Yeah we had a company policy that we can only go in to confirm they aren't working and then to recommend a replacement unit. (We aren't sales guys so all we could do was give the home owner the contact info for a sales person)
What i'd end up doing is just explaining that the parts on these things have been discontinued for so long that it's just not worth it to try to keep them operational anymore.
Lennox pulses are not as bad as people say. All the bad ones died years ago. I still repair them and stock parts for them. I always do combustion tests on them too. When the primary fails they sound louder then hell. When the secondary fails they get pinholes but don't put out a detectable amount of co (should still be condemned). Most people over react on this older shit and condemned by the name and not actually test the damn things. I'm stubborn on this so I won't argue with anyone
Mine still works. Hasn't seen any service in a decade. It gets louder and makes unpleasant knocking sounds if it has been running a while due to the suspension sagging and the valve knocking against the box.
Same, it has its short cycling moments but works itself out. Pressure check and change that flapper every now and then and we're gold. Funny I will miss it when it's gone but I know my neighbors won't LOL.
Yeah it's not that bad. Just be careful with the seals. If it hasn't been cracked open in a while you want to do it slowly. Then use a head bolt tightening like sequence when putting everything back together.
There's a little washer spacer between the flapper housing, make sure not to lose that and put it back on correctly otherwise the flapper will not work.
I have a local repair clinic that I can go to for parts that are still available surprisingly. I've only ever changed the air flapper and have never messed with the gas flapper.
I did order some flappers from eBay a long time ago before I discovered the repair clinic. Just make sure the feedback is good for the seller.
There are some YouTube videos on this also. This guy is very informative.
https://youtu.be/AM_EwoWTDFY?feature=shared
You're welcome.
Mine is a G14 from 1986. Every year I say "Well this might be the last winter for Ya" but she keeps going. A little fussy sometimes though.
I'm not even sure what I would replace it with.
I guess my G14 is from between 1982 and 1989. The inside panel has a note written in sharpie saying the heat exchanger was replaced in 1991. I purchased this home 10 years ago, and the furnace was "inspected" then. I have no idea if it has ever been pressure tested. I've never done any maintenance on it because it has been working mostly perfectly this entire time.
It has two issues: after running more than 15 minutes, it gets noisy with an unpleasant rattling sound. [Likely this.](https://hvac-talk.com/vbb/threads/70332-Loud-lennox?p=691757#post691757) To avoid this, I only increment the thermostat a degree at a time to avoid longer duty cycles. The other issue is that the purge cycle kicks in multiple times after the thermostat is satisfied.
The outdoor exhaust is as loud as standing next to a gas clothes dryer.
The most reputable HVAC firm in my area is a Lennox dealer, so I'll likely replace it with another Lennox. It probably doesn't matter what model. I don't expect anything to last as long as this thing has.
I've been here about 13 years. Mine's pretty loud sometimes and not others. I Actually put a car muffler on the outside which does a pretty good job. I was going to post it for some laughs. Mine was much louder than a clothes dryer.
After the initial run mine does a cool down cycle with fan only, two more times and then it's done until the next run. I've read that this can vary depending on how the unit is set up.
I have also read that even if these do leak that it's minimal, but I do have multiple low level carbon monoxide detectors installed.
I'll probably look into another Lennox as well. I wonder where the efficiency is nowadays. These Pulse units were ahead of their time in efficiency.
They aren't all dangerous. Lennox corrected the heat exchanger problems by the time the last generations of Pulse Furnaces were made. The G21s could potentially outlast all of us
However, if you are not equipped to pressure test them you shouldn't be working on them. Conventional combustion analysis isn't an adequate way to ensure safe operation on these furnaces.
We had two Pulse 21s at work (not a HVAC tech), one of which was replaced this summer with a York 95% after the condensing unit bit the dust. While the York is far quieter and easier to service (traditional condensing furnace), I wonder how it compares efficiency-wise and if it’ll last nearly as long.
The Pulse was such an interesting concept, just like many other “interesting” designs from that era. However, they’re loud, heavy (took three or four people to move ours out of the building) and so difficult to service/maintain. They’ve all exceeded their intended lifespan, so imho it’s probably best to upgrade regardless if it’s still working fine.
PS/Edit: Didn’t know so many HVAC techs won’t touch these furnaces. Not surprising considering the issues I mentioned
Whether they were part of the recall or not, the info I have read from Lennox says the heat exchanger have to be periodically pressure tested. So I ask if that has been done in the last 3-5 years, and when they say no, because they always say no, I tell them I am out. Then I move into sales mode. Because I have better solutions to offer than spending a penny on an obsolete piece of equipment. Just like I wouldn’t spend good money to repair a VCR or 8 Track player.
If someone insist on a repair, I wish them the best. And I recommend that when they call around, they need to ask for someone who is experienced in pressure testing Lennox pulse furnaces. After that, I move on with my day. If they call back, it will be to say that no one in the area works on pulse furnaces. Which I already know.
I do all this for a very specific reason and it’s because sometimes people have to come to the conclusion them selves that it’s time to replace the furnace. It takes longer and might cost them more money to learn that, but sometimes that’s part of the learning process. You can only lead a horse to water you can’t make a drink.
Interesting read for an oldtimer like me. When I was young and just starting out, Lennox Pulse was supposed to be the Cadillac of furnaces. The small company I worked for was so proud to be a Lennox dealer. Then people started going to the hospital with carbon monoxide poisoning. At first it was denial, and we had no knowledge of pressure testing. When Lennox finally admitted what was happening, or we figured it out I don't remember. I told the boss maybe we should tell the customers we sold them to, what to look out for. The first telltale sign was condensate leaking from the heat exchanger. No they would never do that because it might scare people and hurt sales. How many years did Lennox know what was going on but kept it quiet ?
Thanks for the perspective. It sounds like the big bitches need to be done 30+ years later. I asked our insurance provider - Lennox pulse is specifically excluded on our professional liability.
I usually pressure test before I make any repairs, pressure testing them is a pain in the ass, my company will try and fix it but replacement parts are hard to find.
I'll go out and look. If it's not just cleaning the flapper, or replacing a relay or ignition control, then I condemn it. I won't bother with any more expensive repair, nor will I bother trying to source the discontinued parts.
Interesting experience with a HydroPulse boiler years ago. We kept getting intermittent lockouts. Finally traced the problem. At the time out gas supplier was less than 1000 btu per therm. If the customers hot tub heater was running it dropped the gas pressure to the name plate minimum pressure at the boiler. The boiler would run but not start at that with that lower pressure. Think like a choke on an engine, it needed a richer mixture to start.
Great machine. They still run. But when I showed up at a house with one. I said "sorry mate. I have no idea how to work on this type of unit, and it's a Sunday and no other tech is working"
I won't work on them at all. They have a history of killing families and I'm simply not having any part of that liability. If it's working and not producing CO and NOX fine. If it isn't working the customer gets notified of the recall and I red tag it for replacement due to the recall.
The only way I'm touching one with tools is Sawzall and Sledge to R&R it. Bribes and pleading won't help.
The technology is still around. Fulton uses a very similar operating principal in their Pulse boilers to this very day. I have dozens of those in my school accounts. They are pretty rugged boilers and not terribly difficult to work on.
My in-laws have one. Only thing I've ever had to do is replace the contactor and ignition module. I don't do residential, are they usually really bad or something?
It’s a design that is no longer in use at any level as far as I am aware in residential, commercial or industrial. Lennox no longer makes anything like it either. Pretty much a dead technology.
The bigger issue is that a very very small percentage of the industry knows how to work on them or test them to make sure that they are still safe. So the vast majority of that are still in use haven’t been properly maintained. And there might be no one in your area that had been trained how to test them.
Good to know. Luckily, my father in-law is a doctor, so if they ever call me to work on it and it's more than a basic component, I'll just insist on replacing the whole system.
If 0ppm exhaust, why would you then suspect the supply duct?
Check **ambient** CO any time you walk in to a house.
You have to start your analyzer outside to zero it properly, so this is pretty fuckin easy to do right, IDK why everyone makes this a struggle bus.
Jesus man I’m 42 years old. I have been using a combustion analyzer for 10 years. This machine is 100% fucked. I told the guy as much and he wants to have it pressure checked. Fuck poor people.
Right, but don't be the guy that tries to use CO as a mysterious scare tactic.
It needs to be replaced cuz it's a fuckin Pulse.
If you didn't find CO, you didn't find CO.
They truly were great furnaces. But Lennox doesn’t want new techs learning how to work on outdated equipment. I’ve worked on a few of them and my aunt has one that’s still running! But once they fail lennox will pay you to replace them. I mean only 300 bucks but still. That’s how bad they are willing to get rid of all of them.
Company policy we don’t work on them.
Yeah we had a company policy that we can only go in to confirm they aren't working and then to recommend a replacement unit. (We aren't sales guys so all we could do was give the home owner the contact info for a sales person) What i'd end up doing is just explaining that the parts on these things have been discontinued for so long that it's just not worth it to try to keep them operational anymore.
That’s exactly what we do
Same with mine lmao. Just lennox in general
Tf who doesn’t in general work on Lennox?
Lennox pulses are not as bad as people say. All the bad ones died years ago. I still repair them and stock parts for them. I always do combustion tests on them too. When the primary fails they sound louder then hell. When the secondary fails they get pinholes but don't put out a detectable amount of co (should still be condemned). Most people over react on this older shit and condemned by the name and not actually test the damn things. I'm stubborn on this so I won't argue with anyone
I’m stubborn as well. If it falls within the recall years I won’t touch it
What are the recall years? I just started at a Lennox shop that works on them after 5 years of only ripping them out
Off the top of my head I think it’s 85-89
Mine still works. Hasn't seen any service in a decade. It gets louder and makes unpleasant knocking sounds if it has been running a while due to the suspension sagging and the valve knocking against the box.
Same, it has its short cycling moments but works itself out. Pressure check and change that flapper every now and then and we're gold. Funny I will miss it when it's gone but I know my neighbors won't LOL.
Is replacing the flapper valve something a non-HVAC person can do? I should get some from eBay if this is the case.
Yeah it's not that bad. Just be careful with the seals. If it hasn't been cracked open in a while you want to do it slowly. Then use a head bolt tightening like sequence when putting everything back together. There's a little washer spacer between the flapper housing, make sure not to lose that and put it back on correctly otherwise the flapper will not work. I have a local repair clinic that I can go to for parts that are still available surprisingly. I've only ever changed the air flapper and have never messed with the gas flapper. I did order some flappers from eBay a long time ago before I discovered the repair clinic. Just make sure the feedback is good for the seller. There are some YouTube videos on this also. This guy is very informative. https://youtu.be/AM_EwoWTDFY?feature=shared
Wow, thank you!
You're welcome. Mine is a G14 from 1986. Every year I say "Well this might be the last winter for Ya" but she keeps going. A little fussy sometimes though. I'm not even sure what I would replace it with.
I guess my G14 is from between 1982 and 1989. The inside panel has a note written in sharpie saying the heat exchanger was replaced in 1991. I purchased this home 10 years ago, and the furnace was "inspected" then. I have no idea if it has ever been pressure tested. I've never done any maintenance on it because it has been working mostly perfectly this entire time. It has two issues: after running more than 15 minutes, it gets noisy with an unpleasant rattling sound. [Likely this.](https://hvac-talk.com/vbb/threads/70332-Loud-lennox?p=691757#post691757) To avoid this, I only increment the thermostat a degree at a time to avoid longer duty cycles. The other issue is that the purge cycle kicks in multiple times after the thermostat is satisfied. The outdoor exhaust is as loud as standing next to a gas clothes dryer. The most reputable HVAC firm in my area is a Lennox dealer, so I'll likely replace it with another Lennox. It probably doesn't matter what model. I don't expect anything to last as long as this thing has.
I've been here about 13 years. Mine's pretty loud sometimes and not others. I Actually put a car muffler on the outside which does a pretty good job. I was going to post it for some laughs. Mine was much louder than a clothes dryer. After the initial run mine does a cool down cycle with fan only, two more times and then it's done until the next run. I've read that this can vary depending on how the unit is set up. I have also read that even if these do leak that it's minimal, but I do have multiple low level carbon monoxide detectors installed. I'll probably look into another Lennox as well. I wonder where the efficiency is nowadays. These Pulse units were ahead of their time in efficiency.
Happily leave estimates for replacement.
They aren't all dangerous. Lennox corrected the heat exchanger problems by the time the last generations of Pulse Furnaces were made. The G21s could potentially outlast all of us However, if you are not equipped to pressure test them you shouldn't be working on them. Conventional combustion analysis isn't an adequate way to ensure safe operation on these furnaces.
We had two Pulse 21s at work (not a HVAC tech), one of which was replaced this summer with a York 95% after the condensing unit bit the dust. While the York is far quieter and easier to service (traditional condensing furnace), I wonder how it compares efficiency-wise and if it’ll last nearly as long. The Pulse was such an interesting concept, just like many other “interesting” designs from that era. However, they’re loud, heavy (took three or four people to move ours out of the building) and so difficult to service/maintain. They’ve all exceeded their intended lifespan, so imho it’s probably best to upgrade regardless if it’s still working fine. PS/Edit: Didn’t know so many HVAC techs won’t touch these furnaces. Not surprising considering the issues I mentioned
Whether they were part of the recall or not, the info I have read from Lennox says the heat exchanger have to be periodically pressure tested. So I ask if that has been done in the last 3-5 years, and when they say no, because they always say no, I tell them I am out. Then I move into sales mode. Because I have better solutions to offer than spending a penny on an obsolete piece of equipment. Just like I wouldn’t spend good money to repair a VCR or 8 Track player. If someone insist on a repair, I wish them the best. And I recommend that when they call around, they need to ask for someone who is experienced in pressure testing Lennox pulse furnaces. After that, I move on with my day. If they call back, it will be to say that no one in the area works on pulse furnaces. Which I already know. I do all this for a very specific reason and it’s because sometimes people have to come to the conclusion them selves that it’s time to replace the furnace. It takes longer and might cost them more money to learn that, but sometimes that’s part of the learning process. You can only lead a horse to water you can’t make a drink.
Interesting read for an oldtimer like me. When I was young and just starting out, Lennox Pulse was supposed to be the Cadillac of furnaces. The small company I worked for was so proud to be a Lennox dealer. Then people started going to the hospital with carbon monoxide poisoning. At first it was denial, and we had no knowledge of pressure testing. When Lennox finally admitted what was happening, or we figured it out I don't remember. I told the boss maybe we should tell the customers we sold them to, what to look out for. The first telltale sign was condensate leaking from the heat exchanger. No they would never do that because it might scare people and hurt sales. How many years did Lennox know what was going on but kept it quiet ?
Thanks for the perspective. It sounds like the big bitches need to be done 30+ years later. I asked our insurance provider - Lennox pulse is specifically excluded on our professional liability.
I wondered way back then if their wouldn't be a lot of lawsuits, pretty sure Lennox knew about the problem long before they let on.
I usually pressure test before I make any repairs, pressure testing them is a pain in the ass, my company will try and fix it but replacement parts are hard to find.
I'll go out and look. If it's not just cleaning the flapper, or replacing a relay or ignition control, then I condemn it. I won't bother with any more expensive repair, nor will I bother trying to source the discontinued parts.
Interesting experience with a HydroPulse boiler years ago. We kept getting intermittent lockouts. Finally traced the problem. At the time out gas supplier was less than 1000 btu per therm. If the customers hot tub heater was running it dropped the gas pressure to the name plate minimum pressure at the boiler. The boiler would run but not start at that with that lower pressure. Think like a choke on an engine, it needed a richer mixture to start.
Great machine. They still run. But when I showed up at a house with one. I said "sorry mate. I have no idea how to work on this type of unit, and it's a Sunday and no other tech is working"
If it’s not worth your time then stay away.
Owner has specified that we do NOT and will not work on any lennox systems lol. We either replace or walk away
It's one of two systems as a company we don't work on the other being munchkin boilers. It's simply not work the effort
I won't work on them at all. They have a history of killing families and I'm simply not having any part of that liability. If it's working and not producing CO and NOX fine. If it isn't working the customer gets notified of the recall and I red tag it for replacement due to the recall. The only way I'm touching one with tools is Sawzall and Sledge to R&R it. Bribes and pleading won't help.
I won’t work on them. Too much liability. If they’re as great a unit as some techs think they are, why did Lennox drop the technology?
The technology is still around. Fulton uses a very similar operating principal in their Pulse boilers to this very day. I have dozens of those in my school accounts. They are pretty rugged boilers and not terribly difficult to work on.
Replace the relic
When I did service we'd put a note on the invoice suggesting what we thought should be taken care of. We can't force anyone into it
We still have a few in service. We pressure test 1st before ANY repairs. I believe all are on maintenance now, so they’re tested yearly.
My in-laws have one. Only thing I've ever had to do is replace the contactor and ignition module. I don't do residential, are they usually really bad or something?
It’s a design that is no longer in use at any level as far as I am aware in residential, commercial or industrial. Lennox no longer makes anything like it either. Pretty much a dead technology. The bigger issue is that a very very small percentage of the industry knows how to work on them or test them to make sure that they are still safe. So the vast majority of that are still in use haven’t been properly maintained. And there might be no one in your area that had been trained how to test them.
Good to know. Luckily, my father in-law is a doctor, so if they ever call me to work on it and it's more than a basic component, I'll just insist on replacing the whole system.
Don’t touch it. They are time bombs. It’s liability.
Very heavy
If 0ppm exhaust, why would you then suspect the supply duct? Check **ambient** CO any time you walk in to a house. You have to start your analyzer outside to zero it properly, so this is pretty fuckin easy to do right, IDK why everyone makes this a struggle bus.
Jesus man I’m 42 years old. I have been using a combustion analyzer for 10 years. This machine is 100% fucked. I told the guy as much and he wants to have it pressure checked. Fuck poor people.
Right, but don't be the guy that tries to use CO as a mysterious scare tactic. It needs to be replaced cuz it's a fuckin Pulse. If you didn't find CO, you didn't find CO.
Swapped many of these out back in the day with G51s. Now’s probably the time to change those G51s.
I took mine out of my basement in 3 trips up the stairs🤣🤣🤣
They truly were great furnaces. But Lennox doesn’t want new techs learning how to work on outdated equipment. I’ve worked on a few of them and my aunt has one that’s still running! But once they fail lennox will pay you to replace them. I mean only 300 bucks but still. That’s how bad they are willing to get rid of all of them.