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Pulse Furnace
Question
I’ve had a Lennox Pulse furnace for about four years, and I CANNOT recommend
that anyone buy one. In the last four heating seasons we have not had one
month of satisfactory service from this furnace.
The main problem we’ve had is that the furnace keeps shutting off midway
through the heating cycle. Of course it would restart, but then a little
while later it would shut off again. Usually when the service people came
out the problem woud be “fixed” for a couple of days. Usually the problem
is diagnosed as a part that’s gone bad, very uncommon this early in these
“high quality” furnaces, yet we have had the following items replaced so far
(some under warranty, some at my expense): thermostat relay, gas valve, and
the controller board. Plus the mounts for the heat exchanger seem to have
failed, but the service person suggested waiting for spring to fix that.
Also, we’ve had a gas pressure regulator installed, the gas pressure
regulator replaced after a year. Oh, yeah, and the air cleaner power supply
had to be replaced this spring.
That gas valve was replaced last Thursday. Friday, Saturday, and Sunday
morning, as the house was recovering from nighttime setback, the furnace
would come on for a while and then start up with this on/off crap. You can
bet I was on the phone first thing Monday morning. The service people
couldn’t offer any explanation, so we’re waiting for the next cold spell to
have them see for themselves.
These service people really don’t seem like bozos, and they seem like they
know what they’re doing other than that they can’t find the damned gremlin
in my system. I don’t know what to do.
More advice: If you DO decide to go with a pulse furnace be aware that the
“gentle hearbeat” quickly becomes an invasive hum that permeates your home.
It grates on your nerves. And, since there is vibration associated with the
technology, the furnace WILL work itself out of balance to the point that
the hum becomes a conversation-stopping roar. The fix is to have the
service person remove the fan cage to get deep into the bowels, and
rebalance the combustion chamber. Even when properly balanced and tuned the
sound put out by the Lennox Pulse furnace can cause bottles in our fridge
and the coils in our toaster to resonate.
Any suggestions welcome.
Answers
I have had two Lennox pulse furnaces for the last two years. I have
had no problem with them. In your case, I wonder if it is the
furnace or it is the service “technicians”. As most of us have
experienced some time or the other that all Hightech appliances
are hard to service, for obvious reasons. Service people are
no where near trained to the level of advance technology that
hightech devices require. Diagnosing a problem in todays’s cars,
todays’s electronic dishwashers, etc, is to start replacing
parts left and right until the problem solves itself! A friend of
mine’s car showed overheated indicator – the dealer replaced first
the coolant pump, next the battery, next the whole control module,
and fianlly the heat sensor!
Lennox definitely deserves the blame for (a) not training the service
people adequately and (2) making the problem hard to diagnose.
Let me take a stab at some possible causes for your problem. Most
furnaces will shutoff if either (a) heat exchanger gets too hot or
(b) the blower motor gets too hot. Either case should not happen
under normal circustances. Three abnormal situations are likely.
(1) The thermostat is set too high when the outside is very cold and
the house poorly insulated – making the furnace run constantly.
(2) The home owner has closed several vents, thus causing a load on
the blower and reducing effective heat transfer. When (1) and (2)
are combined the shutoff becomes much more likely. (3) The heat
sensor on the motor or the heat exchanger is malfunctioning.
Associated Pulse Furnace Question: why does lenox pulse 21 furnace not blow out of the registers very good?
my lenox pulse 21 furnace seems like it is not putting out enough heat at the registers around the house it seems like the air flow is restricted
- Answer: This Question has not been answered yet! Send us Your best pulse furnace Answer!
Associated Pulse Furnace Question:Why can’t I find parts for a Lennox G21 Series Pulse gas furnace?
If you go to the Lennox.com/owners/manuals website, the model is not even listed! My problem is this: There is a component inside the unit made by Johnson Controls. Depending on where you look, (and believe me, I’ve loked PLENTY) it’s variously called an “ignition control(ler)”, burner control, flame controller, etc. It’s m/n is G891TCA-8102, it’s p/n is 34K8301, and I have founf it listed by repair companies as a 1GM60JOOA and/or 60J00. Mine works intermittantly, and when it doesn’t, if you tap it lightly w/ a screwdriver you can hear a relay on the board pull in and the purgr/ignition cycle begin. Does anyone else experience this problem? Short of buying a new component, which is $330, is there any way to correct the problem? Is there anything else I should look for? Does anyone else have a better price? Would you advise I install it myself, or have a pro do it?
- Answer:The furnace is obsolete,but the part has been upgraded. There is no other way to repair the board….you will have to buy a new board & have a licensed A/C & heating tech install it for you….call around to each company for a price estimate first…….
Associated Pulse Furnace Question:i have a lennox pulse furnace and would like to make a muffler for the exsaust, anyone know how?
i have a lennox pulse furnace and it works great, but i’m getting tired of the exsaust noise, i see they make a muffler for them but they cost dam near 200 buck each, so i thought i bet i could make one
- Answer:Not a good idea. Couple of reasons. You may end up with too much back pressure and the furnace wont vent properly. If it runs at all, it will be running too hot, which will not be good for the furnace. You could also end up with exhaust gases “backing up” into your house. You don’t want to be breathing carbon monoxide or any of the other gases in there. What you are proposing to do is actually “altering the appliance” with an uncertified component. If there was ever a fire and you had people hurt or property damaged, insurance companies would not pay and you would be liable. Suddenly that $200 bucks doesn’t sound like a lot does it? It’s worth the piece of mind knowing the muffler was made specifically for that furnace and it will be perfectly safe operating with it.
Associated Pulse Furnace Question:Lennox Pulse Furnace ignites then dies a few seconds later.?
My 1989 lennox pulse g14 furnace will start the purge fan then start burner and then the burner will die a few seconds later, then 30 seconds later it will start up and run fine. It is every other time the furnace is started that the burner goes out after a few seconds like clockwork. I have cleaned and checked the spark plug and the flame sensor. Should I replace the flame sensor or ? Good educated guesses. I did take the purge air box cover off and I vacuumed about 10 dead Bumblebees from around the purge fan so maybe it is a clogged inlet pipe. I will take the air box cover off again tomorrow and let my shop vac suck on the inlet pipe inside the unit while I blow my leaf blower in the inlet from the outside and I’ll see what I get in the vac.(No pun intended). I will also take the air flapper off to clean it up just in case it’s clogged. That’s very true about the Heat exchanger I will buy a carbon monoxide detector or two but replacing the Furnace is not an option right now. The last time the heat exchanger was pressure tested for leaks was 9/2005. I’ll keep you posted. Inspected and cleaned the flame sensor, spark plug, Air flapper, purge fan, vacuumed out air intake box and inlet piping and blew compressed air through condensate drain but the furnace is still shutting down after a few seconds of ignition on first start up but running fine otherwise. I did notice today that when the furnace has not been ran for hours it will stay running on first attempt but the problem persists every other attempt after the successful cold start. Pressure switch maybe or??
- Answer: This Question has not been answered yet! Send us Your best pulse furnace Answer!
Associated Pulse Furnace Question:Furnace Wont light (lennox pulse gc-1)?
I have a lennox pulse furnace Model gc-1. When i turn the unit on and call for heat the furnace starts clicking for around 6 seconds then stops for a short time. then tries to light again and stops. after about 5 times a red service light comes on and stays on. ( no blinking) the light is on the Ignition control board (black box where the spark plug goes in?) If i cycle the power off and on repeatedly for a while sometimes it will light and the blower will kick on and it will heat up. but that’s only if im lucky. Any ideas what it may be? i cant afford a tech person
- Answer:Honestly, even if you can’t afford it you are gonna have to call a Lennox tech on this one. Due to some MAJOR problems and lawsuits that Lennox had regarding these Pulse furnaces several years ago most HVAC companies won’t touch them, leaving only a Lennox dealer who will work on them. Leave it alone and call a Lennox dealer, the furnace is not user serviceable.
Associated Pulse Furnace Question:Lennox Pulse furnace kicking on and off?
I have a 20 year old Lennox Pulse furnace. It switches on normally when the temperature goes down, but it switches off after running for a minute or so, even though the temperature hasn’t gone up. Then it switches on again in a minute or so. It keeps cycling like that. Sometimes, it runs only for a few seconds. What could be the problem? Just wanted to add this to my question: The furnace is still heating the house, though slowly due to the short cycles (so, pilot must be lit). I can see water coming out of the drain pipe off the trap. Would it still be clogged? I have to cut the PVC to clean out the trap. Will try that this evening. Also, I will try replacing the thermostat. Also, if it helps, I hear a clicking sound when the unit prematurely shuts down at the end of a cycle.
- Answer:sounds like you may have a bad spark transformer, or sparker.
Associated Pulse Furnace Question:I have a Lennox Pulse G21 Furnace installed April 21,1994. Is there a heat exchanger corrosion problem?
I understand that the corrosion problem occurred on Lennox Pulse Furnaces that predate 1990, is this this correct? Therefore our 1994 model should be fine?
- Answer:You should have your HVAC unit checked at least once a year, twice if you have AC. The technician should be NATE certified. A rusted Heat Exchanger can release Carbon Monoxide into your house which can and does kill. A preventative maintenance cost is a small price to pay for your safety
Associated Pulse Furnace Question:What is the Lennox Pulse 21 heat exchanger recall?
I have a Lennox Pulse 21 furnace installed around 1996 or so. A heating & cooling company came out today to discuss installing A/C on the unit. After looking at the heat exchanger, he told me there was green corrosion and subject to Lennox’s recall. He told me that Lennox will give me a brand new furnace for free, all I have to do is pay for installation. My concern is that he has a great incentive to replace my furnace because he will charge the labor for replacement, perhaps enough of an incentive to suggest replacing a furnace that doesn’t need replacement (considering the fact that this is not why I called him out in the first place). Has anyone else replaced their Lennox Pulse 21 via this heat exchanger recall program? If so, do you have any suggestions?
- Answer:Call 1-800 4 LENNOX with your model #, not necessarily your serial number, ask them if this is on the up and up. Also, you could call a Lennox dealer and ask them, you don’t have to tell them you are trying to catch another contractor in a lie, a lot people do not want to get into that. Just ask about recall on the Heat Ex.
Associated Pulse Furnace Question:lennox pulse 21 100,000 BTU conversion propane to natural gas?
We have two lenno pulse 21 furnaces (1989) placed into use in 1995, which we need to convert from propane to natural gas. Estimates for conversion have been 500 dollars per unit…Is this reasonable?
- Answer:No it is not resonable but given the age of the furnaces I am surprised the con. kits are still available. I would be more concerned about the high probability that the heat exchangers may well be broken. Your pulse furnaces are from a time when it was not good to own a pulse. Do a search on your furnaces, you will read some nightmare stories on these units. The Lennox web page used to come up completley red with warnings. Law suits, carbon monoxide are just a couple of the subjects associated with the older pulse furnace.
Associated Pulse Furnace Question:Lennox Pulse 21 Shuts Down?
I have a Lennox Pulse furnace. M/N G21Q4/5-100-3. The unit starts but does not continue running. The blower does not kick on when it calls for heat. Sometimes, however, everything works fine. I have replaced the controller and the gas flapper. I also have drained the water in the stand pipe. I now have determined if I leave the blower in the “on” position rather than the “auto” position, everything works fine. What is the solution to my problem?
- Answer:It sounds like it could be the fan timer control. That is the control that turns the fan on and off in the heating mode on that furnace. You may also want to check out the run capacitor and fan motor. For a step by step troubleshooting guide, check out my source.
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