions where parts have been replaced over the years with whatever works. You never do that with modern equipment. For instance, if you replace a thermocouple with a non-OEM type, you change the dropout rate and thus void the warranty and listing.

Interesting find!

HTH,

Hearthman

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Originally posted by mridgeelk

Originally posted by hausdok

Hi,

Did you take that galvanized puff shield off to look at the welds around the burner tubes?

A bit of an unusual question. Many inspectors have been trained to avoid anything having to do with the exchanger. It's some sort of instilled phobia that I think separates the newer inspectors from those who have been around for a while.

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Originally posted by Eric B

Originally posted by mridgeelk

Originally posted by hausdok

Hi,

Did you take that galvanized puff shield off to look at the welds around the burner tubes?

A bit of an unusual question. Many inspectors have been trained to avoid anything having to do with the exchanger. It's some sort of instilled phobia that I think separates the newer inspectors from those who have been around for a while.

I always pull those off. How else can you see obvious external clues possibly indicating a deteriorated heat exchanger such as rust flakes? Are they honestly telling inspectors in training not to perform simple tasks such as this?

IMHO, 'taint right.

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Are they honestly telling inspectors in training not to perform simple tasks such as this?

Well I can answer that question for ya. Yup, but not just telling, more or less berating you not to as it opens up a can of worms. Stories of how inspectors were accused of breaking it by opening it. At least the class I took, except for the electrical panel, we were "advised" not to remove anything on anything.

But I think it's a company line as when I spoke to one of the instructors off line I made a comment about it and he just smiled and sorta nodded and I caught the hint.

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This is just like the folklore about quoting code in your comments. I have seen Kurt ask an industry insurance leader straight up in a public forum to show any verifiable case in which such things have happened, the response is silence. I am sure if this instructor was backed into a corner he would say he knows someone who knew someone that.....

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Originally posted by sepefrio ... At least the class I took, except for the electrical panel, we were "advised" not to remove anything on anything. ...

When I was inspecting in the Houston market I experienced a local community college CE class on electrical. Was taught by TREC licensed HI who also was a licensed electrical person.

He made a very strong point to "never" remove the deadfront cover for a HI. Questions flew left/right, but he held his ground, but he never gave a good reason why.

He kept saying to refer all electrical to a licensed electrician.

We figured he was on that side of the fence more so than an HI and he could make more $$ there.

Just additional anecdotal information. [;)]

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That sort of advice (don't touch nuthin', call an expert) comes from those that like the idea of HI as barely functional moron. If one traces the source, it usually ends up at a trade guild, an education mill dependent on a never ending source of compliant goofballs, or someone not interested in HI work being considered a profession.

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One point to make is that with this type of furnace the heat exchanger is not to difficult to check. The burners can be removed easily and they make long, skinny, mirrors that can be inserted in the burner chamber. Shine a flashlight on the mirror and you can get a pretty good view of the inside of the heat exchanger. The whole process doesn't take more than 10 minutes or so.

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That's true, but I've owned this sort of furnace, and I used to watch this one area of weld open up when the heat exchanger got hot, and then close back up again as the exchanger cooled off. In the sorts of conditions you describe (burners out, exchanger cool), you aren't necessarily going to see anything bad.

I have never opened up a really old furnace, and not found a compromised weld, seam, or small crack.

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Most of the newer inspectors will not appreciate my comments, but here goes.

I have checked exchangers with: peppermint oil, sodium chloride, butane torches, copper plates, draguer tubes, "canned air", hundreds of mirrors, snake lights, 50 kinds of flashlights, misc meters and sniffers, siphon tubes, squirt bottles, yada yada yada. Point is I wanted to know everything I could about that device. I needed to know. My client expected me to know. Can't teach an attitude in a two/three week course. It just makes the job more difficult and prevents you from making $175,000.00 your first year.

BTW, I also have been told any hole less than 1" or smaller than a half dollar is no big deal and cracks 4-6" long are normal.

We can all learn bunches of info on this site, but you can not learn to be an inspector. I don't want to hurt anyone's feelings, but the original question was pretty basic and really surprised me.

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Well, after lurking on this thread for a few days, I will freely admit: I would've just told the customers to get a new furnace.

Wouldn't have gone looking for cracks, wouldn't have moved anything out of my way, wouldn't have monkeyed with it at all, other than removing the front cover and taking a (maybe) 30-second look inside.

It's old. It's rusty. It's inefficient and obsolete. Just junk it. The sooner, the better.

WJ

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You're perfectly right, Walter. But a majority of buyers won't have enough cash on hand to afford a new furnace. And the sellers, if they disclosed that the furnace was a million years old, won't pay for a replacement unless the heat exchanger has failed or there's some other egregious problem. That's why I would have removed the burner shield, stuck my nose in the heat exchanger, and tried to find a reason for the sellers to buy my customer a new furnace.

I'm not arguing. Just saying.

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Originally posted by Bain

You're perfectly right, Walter. But a majority of buyers won't have enough cash on hand to afford a new furnace. And the sellers, if they disclosed that the furnace was a million years old, won't pay for a replacement unless the heat exchanger has failed or there's some other egregious problem. That's why I would have removed the burner shield, stuck my nose in the heat exchanger, and tried to find a reason for the sellers to buy my customer a new furnace.

I'm not arguing. Just saying.

Nothing wrong with just saying. Could be a little difference between Nashville and Lexington. Best I can recall, every time I told a customer to get a new furnace, they got a new furnace. I was fortunate enough to have few, if any, doubters. (And y'know, sometimes the RE agents adjust their fees to close a deal.)

That said, my original editor at the Scene hired me to look at his octopus furnace years ago. I told him that it was 80 years old, nothing but a big can fulla fire, with no real safety equipment.

He told me he'd junk it when the fire went out.

WJ

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I don't think those old Octopi furnaces could fail; damn walls are 2" cast iron.

I'm w/Les. I've tried every way from Tuesday to figure out how to examine a heat exchanger, and I don't think there is any good way that doesn't involve taking the whole darn thing apart.

Heck, my own ancient furnace that I checked w/my Firerite Pro, dismantled, looked @ w/snake mirrors, etc., etc...., had a crack that I couldn't see until I tore the thing out & looked inside for real. All that "pull the burners, remove the flame shield" investigative stuff might get you lucky, but if I had to bet my teeth, I'd be betting >98% of all cracks are never going to be seen w/out complete dismantlement.

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Originally posted by kurt

Heck, my own ancient furnace that I checked w/my Firerite Pro, dismantled, looked @ w/snake mirrors, etc., etc...., had a crack that I couldn't see until I tore the thing out & looked inside for real. All that "pull the burners, remove the flame shield" investigative stuff might get you lucky, but if I had to bet my teeth, I'd be betting >98% of all cracks are never going to be seen w/out complete dismantlement.

Exactly. Add up the cost of dismantlement, remantlement and disposament, and it's way better just to buy a new furnace.

At the other end of the stick, I've got a 23-year-old Carrier air conditioner taking care of my downstairs. My HVAC guy is a little skittish about touching the condenser. "It might go 30 years," he says, "if we don't mess with it."

WJ

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While it's true that the furnace shown in the picture deserves retirement I think it's still a good idea to discuss different ways of checking them for the benefit of those that have not been exposed to this type of thing.

I've picked up a lot of great inspection techniques, on areas of the home that are not my strong suit, from the knowledgeable folks here through this type of discussion.

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Terry,

I agree with your statement. But, I also think it is very important for inspectors to develope a healthy curiosity or a fire in their belly to learn and know.

Most of the authoritive voices on this board know how to read and write and observe. I happen to be an expert reader and observer and a lesser writer. I know attending an inspection with me is a whole lot more fun than reading my report. Shoot, even having a hamburg at the bar and talking inspections is more fun than my report. I am sure WJ writes a report that is more fun than mine, but likely is my equal at the inspection site. And I know Kurt is entertaining (aka loyal oposition).

This is a fun business, but has had the bar lowered for the past decade.

Mike, and several others, has always been a national voice for a formal academic education. One day it will happen.

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