Yet another furnace age question, Old Airco

[dude99]

I just stumbled across this forum and have been reading through it. I have to say I find the steam systems fascinating, as well I'm impressed by the level... anyways

My house currently has an Airco Furnace in it that we're looking at replacing and I'm curious how old it is. Its serial number scheme isn't listed in any of the documents I've found on this site.

Brand: Airco

Model: AH-90

Serial: U2-10

Manufactured in Vancouver British Columbia

Manufactured by: Airco Products ltd.

Any Guesses?

[Mark P]

I found an AHMS-90 by Airco manufactured in 1987 and AHCS2-90 manufactured in 1988. As a matter of fact everythng I see by them was manufactued in 1987-88

[dude99]

Thats actually newer than I would have guessed, thanks.

[John Kogel]

Hello, dude. Airco made furnaces under license to one of the bigger companies, Lennox, maybe, for quite a few years dating back to 1970 I believe.

Best suggestion I have is to write the new owners for info.

http://www.olsenhvac.com/contact_us.asp

Around here, an oil furnace will often have been installed when the house was built. So if you have the date of the Permit of Occupancy, that might be a clue.

Sometimes the date is stamped right on the blower motor, visible when you open the filter compartment. Mind you, the blower fan may have been changed.

[howardpike]

My house currently has an Airco Furnace in it that we're looking at replacing and I'm curious how old it is. Its serial number scheme isn't listed in any of the documents I've found on this site.

Brand: Airco

Model: AH-90

Serial: U2-10

Manufactured in Vancouver British Columbia

Manufactured by: Airco Products ltd.

Any Guesses?

Your AH-90 was built in January of 1970. The "U" in the serial number stands for "Upflow"; the "2" is a "2 Rad" (2 burners); the "1" is "Month 1 = January"; and the "0" is the "Year 0 = 1970". The model number is younger than 1960 - it would have been "UGH" back then. And, the serial numbers had 2 digit years by 1980.

FYI - Your furnace has a life expectancy of 50 years or more, but you should save 35% on your heating bill by upgrading to high efficiency. However, Airco's are pretty much trouble free and very reliable, even at 55 years old, as some now are.

[howardpike]

Hello, dude. Airco made furnaces under license to one of the bigger companies, Lennox, maybe, for quite a few years dating back to 1970 I believe

Airco started building "Airco" gas furnaces under licence (that's Canadian for "license") in 1956. Basically, they were buying the heat exchangers from an American manufacturer (probably Armstrong) until they could build their own "unique" clamshells in 1957 or '58. By unique, I mean identical, until they were forced to make a small dimensional change to avoid legal problems in the early '60's.

This heat exchanger was used in the Highboy, Counterflow and Console models (AGH/AH; AGCF/ACF; and AGC/AC) from 1956 through 1985/86.

[hausdok]

50 years?

Should I be putting on hip waders? I haven't seen very many gas furnaces that can last much longer than 20 to 30 years let alone 50+.

ONE TEAM - ONE FIGHT!!!

Mike

[howardpike]

Should I be putting on hip waders? I haven't seen very many gas furnaces that can last much longer than 20 to 30 years let alone 50+.

Mild winters and over-built furnace designs. They had about 1300 square inches of heat exchanger surface area for 45,000 BTU. That means very little heat stress in the upflow version. And, there were no sharp breaks or deep draws. The heat exchanger was screwed to the inner front panel. No asbestos. A stress-free design and a running-efficiency of 75%, even after 30 years. Of course, they had drafthoods, which dropped the seasonal-efficiency quite a bit depending on the installation.

Counterflows rusted out at about 30 years. I've only seen one rusted out highboy and it was a mid-efficiency that had every safety interlock over-ridden by the homeowner to keep it working for years after the brick chimney got partially-blocked. It didn't kill anybody, but the wiring melted and shorted out the transformer, killing the furnace.

Great furnaces - service tech friendly, too.

[kurt]

Some of those old monsters can last "forever"; no stress, huge surface area, standing pilot keeps things dry in summer, etc. There's not much to break. They don't hit their rated efficiency, though. 75% is wishing, don't ya think?

[AlanC]

I came across this forum searching for information regarding my father's old Airco Furnace. It stopped working today and it appears at first glance that the blower motor is not working. I plan on disassembling and removing the motor tomorrow but was wondering if anyone here had any thoughts on getting a replacement. Not sure where to go or if they would even make a replacement motor. This is the original furnace that was installed when my father built the house in 1971. It's never been replaced it has run flawlessly for the entire time.

I did think about replacing the entire furnace but my father is almost 90 years old and it's clear that at this stage in his life, spending so much on a high efficiency furnace may not be in his best interests.

Thoughts?

Thanks

AlanC

[Marc]

I came across this forum searching for information regarding my father's old Airco Furnace. It stopped working today and it appears at first glance that the blower motor is not working. I plan on disassembling and removing the motor tomorrow but was wondering if anyone here had any thoughts on getting a replacement. Not sure where to go or if they would even make a replacement motor. This is the original furnace that was installed when my father built the house in 1971. It's never been replaced it has run flawlessly for the entire time.

I did think about replacing the entire furnace but my father is almost 90 years old and it's clear that at this stage in his life, spending so much on a high efficiency furnace may not be in his best interests.

Thoughts?

Thanks

AlanC

Just take it to a local HVAC wholesaler and ask them to match the motor dimensions, shaft dimensions, speeds, voltages, horsepower, etc to something in their stock. They can often find something that'll work.

Bring the whole blower, not just the motor.

Marc

[howardpike]

This is the original furnace that was installed when my father built the house in 1971. It's never been replaced it has run flawlessly for the entire time.

The motor is either a 1/6 or 1/4 HP GE Belted Fan Motor. It could be a 1/4 HP Emerson, but for whatever it was, the replacement motor is the Emerson 840CV. There are alternatives, but this motor is identical to the originally certified model. It's quiet and is a straight-forward replacement. Be sure to get a "Belted Fan and Blower Motor" as it has the rubber noise isolating mountings that the "Utility" motors don't have.

Phone the big box hardware stores, get the 840CV and avoid the problems. The 840CV is very common in the Lower Mainland (at least among the heating dealers - it's the "right price") and should be readily found after a few calls.

[AlanC]

Thank you gentlemen for the prompt response and valued advice.

I went to my father's house to remove the motor and blower unit this morning. When I arrived I turned the furnace on and it fired up immediately for a few minutes as usual. Then suddenly the motor kicked in and began working. This threw me off and I was pleasantly surprised but also concerned that if the problem re-occurred that I would have no idea as to the actual problem. The motor sounded fine and there was no strange sounds coming from it or the blower unit.

My father who is a month away from being 90 was relieved and we went upstairs to talk about old war stories over a cup of coffee. Long story short, the furnace went off after reaching the proper temperature and when it came time to kick back on, the burners ignited but no motor or blower action. So, it looks like I will need to call someone in to determine what the problem is. I checked the wiring for corrosion and it all looks good. I lubed the motor shaft and also the blower motor shaft and bearings and the unit motor comes on intermittently.

Anyway, your help was appreciated. Will give a tech a call tomorrow to see what the problem may be.

thanks

Alan

[AlanC]

Howard,

I just noticed that you are in Coquitlam. Are you a furnace service tech?

[Marc]

If this motor has a capacitor on it, you might replace it and see if that helps. They're not expensive but often give trouble.

Marc

[John Kogel]

Alan, if you click on Mr Pike's name on one of his posts you will go to his profile. From there you can send him a message (PM). His company name is there as well. Chimo Furnace Service. 604-936-5593

The fan motor may be just fine. There is a sensor in the furnace that switches the fan on when the correct temperature is reached. That may be faulty. Or there could be a bad connection. A technician will apply power directly to the motor and see if it starts up.

[howardpike]

I went to my father's house to remove the motor and blower unit this morning. When I arrived I turned the furnace on and it fired up immediately for a few minutes as usual. Then suddenly the motor kicked in and began working. This threw me off and I was pleasantly surprised but also concerned that if the problem re-occurred that I would have no idea as to the actual problem. The motor sounded fine and there was no strange sounds coming from it or the blower unit.

Alan,

The motor has what BC Hydro used to call "a flat spot". It doesn't have one but as the centrifugal switch gets old, it starts to stick in the "run" position. It looks as if the motor has some magic spot where the motor just won't start without some persuasion. Sometimes that persuasion is in the form of the motor overheating, sometimes it's the vibration of overheating, and sometimes it's just being switched off for a while. When it's bad enough, it's a good whack with a hammer on the side of the end bell.

Anyway, the centrifugal switch switches the motor between the start winding and the run winding. When it's old and dirty, it hangs up until something moves it back to the starting position... persuasion.

In any case, the motor is probably at the end of its useful life. There's a simple way to tell. Use the "Auto/Manual" switch on the Junction Box (up and behind the gas control valve) to turn on the motor. Allow it to run for a minute, then turn it off. As it slows down, you'll hear a click as the centrifugal switch switches to "off". If the motor is almost stopped when you hear the click, then it's hooped. You can also turn the motor right back on when it stops. If you hear an "uhhhhnnnn" (low buzz) before it starts, then it's hooped.

Sometimes a good blast of WD-40 in the back end will give you several days to months out of the motor, but the motor is probably finished.

Yes, we can help, but that's not the purpose for replying to your query. I worked for Airco for almost ten years and I know how reliable their furnaces are. They will last 40 to 60 years around here.

[Les]

seriously, I just love you Canadians - "hooped"? thought I knew everything!

[JohnFoster]

Your AH-90 was built in January of 1970. The "U" in the serial number stands for "Upflow"; the "2" is a "2 Rad" (2 burners); the "1" is "Month 1 = January"; and the "0" is the "Year 0 = 1970". The model number is younger than 1960 - it would have been "UGH" back then. And, the serial numbers had 2 digit years by 1980.

FYI - Your furnace has a life expectancy of 50 years or more, but you should save 35% on your heating bill by upgrading to high efficiency. However, Airco's are pretty much trouble free and very reliable, even at 55 years old, as some now are.

What year would an AGS-120, S/N 3K1-26 be?

Also AGS-80, S/N 2K1-B5. Probably both installed at the same time.

BTW they're in Coquitlam - public works on Austin Ave, maybe you've worked on them? I was going to recommend upgrading. Always seems a shame with things that have lasted so long.

[howardpike]

What year would an AGS-120, S/N 3K1-26 be?

Also AGS-80, S/N 2K1-B5. Probably both installed at the same time.

Airco's AGS (Airco Gas Suspended) Horizontal Furnaces are problematic. Both the AGS-80 and the AGS-120 are the lower input versions of the AGS-100 and AGS-140, respectively, but the date codes make them at best circa mid-70's, and possibly mid-60's.

These models are under a great deal of thermal stress, so you should look for cracks in the top plate of the burner box. What we found were hairline cracks that propagated 90 degrees to the clamshell welds and grew up into the heat exchanger. You can remove the burners and take a look, or with the furnace cold, turn on the fan and run a burning match under the welds on both sides of the burner box. If there's a crack, the flame will be blown away.

They are very old and are indeed due for replacement, and with a little work, you can prove it.

[hausdok]

Howard,

Home inspectors aren't allowed to remove burners and such. I think I've only seen one or two Airco units in 16+ years, so I can't picture what you're talking about. I don't think there is any way we could do what you're talking about without some kind of disassembly.

The typical way we'll inspect a heat exchanger is with a mirror, if we can, to try and look for visible cracks. Sometimes some of us remove a temperature sensing unit so we can peer into the box and feel around with a fingertip - there are some Carrier units sold by Carrier and BDP where this frequently reveals cracks; but most inspectors won't do that because it's considered to be "invasive" and is beyond the mandate.

It's more common for us to run the furnace and observe the flame and wait for the fan to come on. If there are cracks in the exchanger the second the fan comes on and pressurizes the air around the heat heat exchanger that air pushes through the cracks in the exchanger and substantially changes the appearance of the flame. Is there any reason that wouldn't hold true for an Airco unit? What kind of disassembly are we talking about for your match method?

ONE TEAM - ONE FIGHT!!!

Mike

[howardpike]

The match method does require removing the Flame Shield/Secondary Air Baffle. It's meant for a furnace tech. Even using a mirror would require removing this part. House inspectors need to be very careful about removing anything. There are major liability concerns.

The AGS Horizontal Gas Furnace is quite unique. The burner face is about a half inch below the bottom of the clamshell. It's too high to react to a leaking crack. And, because owners don't get annual inspections by furnace techs anymore, we've got the catch the crack before it starts opening up enough to be dangerous.

By the way, Airco never certified their furnaces south of the line, so there won't be any AGA approved Airco furnaces in Washington State. However, I'm sure that didn't stop thrifty American shoppers from slipping in a cheaper Canadian furnace without a permit.

[dabil]

Can someone give me more information about my Furnace

Airco products ltd

AGS-80 serial K2-682

its propane

[howardpike]

AGS-80 serial K2-682 - its propane

Your AGS 80 was built in June of 1982. That makes it 30 years old, and nearing the end of its effective life. The typical heat exchanger failure for this unit is hairline cracks at the top of the burner compartment in the top plate where it is welded to the clamshells. The crack seems to start at the bottom weld of the clamshell, then grow up and down into the burner compartment. Once in the top plate, they open up enough to allow a little air flow from the house into the heat exchanger when the fan is on. They are hard to spot without removing the burners.

[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.

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