howardpike

The Airco/Olsen WBS2 is a naturally-aspirated, downflow gas furnace. It is only approved for an upright installation in the orientation that it is currently working; that is, with the blower at the top. There is no way that it can be mounted horizontally. Besides being contrary to the specifications on the Rating Plate, it would be extremely dangerous. The WBS2 is an old furnace design with no other installation options.

Jim, you are right, of course, but when this model was going through certification, the 12" x 16" x 1" filter was within a few square inches of the requirements for airflow. Because it was a downflow and air conditioning was so sparse up here, the supplied filter was only designed for the heat-only application. The manufacturer at the time could have upgraded the filter to a washable foam variant that on paper showed a greater airflow capacity than the fibreglass filter but was in reality denser and more restrictive. They/we chose to go with the custom-made filter plus the side filter in order to meet the rules. In the field, we regularly changed the filter to the single 12x16 fibreglass and have seldom (read, never) seen them plugging up between annual checkups. We monitor the temperature rise and find no issues with the filter change whatsoever. Even dirty filters are not putting the furnace anywhere near its limit point. The reduced filter size has had no negative effects for our customers. Those pleated filters, however, were never certified for use in any furnace back in 80's and 90's. I doubt if they are now. Unless they are watched closely and changed often, they will kill a perfectly good furnace. Hopefully, the furnace airflow is balanced with a dirty pleated filter in place. Ideally, the filter system is replaced with a wider version, complete with a bigger and better filter flame.

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.)

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.

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.

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.

Basically, yes. From the introduction of the "steel burners" in the early '70's until the last "Airco" was built in 1986 - the Highboys, Counterflows, and Lowboys; the standard and mid -efficiencies - whatever was built to burn natural gas with the steel burners, had the potential for the Airco Howl. The cast iron burners weren't affected.

Airco furnaces that were built from the early 1970's until 1985 used steel ribbon burners fabricated from slotted steel pipe and pressed venturi. They were great for natural gas but never worked well enough for propane. They howled. Gas burns, but not like the flame of a candle. As the gas (actually, the gas-air mixture) blows out of the burner, the flame runs down the gas, consuming as it goes. When everything is balanced, the flame consumes the gas at the same rate that the gas flows from the burner, and the flame appears to sit on top of the burner. However, on Airco's steel burner, the venturi effect was too efficient and drew in too much air, causing the velocity of the gas to exceed the rate of combustion. In effect, the flame would momentarily lift from the burner and then jump back onto it as the gas-air mixture further mixed with more air, moving it into the range for combustion. This is no big deal, as it happens intermittently on all furnaces. We all know that gas burner flames are erratic. The problem with the Airco steel burner was that it could be tuned - the air shutter opened up - to get the flame jumping at a regular frequency. And, to make matters worse, at a frequency that was in harmonic to the height of the heat exchanger. The flame would lift and jump back, sending a pressure wave up to the top of the HX, which would then reflect back, hitting the burner in time to augment a subsequent lifting/jumping of the flame. This quickly turned into a very loud trumpet blast that became known as the "Airco Howl". It is a minor problem that is easily caused by giving the burner too much air, and easily fixed by adjusting each air shutter closed, and then opening it until the yellow flame just disappears, PLUS a little bit more. Don't ever operate an Airco furnace with closed air shutters - it will soot up in a few hours of operation. The usual problem found in the field is the air shutter slowly increasing its opening over years of operation. It will then cause the Airco Howl on start-up when the burners are cold. The fix is to close each air shutter somewhat, while avoiding the yellow flame.

Thanks for the vote of confidence, John. I've got a new computer and a sick old one. Sort of lost TIJ through the transition.

Man, yours is a challenging problem. In 1958-59, the Airco furnaces were probably using the earliest version of the Robertshaw combination gas valve. If so, then you have a red button that needs to be pushed to get the pilot light lit and held. That old valve has known electrical issues with the contacts for the push button. These repeated nuisance-problems have made replacing these valves the only remedy. But perhaps it's something else. The problem is that there are virtually no mechanical problems that can be fixed by turning the power off then back on. It's got to be an electrical problem, but none that I'm familiar with. There just isn't enough information to diagnose this on-line. Sorry.

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.

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!

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.

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.

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.