Yet another furnace age question, Old Airco

[howardpike]

Hello Howard.

This Airco oil furnace is mounted horizontally in the crawlspace. Model 10-2H7, Serial 102-57. Can you tell the year? I know it is old. The age of the furnace can help us establish the age of the house.

The Serial Number is probably 1D2-57. The Model Number is too faded to be sure, but it may be 80-2HO (output 80,000 BTU, size 2, Horizontal, Oil). It's before my time at Airco. It certainly is an old machine with what looks like an Aero burner with a cast iron head. With the older pump, it can't be a retention head burner. Even the Rating Plate is ancient. The input is rated at 105,000 BTU with the .75 gph nozzle.

The last two numbers of the Serial Number refer to the manufacturing date: 5 is the month, 7 is the year. By 1977, the Rating Plates were a newer design, and the burners the retention head style. In 1957, the furnace should have had rounded corners. So, this must be a 1967 furnace. Even the controls suggest the 1960's rather than '70's.

I'm pretty sure that your furnace was built in May of 1967.

[Nolan Kienitz]

The link below goes to a database of decoding for Airco serial numbers.

Airco Serial Numbers

I use this site a lot for HVAC and W/H.

[John Kogel]

Hello Howard.

This Airco oil furnace is mounted horizontally in the crawlspace. Model 10-2H7, Serial 102-57. Can you tell the year? I know it is old. The age of the furnace can help us establish the age of the house.

The Serial Number is probably 1D2-57. The Model Number is too faded to be sure, but it may be 80-2HO (output 80,000 BTU, size 2, Horizontal, Oil). It's before my time at Airco. It certainly is an old machine with what looks like an Aero burner with a cast iron head. With the older pump, it can't be a retention head burner. Even the Rating Plate is ancient. The input is rated at 105,000 BTU with the .75 gph nozzle.

The last two numbers of the Serial Number refer to the manufacturing date: 5 is the month, 7 is the year. By 1977, the Rating Plates were a newer design, and the burners the retention head style. In 1957, the furnace should have had rounded corners. So, this must be a 1967 furnace. Even the controls suggest the 1960's rather than '70's.

I'm pretty sure that your furnace was built in May of 1967.

Thanks you, sir. I had the house dated as a '65 so 1967 it is.

[OnAir]

Hello,

Could anyone please supply info on my furnace? It looks old and if I had to guess I'd say it was from the mid 1960's (The house was built in 1965).

Brand: Airco

Model: 100-AGH

Serial: 9D-24

Manufactured in Vancouver British Columbia

Manufactured by: Mitchell Manufacturing Ltd.

I tried to use the website with the "database of decoding serial numbers", but I wasn't able to figure mine out.

[John Kogel]

Hello,

Could anyone please supply info on my furnace? It looks old and if I had to guess I'd say it was from the mid 1960's (The house was built in 1965).

Brand: Airco

Model: 100-AGH

Serial: 9D-24

Manufactured in Vancouver British Columbia

Manufactured by: Mitchell Manufacturing Ltd.

I tried to use the website with the "database of decoding serial numbers", but I wasn't able to figure mine out.

I get to reply ahead of Howard The Airco Guru. []

2 is the month, 4 is the year - 1964

Beatlemania!

The design output was 100 BTU/hr and stove oil was cheap.

[OnAir]

Thanks John. 1964 make perfect sense, but are you saying that it is an oil furnace? Is that what "AGH" stands for? If so, that's interesting as it currently runs on natural gas. Is it common to see furnaces converted from oil?

[howardpike]

Hello,

Could anyone please supply info on my furnace? It looks old and if I had to guess I'd say it was from the mid 1960's (The house was built in 1965).

Brand: Airco

Model: 100-AGH

Serial: 9D-24

Manufactured in Vancouver British Columbia

Manufactured by: Mitchell Manufacturing Ltd.

I tried to use the website with the "database of decoding serial numbers", but I wasn't able to figure mine out.

With a modicum of fear that I'll give John all my secrets...

The manufacturing date is indeed February 1964. But the AGH is "A"irco "G"as "H"ighboy. It probably has three cast iron burners. It's life expectancy is unknown, for while Terasen will use photos of old Airco's to pitch their replacement programs, there has been NO failure pattern for the Airco Highboys. Sixty years is reasonable. The heat exchangers were amply wide and sufficiently tall to keep the flames well away from the metal. In a normal home, the Airco heat exchanger doesn't rust or crack. The 100-AGH is the smallest input in the Airco three burner furnaces, so it's the furnace with the longest life-expectancy. The furnace had a belt-drive 1/4 HP (was originally a 1/6 HP) motor. It should use a 24 volt thermostat.

It's a great furnace, and very reliable. However, it was rated at 80% efficiency in those days - that's steady-state efficiency. But, that was the reality plus 5%. The same model by 1986 was only 76% steady state and figured to be about 55% AFUE - Annual Fuel Utilization Efficiency - over the year.

When Airco came out with the Airco Turbo at 81% AFUE in 1981, several tests were done to compare the new mid-efficiency's to the old standard-efficiency furnaces (what you have). The average savings was 23% over the winter. That means that if you were to change out your Airco and put in a new High Efficiency furnace (which our government requires for new installations), your savings should be about 35%.

And yet, you have one of the most reliable furnaces ever built.

[Jim Katen]

. . . That means that if you were to change out your Airco and put in a new High Efficiency furnace (which our government requires for new installations), your savings should be about 35%.

And yet, you have one of the most reliable furnaces ever built.

Even with 35% in fuel savings, it might be a poor economical choice to replace that furnace. The new furnace might only last 15-20 years and have to be replaced yet again - and new furnace installations will only get more expensive with time.

He would be better off to accept the low efficiency of the furnace, which will last, essentially, forever, and put money into making his home more efficient in other ways.

[howardpike]

Even with 35% in fuel savings, it might be a poor economical choice to replace that furnace. The new furnace might only last 15-20 years and have to be replaced yet again - and new furnace installations will only get more expensive with time.

He would be better off to accept the low efficiency of the furnace, which will last, essentially, forever, and put money into making his home more efficient in other ways.

Jim, I agree with you. It's nice to see another westcoaster who recognizes the realities of our mild climate.

When Airco brought out their mid-efficiency, it was a tweaked version of that old AGH workhorse. Even at only 23% savings, the payback was excellent IF the old furnace had to be replaced anyways. The new furnace would last long enough for the customer to recover all of their up-front investment and put money in their pockets within 9 years. The high efficiency furnaces would never pay off - their high costs and low life-expectancies would have them being replaced before any payback was realized.

We are still seeing lots of Airco's up here that were installed in the late 1950's. They are not deteriorating. They are looking much the same as they did when we started looking at them in the 1980's. There are some screws to retighten and some gaskets to inspect, but they are incredible workhorses. Most of the parts - motor, gas valve, transformer, fan & limit, pilot - are still available and cheap.

Why invest $5,000 in a new furnace to save $400 a year, and then replace $1,500 worth of parts and labour before it reaches 12 years old? It makes no sense to me. (But, it did to my best friend, who, unbeknownst to me, had his furnace ripped out by a fast-talking pitchman with a squealing gas detector and all sorts of rebates. When all was said and done, $3,000 became $5,000; he's complaining that his furnace isn't working properly; and our friendship is strained. Sure, I was very busy, but never so busy that I'd not help my buddy.)

KEEP THOSE OLD AIRCO HIGHBOYS (the tall green furnace with the filter at the side at the bottom). It will probably outlast all of us!

[John Kogel]

Sorry, OnAir. That remark about oil was just a general comment from an islander. No natural gas here until 1990 when they laid the pipeline across the Strait.

Thanks Howard.

There is a version of that furnace that is a downdraft style. Return air enters the upper end and is drawn down through the heat exchanger. That struck me as a good design but what say you? Is there more condensation on the heat exchanger or less?

[howardpike]

Sorry, OnAir. That remark about oil was just a general comment from an islander. No natural gas here until 1990 when they laid the pipeline across the Strait.

Thanks Howard.

There is a version of that furnace that is a downdraft style. Return air enters the upper end and is drawn down through the heat exchanger. That struck me as a good design but what say you? Is there more condensation on the heat exchanger or less?

John, two points. First, I know that Victoria had manufactured gas for quite some time, and I think Nanaimo did, as well. Airco was selling their natural gas furnaces, right up until the gas line arrived from the mainland.

Second, about the downflow, or "counterflow" furnaces; the Airco "ACF" or "AGCF", where "CF" stands for counterflow. Well, that is a more efficient furnace but not by much. As for longevity; they just don't have it. The coldest house air is blasting on the portion of the heat exchanger that has the coldest flue gases. Condensation occurs every time any furnace starts up, but on the counterflow, it lasts just a little bit longer, and that's enough to kill the furnace. Airco used to put caps on top of the heat exchangers to reduce the thermal gradient, and I think I remember them "painting" the inside at the top with a sort of metal primer, but that stopped when they realized that they were getting almost 30 years of service out of the ACF's, instead of the industry average of 17 years in the mid-80's. The change had virtually no affect on the life-expectancy. The Airco's, the Furnaceman's, the Intercity's, and the Lennox's with the tall, wide heat exchangers, were some amazingly long-lived furnaces.

[OnAir]

. . . That means that if you were to change out your Airco and put in a new High Efficiency furnace (which our government requires for new installations), your savings should be about 35%.

And yet, you have one of the most reliable furnaces ever built.

Even with 35% in fuel savings, it might be a poor economical choice to replace that furnace. The new furnace might only last 15-20 years and have to be replaced yet again - and new furnace installations will only get more expensive with time.

He would be better off to accept the low efficiency of the furnace, which will last, essentially, forever, and put money into making his home more efficient in other ways.

Jim / Howard,

Absolutely, I agree. Better to spend the money on improving the house's efficiency, thereby resulting in a lower fuel bill each month. You guys are right, it's a simple, reliable furnace that should run for many more years.

[OnAir]

Sorry, OnAir. That remark about oil was just a general comment from an islander. No natural gas here until 1990 when they laid the pipeline across the Strait.

No problem John, although I was beginning to have visions of having to locate and dig up a buried oil tank.

By the way, thanks to all of you for your help. You guys have been very helpful.

[John Kogel]

Thanks Howard. Counterflow is no-no, got it.

Yes, Victoria had a coal gas plant but you must be an old fart. That was before the Great War. []

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Built in 1860. I have seen the old gas pipes in some century old houses.

[delislej]

I have an Airco Model AH-75 serial 1F3-97 or IF3-97. Any idea on age?

Name plate appears to be a label and not metal, and has more information than the 60's ones I see here. The house was built in 1967 I believe, and the furnace looks original.

[howardpike]

I have an Airco Model AH-75 serial 1F3-97 or IF3-97. Any idea on age?

Name plate appears to be a label and not metal, and has more information than the 60's ones I see here. The house was built in 1967 I believe, and the furnace looks original.

The furnace was indeed built in September of 1967, so it is the original.

As you've read in the previous posts, this model of furnace has an excellent life expectancy - 60 years. And, it is trouble-free. The chance of you have a life-ending failure is remote, but if you've got the money and are investing in the future of the house, then it's as good a time as any to upgrade.

However, if you are thinking of replacing it because "it's old", or "it's got a crack in it", or "it's very rusty", then get a second opinion.

Other than a hole in the heat exchanger or a burner damaged beyond repair, everything else on the furnace is a fairly low cost and straight-forward repair.

[delislej]

I have an Airco Model AH-75 serial 1F3-97 or IF3-97. Any idea on age?

Name plate appears to be a label and not metal, and has more information than the 60's ones I see here. The house was built in 1967 I believe, and the furnace looks original.

The furnace was indeed built in September of 1967, so it is the original.

As you've read in the previous posts, this model of furnace has an excellent life expectancy - 60 years. And, it is trouble-free. The chance of you have a life-ending failure is remote, but if you've got the money and are investing in the future of the house, then it's as good a time as any to upgrade.

However, if you are thinking of replacing it because "it's old", or "it's got a crack in it", or "it's very rusty", then get a second opinion.

Other than a hole in the heat exchanger or a burner damaged beyond repair, everything else on the furnace is a fairly low cost and straight-forward repair.

Thanks!

[vmoss]

I can confirm what other fellow poster stated... 1967 - 1969 would definitely be the age rage for that Airco Model [:-graduat

If you have any other HVAC questions, pm me or ask them here and will be more than happy to help!

[Calab]

Trying to determine the age and model of our old AirCo furnace. The Serial Number link doesn't seem to cover my model so I'm asking here...

Model: HBS2-100/90

Serial: CB-02108

No issues with the furnace yet - knock on wood... but we are considering replacing or upgrading to get A/C.

[howardpike]

Hey Calab,

By the time this furnace was manufactured I had left DMO/Airco and was working for myself. The HBS2-100/90 was a great little workhorse. It was fired at 100 MBTU at sea level, but where you live, near Calgary AB, it came out of the box derated to 90 MBTU. It is a standard efficiency, draft-hooded furnace, rated at 76% steady state efficiency, but only about 55% to 60% over the season (AFUE).

The serial number is a nuisance. The letters are the month and year or year and month. I called a friend who worked at the plant in Engineering in those days and he "remembers" that it was month then year. Hmmm. It really doesn't matter.

CB-02108... C = March; B = 1988; 02108 = the 2,108th furnace built that year, which makes sense as the plant would slow its production in the first quarter, making 800 to 900 furnaces a month, or around 2000 units by mid March. By 1989, standard efficiency furnaces were no longer being allowed, so...

Your furnace should have been built in March 1988; 28 years ago. That's a good life for the narrow Olsen-designed heat exchanger... a very good life. It would be a good time to upgrade. The best your furnace can be is 11 months younger. If you have the money, you can invest in greater comfort and efficiency without thinking that you are throwing away a perfectly good furnace. (My buddy and I are wondering how your inshot burners lasted so long.)

Thanks for the question and the excuse for me to contact my old friend.

[HeatherB]

I have an AIRCO WBS2-100/90 Serial # BJ-13080 and I can't seem to find what size filters it requires. Also, any information about the furnace and whether I should be replacing it would be greatly appreciated.

Thanks,

Heather

[Red89GT]

Hello

I am also looking for any info that can be provided on my Airco furnace. It is a downdraft furance from a home built in 1990

Model: WBS2-120

Serial: DD-03133

heres a pic or the label showing serial and model number: https://goo.gl/photos/9Ppqhv9uYhMiewmR6

[howardpike]

I have an AIRCO WBS2-100/90 Serial # BJ-13080 and I can't seem to find what size filters it requires. Also, any information about the furnace and whether I should be replacing it would be greatly appreciated.

The WBS2-100/90 is a three burner counterflow/downflow furnace. Its filters are located through the blower compartment at the top of the furnace. Make sure that the furnace power switch or circuit breaker is turned off. Remove the upper door by lifting up and out at the bottom. Remove the screw holding the small panel to the right of the chimney; again, up and out. This gives you full access to the two filters.

One filter is a custom-made 10" x 16" x 1" disposable fibreglass filter that lays horizontally on two rails above the blower. It is pushed against the left side of the furnace when properly installed. The other filter is a 15" x 20" x 1" standard disposable fibreglass filter that is fitted vertically in a rail just above the blower partition (compartment base) and leaned towards the blower, contacting the upper filter at the top.

Many of these furnace models have had their upper filters replaced with a 12" x 16" x 1" standard fibreglass filter that is often available at the smaller hardware stores. The 15x20 filter is not used as the 12x16 provides a complete seal at the top of the furnace. (Just as if it was planned.)

Replace the panels and turn the power back on.

The WBS2 is a reliable furnace with quality parts and a good design. It is a "standard efficiency" model with a rated AFUE (Annual Fuel Utilization Efficiency) of 55%. However, if the furnace is in a dedicated furnace room off the garage, as many are here in the Lower Mainland, the off-time losses are considerably reduced. This furnace is one worth keeping until the heat exchanger shows signs of rusting and pitting at the top of the clamshells.

[Jim Katen]

Many of these furnace models have had their upper filters replaced with a 12" x 16" x 1" standard fibreglass filter that is often available at the smaller hardware stores. The 15x20 filter is not used as the 12x16 provides a complete seal at the top of the furnace. (Just as if it was planned.)

I always hate to see that done because it cuts the filter surface area in half (less than half). If they're using a pleated filter with fine media in it, that reduction in surface area can throw up a high static pressure across the filter and cause the furnace to run hot.

[howardpike]

I am also looking for any info that can be provided on my Airco furnace. It is a downdraft furance from a home built in 1990 Model: WBS2-120 Serial: DD-03133

The WBS2-120 is the same design as the WBS2-100/90 which HeatherB asked about. The WBS2-120 has one more burner (total of 4) and so the top filter is wider.

The top filter is a 12" x 16" x 1" standard fibreglass filter.

The (right hand) side filter is a 15" x 20" x 1" standard fibreglass filter.

The WBS2-120 is a good furnace with a reasonable life expectancy... a little longer than the smaller WBS2-100/90.

Turn off the power and change the filters regularly (and long before you can't see through them). Vacuum the furnace out now and then, being careful not to suck out the pilot flame (though learning how to relight the pilot has other benefits). Have a furnace repair and maintenance technician have a good look at it every few years, especially have them remove the drafthood and look for pitting rustspots in the tops of the heat exchangers. But, be careful with who you get. Too many furnace installers find damage, holes and cracks where none exist. Today's gadgets and test instruments can show a leak that comes from spillage from the drafthood opening and loosely-fitted return air ducting - installation problems that can be fixed and have no bearing on the health of the furnace. Too often, the "leak" is background contamination and simply reveals a poor test procedure.

(I saw your photo of rating plate, but it just verified the information that you already provided. It was helpful.)