lennox pulse

[x-files]

When I was in colorado from 2000 to 2002 in the denver area, I remember working on these lennox gas fired funaces I believe was called the pulse. Everyone dis-liked these units. they fired with a spark plug like from a car, had a flapper on the intake that often needed changed, and the units when running were very noisy! Just curious if anyone has worked on these and your opinion. Thank God I only had to work on a few!

[mark beiser]

I have worked on tons of them. I always liked them, and if they were installed with some thought to vibration isolation, are not very loud, unless the air or gas intake diaphragms start leaking.
The air intake diaphragm is suposed to be changed every 4 years, if it doesn't get changed, causing the furnace to run rough and noisy, don't blame Lennox. :p

The early G14 Pulse furnaces were a little loud, but if the update kit that changes the gas orifice size and the regulator on the gas valve was installed, it cut the noise level basicly in half.
The G21 furnaces were not loud at all if there is even minimal vibration isolation.

Really though, if you take a furnace that has hundreds of small explosions going off in it every minute, and set it on a metal box connected to a metal return, and screw a metal plenum to it and screw that to a metal supply trunk, WTF do you expect, lol.
Iso pads and flexible connectors are a must with a Pulse furnace...

As for reliability, other than an issue with a relativly small % of G14 furnaces, the Pulse furnace is hands down the most trouble free condensing furnace.

In the 8 years since they stopped making Pulse furnaces, no other furnace has been produced that matches the efficiency of the G21. I may be wrong, but I don't think it was until last year that another furnace broke 95%.

Oh, and just an FYI, the spark plug doesn't work like it does in a car. Once the flame is established, the spark and the purge blower shut off. The proccess is entirely self sustaining.

[Milk man]

Lack of field support killed the Pulse.

It's just like everything else, once one learns the common failures they are easy to work on.

[heatpumpguru]

Failed heat exchangers and TV killed the PULSE,the story on 20/20 or one of those shows about how it was a KILLER furnace with the people who lost love ones crying how the carbon monoxide killed their family.

[lowtemp]

I remember one of our techs telling us about a Pulse furnace he had installed .Him and another guy had just spent 3 days installing a complete heating system including duct work.All this done in a 3 foot crawlspace. When they finally fired it up and it made its normal patent sound ,the customer said this " What the f*ck is that noise! The tech says" Well thats your new furnace (with a smurk).Well , the customer got on the phone to the salesman and ripped him a new A-hole. I couldnt stop laughing.I guess the salesman forgot to mention the sound it would make.

[t527ed]

Originally posted by mark beiser
I have worked on tons of them. I always liked them, and if they were installed with some thought to vibration isolation, are not very loud, unless the air or gas intake diaphragms start leaking.
The air intake diaphragm is suposed to be changed every 4 years, if it doesn't get changed, causing the furnace to run rough and noisy, don't blame Lennox. :p

The early G14 Pulse furnaces were a little loud, but if the update kit that changes the gas orifice size and the regulator on the gas valve was installed, it cut the noise level basicly in half.
The G21 furnaces were not loud at all if there is even minimal vibration isolation.

Really though, if you take a furnace that has hundreds of small explosions going off in it every minute, and set it on a metal box connected to a metal return, and screw a metal plenum to it and screw that to a metal supply trunk, WTF do you expect, lol.
Iso pads and flexible connectors are a must with a Pulse furnace...

As for reliability, other than an issue with a relativly small % of G14 furnaces, the Pulse furnace is hands down the most trouble free condensing furnace.

In the 8 years since they stopped making Pulse furnaces, no other furnace has been produced that matches the efficiency of the G21. I may be wrong, but I don't think it was until last year that another furnace broke 95%.

Oh, and just an FYI, the spark plug doesn't work like it does in a car. Once the flame is established, the spark and the purge blower shut off. The proccess is entirely self sustaining.

what he said.

[t527ed]

Originally posted by Milk man
Lack of field support killed the Pulse.

It's just like everything else, once one learns the common failures they are easy to work on.


cost of production killed the pulse.

also the weight of that monster. i used to hate dragging those things down steps into basements. once the G26 furnaces came out they were lighter, quieter and much CHEAPER. we pretty much stopped selling the pulse a couple years before they stopped making them.

looking back at when they came out in 1981 they were MANY years ahead of their time as far as efficiency went.

as others have said, once you understood them they were one of the easiest high efficiency furnaces around to work on. i am still getting alot of work on them even on ones we did not install, have a lot of companies and the local utility referring to us.

[Senior Tech]

Just a thought....could it be possible that technicians killed the production of the pulse? Based on their inability or more so their refusal to learn everything they could about it? I only ask this based on my personal observations and comments on here...gimme some honest responses. It just seems like there are a few models of furnaces here that get slammed from time to time and they tend to be the ones on the cutting edge of technology...

[mark beiser]

Originally posted by heatpumpguru
Failed heat exchangers and TV killed the PULSE,the story on 20/20 or one of those shows about how it was a KILLER furnace with the people who lost love ones crying how the carbon monoxide killed their family.

What actually killed the Pulse furnace was the G26 and the prevelence of other 90%+ efficient furnaces, lol.

Kinda tough to sell a 96% efficient Pulse furnace when Lennox, and everyone else, has another product that is 93% efficient for $1000 less.

As for the deaths in the 20/20 story, it is my understanding that the CO leak that caused the deaths was found to be from a leak in incorrectly glued joints in the PVC vent system and NOT from leaks in the secondary HX connections to the primary.


20/20 has a history of manipulating stories, and even outright fabricating product failures to make a story of it though.
Like thier blatant lie and extensive modification of a car to "prove" the unintended accelleration "problem" with mid 80's Audis.

[mark beiser]

Originally posted by t527ed
once you understood them they were one of the easiest high efficiency furnaces around to work on.

No doubt about that. If you really know Pulse furnaces well, you can diagnose most problems with them by taking the front access cover off, turning it on, and listening for 60 seconds or less, lol.

I had a customer get mad at me once. I diagnosed his G21 as having a bad control board less than a minute after turning the thermostat on and without pulling a single tool out of my bag.
The furnace ignited, but the purge blower didn't turn off, so it flamed out after a few seconds.
He didn't believe my diagnosis and got in my face a little about trying to rip him off.
I kept a control board for them on my truck in those days, so I told him I would put the new board on while he watched to see if I did anything else, and if it didn't work he could have the new board for free and that I would fix the actual problem at no charge.
30 minutes later he cut me a check for the new control board and gave me a $20 bill for putting up with him. :D

[t527ed]

still keep that board on my truck. might have to start carrying purge blowers to, used 3 in the last month. had to wait for them to come from iowa to. seems like the local branch ain't stockin squat in parts anymore.

[mark beiser]

Hey t527ed, you need any air intake diaphragms for 60 and 80k G14s, just the replacement diaphragm material?
Figuring replacement every 4 years, I have a 36 year supply of them for my one Pulse furnace customer!

[HeyBob]

Bryant Gumble killed the Pulse when he did that news story of how they were so dangerous and killed people. Every Lennox dealer in the land knew it as we watched that show.

[markwolf]

I think they may be the best furnace ever made.Anyone that thinks they were noisy has not seen one properly installed & or serviced.I guarranty that any pulse I ever put in sounded no louder than a purring houshold cat.Beyond installation issues there were several "tricks" one could do to quiet them down.After you were properly trained on how to service them they might be the easiest furnace to work on too.These units were EXTREEMLY dependable if taken care of just like any piece of equipment should be.I think the biggest problem with them is guys to stubborn or unwilling to learn how to work on them!Just a bunch of whining sissy's in my book!!

[markj]

Originally posted by Senior Tech
Just a thought....could it be possible that technicians killed the production of the pulse? Based on their inability or more so their refusal to learn everything they could about it? I only ask this based on my personal observations and comments on here...gimme some honest responses. It just seems like there are a few models of furnaces here that get slammed from time to time and they tend to be the ones on the cutting edge of technology...

I would agree with this 100%. I think part of the problem was the tech could not see what was happening, as a result they were forced to use troubleshooting skills that were not that developed. It also operated in a completly differant manner. Most techs in my area were not willing to take the time to learn. Lennox offered a 1 day class in Columbus, OH along with periodic evening sessions and updates. Poorly attended by dealers. Evening sessions would cover an area with a radius of 40 miles. Maybe 15-20 techs from 5-10 shops. Same guys all the time getting updates and learning.
Then you have the problem with techs and installers badmouthing a product that they do not understand and find difficult to install.
I worked on many. Small parts inventory on truck and you could fix just about any problem.
It is a great furnace when properly installed and maintained.
I would buy one today.

[t527ed]

Originally posted by mark beiser
Hey t527ed, you need any air intake diaphragms for 60 and 80k G14s, just the replacement diaphragm material?
Figuring replacement every 4 years, I have a 36 year supply of them for my one Pulse furnace customer!


sure, e-mail in profile let me know what you need.

[microamp]

I would have to agree that the Pulse was one of the best furnaces aver built. I went to work for a Lennox dealer in August of 83 and installed a ton of these furnaces. The installers that I worked with all believed in the Pulse and we took alot of pride in our installs and how quiet we could make them. As for any service problems, there were some over the years but none that really caused us any serious doubts in the furnace. We took in all the service workshops that Lennox put on to stay on top of any service issues that might come up. I know there are a few of the Pulses out there that probably have never been touched other than to have there heat exchangers checked, not that I condone this but it is a testiment to there durability. Then there was the CompleteHeat........

Dan

[hvaclover]

Blew an L2 and L3 disc taking a Pulse down stairs.
Atta' boy Dave!

[t527ed]

Originally posted by hvaclover
Blew an L2 and L3 disc taking a Pulse down stairs.
Atta' boy Dave!


not a furnace for the weak minded or backed. they were heavy suckers and getting them into place had to be done carefully.

[jetstream]

Hurt my back replacing a heat exchanger on one. That really soured me on the Pulse for a long time.

I thought the igniter and sensor could've been a heck of a lot more accessible!

You have to pull out the plastic holder for the motor wire to remove the blower, a pain.

Also a pain pulling the comb air cover off, hate those bolts.

And I never liked the sound, even when they're quiet it's an annoying sound.

But now that there are fewer around, I find I miss them to work on. An interesting furnace.

[wisc]

Built like a tank. Bullet proof too. Several times over the years, a homeowner would bring a Pulse up from downstate, install it and not realize he had to convert the thing to LP gas. I would get called in a year later when it started acting up. I would convert it, flush out the heat exchanger and it would start up just fine. Home owner would remark how much quieter it was. LOL

Try running any other furnace on LP without converting it and it will be junk

[oil boiler man]

The Pulse furnace, in my opinion, was one of the better furnaces Lennox came out with! unlike their completeheat!

[zipscrew]

took out another pulse today, they are the heaviest damn things.

[Milk man]

What is a compleate heat? I've never seen one.

[swagging tool]

The complete heat is a water filled gas fired modulating nightmare!!!!! lol. I still remember the first 40 I put in and then took out. But man oh man those things made some hot water more hot water than anyone would ever need.

[mark beiser]

Originally posted by Milk man
What is a compleate heat? I've never seen one.

Imagin a modulating demand water heater built into a storage tank, used for domestic hot water and for heating coils in one or more air handlers.
Only the company making it has no previous experiance with making either demand water heaters, hot water storage tanks, or hydronic heating...

Frightening isn't it? :D

[Edited by mark beiser on 11-01-2006 at 12:40 AM]

[swagging tool]

hey mark sounds like you went through the complete heat nightmare too lol. I put a couole of those things in a house once and man oh man what a job they wanted infloor heat in the carport radiant heat in the basements forced air heat in the main floor and they had big hot tubs and jacuzzis that did'nmt have heaters they had stainless steel heat exchangers that robbed heat from the complete heat. Then one day we got a letter from lennox telling us that we needed to shut it down untill they sent a replacement yeah right but we did and did the replacement in a couple of days but those people that had them were afraid of them for the rest of the time i was working at that lennox dealer and their whole house all 1.7 million dollars worth was based on complete heat comfort and hot water service. Man I am glad I did'nt own that lennox dealership and sell those folks those units whew!!!!!

[danielzig]

I just bought this current house back in July. I have a G14Q3-80. I am wondering what kind of spare parts if any I should have on hand for this furnace. I am looking for a place on-line that sells air falpper diaphragms. Also, the blower comes on immediately after the purge motor stops running, just as the unit is starting its intial fire. It doesnt go off for what seems like 5 mins afterwards. I tried adjusting the existing fan-limit control, but I did not work. Any help on that issue would be greatly appreciated.

[mark beiser]

The fan control in that furnace is timed on, so there is no adjustment for when the fan turns on.

There may even be a sticker on the furnace already that shows the date of the last pressure test.

If you don't know when it was tested last, or it has been 4 or more years, have someone with the correct tools and experience come out and pressure test the heat exchanger.

The air intake diaphragm also needs to be replaced every 4 years.

There was also an update kit for the G14 furnaces that changes the gas pressure regulator part of the gas valve, and gas orifice size. If this has not been done, I would recommend you have it done.
The surest way to tell if the update kit has been installed is to look at the gas valve.
On the side of the valve that has the on/off knob and wire connections there is a rectangular piece that is held on by 2 screws. It has a slotted cap on it and round plug that is facing down. There should be a number printed on it that indicates the gas pressure.
If a G14Q3-80 has the updated regulator, the number will be "2.2".
If it has a different number, you should get the update kit installed. The kit also has new air and gas intake diaphragms. This would also be a good time to replace the flame sensor and spark plug.

If you have the service history available and all this has been done, just continue with the 4 year interval on the pressure test and air intake diaphragm, and normal yearly service checks.

[tn a/c man]

One of the best furnaces ever made in my book.

[folster]

if you have a pulse furnace contact your lennox dealer you should be able to recoup some sort of warranty for the heat exchager the pulse furnace is very dangerous and shold be condemed the heat exchanger it is very dangerous to be still be operating

[danielzig]

The heat exchanger has already been replaced and the update kit was already installed. I basically just need to know if the air diaphragm's are available online anywhere. As far as the blower goes, I can trace the power lead of the blower, I do not know whether it is low speed or not right now, back to L1 back through the fan-limit switch. How would this be turned on by a time delay as well? If it is turned on by a time delay, what use is the fan switch?

[MikeJ]

Originally posted by folster
if you have a pulse furnace contact your lennox dealer you should be able to recoup some sort of warranty for the heat exchager the pulse furnace is very dangerous and shold be condemed the heat exchanger it is very dangerous to be still be operating

You are full of misinformation and should not be posting about something you don't know about. Pulse furnaces had problems, problems were fixed in later (by 1991) models but like all furnaces, they should be inspected by a qualified tech. With the Pulse, a pressure check will monitor integrity of the secondary heat exchanger.

[t527ed]

Originally posted by danielzig
The heat exchanger has already been replaced and the update kit was already installed. I basically just need to know if the air diaphragm's are available online anywhere. As far as the blower goes, I can trace the power lead of the blower, I do not know whether it is low speed or not right now, back to L1 back through the fan-limit switch. How would this be turned on by a time delay as well? If it is turned on by a time delay, what use is the fan switch?


fan limit has`a 24 volt heater in it that actually brings fan on sooner. g21 pulse furnaces are controled by time only.

[mark beiser]

Originally posted by danielzig
As far as the blower goes, I can trace the power lead of the blower, I do not know whether it is low speed or not right now, back to L1 back through the fan-limit switch. How would this be turned on by a time delay as well? If it is turned on by a time delay, what use is the fan switch?

The system uses a different speed for heating than it does for fan on/cooling.
The time delay for the blower in the heat mode is part of the fan/limit control.
If you turn the fan "on" at the thermostat, the fan relay closes in the furnace and runs the blower in the cooling speed.

[lennoxman]

It was way ahead of it's time. Give a home owner something he needs to have serviced regularly and it won't happen. I personally think it was a great furnace. Most techs I know are scared to death of them. I think it is because too many techs don't care to learn.

[swagging tool]

I left the lennox dealer I was working for before the heatexchanger scare came about but I do still have a couple of pulse furnaces working in my famlies homes all were g 21 models. Did the G21 fall under the heat exchanger problems as well as the 14 and 16 or were most of the problems fixed by the time the G21 came out??? Thanks for any info.

[tinknocker service tech]

Originally posted by folster
if you have a pulse furnace contact your lennox dealer you should be able to recoup some sort of warranty for the heat exchager the pulse furnace is very dangerous and shold be condemed the heat exchanger it is very dangerous to be still be operating

I think you have been grosely misinformed.

The pulse hx had a 1 percent failur rate between the us and canada. Lennox had an inspection program going on all pulse furnaces built before 1990 or under the model#g-14
there were certain welding meterail use in one plant that would break down from outside pulatants on the secondary heat exchanger. The failure rate on a lot of other furnaces is a hole lot higher.

The pulse was and imo still is way ahead of its time at 97 percent eff. It is also the easest furnace to repair imo and is one of the most reliable ever made

Seems the biggest problem the pules ever had was lack of knowlege and misinformed people

It is a shame it had to give way to cost. The cost to make just one hx lennox could make five complete furnaces.