They found a crack in the “heat exchanger” and gas could leak. I don’t have a CO detector.
With steam, when you change the boiler, you can have issues connecting the new unit to the size of the existing steam pipes for the right pressure. Don’t blame me on that one, the plumber forums mention it.
But I’m glad to hear so many here have old systems. Ours is now pushing 40 years.
BB, our inspections are part of the maintenance contract, which we have used for small things like the ignitor going out in winter. And we also get the chimney inspected. Old enough house, better safe than sorry.
You may want to get one or more CO detectors. Choose the kind with the numeric display so that you can see non-zero levels of CO that are below the warning threshold, so that when you see any non-zero level, you know to get the fuel-burning appliances checked and repaired before they produce enough CO to become a hazard.
Yes, cracks in the heat exchanger can result in exhaust with CO being blown into the house.
Oh, that (if the crack is indeed there) is a bummer - it is a safety and a code issue possibly.
Mr. B observed carefully what the inspector did when we called for inspection after living in this house for a year… Mr. B said it was a load of BS which Mr could have easily done himself. Maintenance contracts and home warranties in our are not a common thing in our area, as far as I know.
New gas furnaces have efficiencies in the high 90’s. Time to get a new one.
Skeptical mind! Yes, the crack is indeed there. They showed me. We have a twined system where two identical heaters are connected to act as one. It’s easy to compare when one has a crack and the other not. The crack is going to get bigger if unattended. Are new gas furnaces as well made?
- Gas furnaces are one of the cheapest, simplest home heating systems there are.
- That does not mean most *energy efficient* or cheapest to operate
- There are basically standard and high efficiency models and the market shifted in favor of the high efficiency models about 22-23 yrs ago.
- Unit costs range from about $500 for standard to about $1,000 for high efficiency models. That does not include profit and installation.
- Because they are so cheap, a major repair like a heat exchanger indicates a new unit, primarily due to labor cost and increase in efficiency.
- New gas furnaces are as well made as the older ones.
The heat exchanger is what keeps the combustion gases going up the flue, and yet still heats the air (or the water…depending on whether you have forced warm air or hot water baseboard heat) that the system uses. If there is a crack that allows mixing of the two airstreams, you’ll get combustion gases mixing with the air used to heat your house. Not good.
Check out this thread and the comments. There may be some funding available to you from Carrier. The thread is three years old, but it seems worthwhile to follow the one posters action of calling the company to inquire.
http://ths.gardenweb.com/discussions/2389791/carrier-heat-exchanger-class-action-settlement
If the heat exchanger is cracked, it may be condemned as unsafe and then it would be cheaper to replace. We wen through this. The issues are:
- High efficiency or not. You can get the same kind you have now, a traditional furnace that exhausts combustion gas up a chimney. These tend to be 80%+ efficient. Or you can get a high efficiency type, the kind that exhausts sideways. These are generally 93-98% efficient.
- Basic or complicated. Furnaces used to be "single stage", meaning they turn on and off. There are many varieties now beyond that, from ones that turn on a bit with the fan on so much and then higher to a kind that constantly adjusts how much heat it produces and how hard the fan.
Companies are pushing the most advanced type. Problem to me is they all involve circuitry that didn’t exist when a simple thermocouple would flip a switch to ignite the furnace. (That is, a coil of wire that expands and contracts as it heats and cools.) I have no idea how much/how often/how long these circuit boards and all the electronics will last.
Another issue is the state of ductwork. We didn’t redo ductwork so putting in a multi-stage furnace in a 140+ year old house didn’t make much sense. If your ductwork is efficiently arranged, it may.
Thank you for all the info. Very informative as usual. Ours is the kind that exhausts up the chimney. The duct work is 60 years old, pretty elaborate, not sure how efficient it is. Our present furnace is pretty efficient looking at my heating bill, not high and we have all single pane windows and three huge floor to ceiling picture windows.
dadx, the garden web site was wonderful. mine is too old to be covered under their settlement but it was good to know. I may still give them a call.
JustOneDad, great price estimate. I see the labor and profit is the large part of the cost. I remember getting a new furnace in the 80s and cost me about $3,000!
Yes, most installers will charge you whatever you are willing to pay, up to many times the actual cost and fair labor rate.
Exhausting up chimney indicates a standard model as high-efficiency furnaces require PVC exhaust. A new furnace should also include a provision for outside combustion air which will reduce the “leakiness” of your home. You may notice an increase in relative humidity during the heating season. In most cases, that is an improvement.
What you may mean is that you aren’t too bothered by your heating bill, but there is nothing efficient about standard burners, 60 year old ducts, and large single pane windows.
Please get (at least) one!!! Our CO detector sat in silence for years until our furnace developed a crack in the heat exchanger. There was also a vent pipe next to the furnace that was installed incorrectly and sent the CO into our house. This was not a problem when the furnace was operating efficiently, but when it started putting out large amounts of CO it was vented into the house. Fortunately our alarm went off (scared the crap out of us!) and we eventually replaced the furnace.
@mathmom, we wouldn’t have to change to hot air: we could opt for a new gas burner+boiler. But we would have to line the chimney because of the acidic nature of gas exhaust, which eats away at the mortar. That alone would cost several thousand, and at first they thought that it would be impossible because of the resulting size of the flue. By using the smallest possible furnace for our radiators, they could get it down to being just big enough. But the whole thing would cost $17K or so. And our current system is not horribly inefficient. The most efficient new models are not steam, so we would not qualify for a rebate.
I would like to switch to high efficiency forced hot air and get rid of all the radiators. The problem with that is getting heat upstairs. Some would simply rise, since we have two staircases. But some auxilliary heating might be required. It’s complex. And very expensive. Our radiators cannot be switched over to hot water.
CO detectors ASAP! Wisconsin started requiring them several years ago. We got one with numbers and the rest just with indicators- put the numbered one in the basement where the CO most likely to be found. Have since moved OOS so who knows what the new owners did to our placement.
It is worthwhile replacing the old technology with a high efficiency, two stage fan. Ducting outside is not that big a deal-they can run the pipes along the basement ceiling and through the wall. You may decide to improve any ductwork issues while you are at it to improve air distribution in your house. If you are replacing a furnace labor is a major part of the cost- you may as well optimize things. Do not be “penny wise and pound foolish”.
That’s too bad. I don’t think I’d fork over $17K either. I’ve been very tempted to get rid of the radiators and put in a mini-duct system which would also give us AC in the summer. But we don’t actually use the AC that much so I think I will put in a couple of mini-split units instead when we are feeling flush again.
I just got an estimate to replace the system, about 16K! To replace the heat exchanger alone would be about $2,700. What are major parts in a furnace? The blow motor is new. What else could go wrong? Just replacing the heat exchanger is less much and less hassle. I like that everyelse will remain as is. My house was an archetect’s own house and everything is a bit elaborate and something tends to go wrong when people fiddle around too much.
“Unit costs range from about $500 for standard to about $1,000 for high efficiency models. That does not include profit and installation.”
I don’t know what kind of unit you are talking about, I suspect you are talking about a hot water heater, not a gas furnace. Even basic units of low capacity (like 50,000 btu’s, like the small one we have for an expansion) are going to be in the 4-5k range installed, and the high efficiency ones are more.
Okay, I’ll go against the trend and tell you I would replace it. The heat exchanger is how the hot air gets heater, picture two cast iron pipes welded together, one of the is heated by the furnace firing, it gets hot, and the air from the house is circulated through the second pipe which picks up heat from being attached to the second pipe (this is a simplified view, heat exchanges are a little more complicated than that). If that cracks, if the pipe that has the heated exhaust from the furnace in it, CO can escape (and usually it is the heated exhaust pipe that goes. It basically doesn’t pay the replace the heat exchanger, with labor it will cost almost as much, if not more, than a new furnace.
The other reason to replace it is the efficiency, most modern furnaces are more efficient than they were were 20 years ago, and you can get high efficiency units that weren’t available back then (the ones that were were mechanical, which stank, I had one). Unlike others, I don’t think modern furnaces are not going to last, though yes they use control circuitry to operate, they still are a relatively simply beast (not talking the adaptive ones, talking the ones that simply fire when the thermostat calls for it). One of my units is 20 years old, doesn’t have any circuitry, and it is a piece of crap (the smaller unit in my attic for an expansion), on top of not really being put in right, it was a ‘contractor special’ that was a cheap unit. I also have a trane high efficiency as my main unit, and I have had zero problem with it and I would bet it would last as well as any unit from the past. The standard rule on furnaces back in the dark ages was they would last 25-30 years, and that hasn’t changed much. With routine maintainence, a decent unit will probably work as long if not longer than units did back then, because they burn more cleanly, I would bet they will last longer.
$16K! Holy Marbury. And I thought our $7K quote for a top of the line replacement furnace and some ducts/modifications of garage space was too much. Get a few more estimates and a couple of second opinions.
@bunsen:
Keep in mind that the work they wanted required ripping out the old boiler and the radiators and steam lines, it would mean putting in duct work through the walls (which isn’t easy), and would require putting a ceramic liner in the chimney (if they had one of those before, you don’t need to replace the liner, but chimney’s built before a certain time period were unlined, and if you switch to gas, it generates acidic compounds that would eat the mortar out). Not to mention if they switch from oil to gas (which I didn’t pick up if the old unit was gas or oil), that is expensive as well.
7k would be about right for a high efficiency unit, I think when I had mine done about 10 years ago it was 6500 or so.
No steam lines in our (or I suspect in Igloo’s) house - it should have been a simple swap of forced air gas heaters. However, the space where ours is positioned in the garage would not exactly fit the newer models. So it was $7k vs foregoing the promised $50 reduction of the monthly heating bill (9 mos per year; BFD!) plus $500 for a new blower motor assembly (which Mr. would have bought on Amazon for $150). We chose to forego the “savings” and paid the dude $500.