Lennox Model G24M3-75A-4

When selecting heat, fan comes on with heat demand and ignitors start immediately clicking. This shouldn't happen. Ignitors should wait 45 seconds before clicking. It'll keep repeating until locked out.

When ignitors start clicking when blower starting, I'll move temp down and after turning system on/off moving temp up/down several times, make that numerous times over a two hour period, the system will finally work. Meaning, fan comes on and after a 45 second delay the ignitors click and the system works.

Furnace will work normally until termostat manually set to cool. Then problem starts over again when the need to return thermostat to heat.

Other symptoms a
It'll display solid diagnostic lights indicating control board failure after a few attempts, but not at first;
set fan from auto to ON and fan doesn't work, just makes a soft clicking noise, control board will indicate board failure;
Air Conditioner works everytime when placed to cool.

What/which parts do I change first?

What is causing ignitors to click at same time as blower starting?

Why doesn't my fan work when set to ON?

Please help.

On Wed, 15 Dec 2004 04:40:53 +0000, tripntx
wrote:


Lennox Model G24M3-75A-4

When selecting heat, fan comes on with heat demand and ignitors start
immediately clicking. This shouldn't happen. Ignitors should wait 45
seconds before clicking. It'll keep repeating until locked out.

When ignitors start clicking when blower starting, I'll move temp down
and after turning system on/off moving temp up/down several times, make
that numerous times over a two hour period, the system will finally
work. Meaning, fan comes on and after a 45 second delay the ignitors
click and the system works.

Furnace will work normally until termostat manually set to cool. Then
problem starts over again when the need to return thermostat to heat.

Other symptoms a
It'll display solid diagnostic lights indicating control board failure
after a few attempts, but not at first;
set fan from auto to ON and fan doesn't work, just makes a soft
clicking noise, control board will indicate board failure;
Air Conditioner works everytime when placed to cool.

What/which parts do I change first?

What is causing ignitors to click at same time as blower starting?

Why doesn't my fan work when set to ON?

Please help.

You obviously dont have a clue how the system works. Thats ok. You
shouldnt. Thats why there are repair techs take care of it. No one can
diagnose it over the net. Get it looked at by a qualified technician.
You'll most likely save a lot of money in the long run.
OR, you can just change parts until you get it right.
Note: Lennox parts are very costly compared to others and they are
almost impossible for the homeowner to purchase.
Bubba

You're right. I don't have a clue as to the role individual components play. I do know, when my heat is working properly:
1. evacuation blower starts for 45 seconds
2. after 45 seconds, ignitors click once or twice and burners light
3. air handler blower comes on to distribute heated air

Currently, evacuation blower and ignitors start at time, burner doesn't light. I do not mind replaceing the most likely components, because local technicians around here will do so as there means of troubleshooting. I'm just trying to cut out paying someone else labor to sub in components until it works.

On Wed, 15 Dec 2004 15:19:41 +0000, tripntx
wrote:


You're right. I don't have a clue as to the role individual components
play. I do know, when my heat is working properly:
1. evacuation blower starts for 45 seconds
2. after 45 seconds, ignitors click once or twice and burners light
3. air handler blower comes on to distribute heated air

Currently, evacuation blower and ignitors start at time, burner doesn't
light. I do not mind replaceing the most likely components, because
local technicians around here will do so as there means of
troubleshooting. I'm just trying to cut out paying someone else labor
to sub in components until it works.

Evacuation blower? That would be an inducer motor assembly
Igniters click? Spark ignition may click. An igniter (glow coil) just
glows. Pilots burn.
Air handler blower? So what exactly do you have? An air handler or a
gas furnace? I havent seen an evacuation blower in an air handler.
Like I said, you most likely wont be ablte to get Lennox parts. They
have their own tight little network. If you do, you will pay dearly
for them.
Tell me this and Im being serious as a heart attack.
Why on this freakin earth would you pay a technician to replace parts
(or his labor) until he guesses the right one?
Now if he wants to replace them all one at a time until he gets the
correct one and then charges you for that part only plus a diagnostic
fee of some type, then that would be fair. Its a stupid way of fixing
a furnace and it involves no skill at that point but HEY, its your
dollar.
All the more reason to call a company that charges "Flate Rate
Pricing". You get quoted a service call/diagnostic fee before they
even show up. Then he can diagnosis and replace parts until his hearts
content. You are only going to pay for what it takes to fix it AND you
get the quote BEFORE it gets fixed. If he quotes you a repair too high
that you cant live with, you pay the diagnostic and show him the door.
How simple can that be?
.....and again, from your description and terminology, you really
should leave your furnace alone and let someone look at it that knows
what they are doing.
Bubba

I was broiled pretty good a few years ago over in alt.hvac.... and in
that time, managed to find two HVAC techs in that forum I respected.
One was Bubba, the other was Paul.

Tripntx - as an owner of a Lennox furnace, I'm BEGGING you to take
Bubba's advice. Mine is a G27M, and has gone out EVERY fall since I
bought it 4 or 5 years ago.

EVERY part has been replaced... and I MEAN EVERY PART, each visit done
by a Lennox tech. I'm not making this up....... the ONLY original part
left on the furnace is the frame, and I expect it will probably fail
too.

Out of the 12 or so techs that have visited my house - I'd say 2 were
competent. The rest were parts changers.

My point is that Lennox makes CRAP, and the companies that service them
can't even really keep up with the crap level.

Call a service tech, and WATCH THEM. Don't be a dick, but be aware of
what they are doing. You'll know pretty quickly if you got a good tech
or not.

Even if you get a "parts changer".... so what - just keep track of what
they do, and you'll know what you should be charged for.

By swapping parts yourself, you are simply setting yourself up to make
the situation much worse. I can virtually GUARANTEE that you will swap
the wrong part, and as Lennox makes such CRAP it's likely you will
break something else in the process. This isn't a slam against you -
it's just that not even Lennox repair parts are fully swappable..... on
the third installation of a new control board, they finally put in some
sort of "upgraded" model. This WAS NOT a swap out situation - wires
were cut from connectors and routed to other boards, new connectors
were installed on other wires... etc.

Take Bubbas' advice man - DO NOT attempt to repair something that can
kill you and your family in your sleep.

On 15 Dec 2004 13:04:29 -0800, "Matt" wrote:

I was broiled pretty good a few years ago over in alt.hvac.... and in
that time, managed to find two HVAC techs in that forum I respected.
One was Bubba, the other was Paul.

Tripntx - as an owner of a Lennox furnace, I'm BEGGING you to take
Bubba's advice. Mine is a G27M, and has gone out EVERY fall since I
bought it 4 or 5 years ago.

EVERY part has been replaced... and I MEAN EVERY PART, each visit done
by a Lennox tech. I'm not making this up....... the ONLY original part
left on the furnace is the frame, and I expect it will probably fail
too.

Out of the 12 or so techs that have visited my house - I'd say 2 were
competent. The rest were parts changers.

My point is that Lennox makes CRAP, and the companies that service them
can't even really keep up with the crap level.

Call a service tech, and WATCH THEM. Don't be a dick, but be aware of
what they are doing. You'll know pretty quickly if you got a good tech
or not.

Even if you get a "parts changer".... so what - just keep track of what
they do, and you'll know what you should be charged for.

By swapping parts yourself, you are simply setting yourself up to make
the situation much worse. I can virtually GUARANTEE that you will swap
the wrong part, and as Lennox makes such CRAP it's likely you will
break something else in the process. This isn't a slam against you -
it's just that not even Lennox repair parts are fully swappable..... on
the third installation of a new control board, they finally put in some
sort of "upgraded" model. This WAS NOT a swap out situation - wires
were cut from connectors and routed to other boards, new connectors
were installed on other wires... etc.

Take Bubbas' advice man - DO NOT attempt to repair something that can
kill you and your family in your sleep.

Damn Matt. You cant be a real human. You seem to have a working
thinking brain. hehe. Just kiddin. Its meant to be funny. Your advice
is right on too. Lots of hvac companies and customers are afraid of
flat rate pricing but where else do you buy anything on time and
material? Do you pay for your hair cut on time and material? How about
that new car or truck? Does that menu at McDonalds tell you how much
your food bill will be before you eat it? Why would anyone want a tech
to come in and pay them on a time and material basis?
Yes I can be a grumpy old ******* when I want to be. So is Paul but I
know my **** the same as he does. Sometimes its just frustrating
watching customers ****ing away money and risking lives to save a
dollar.
By the way, all the equipment out there is crap due to increasing
competition and costs. You just have to find that Great Installer.
Bubba

I agree with bubba, but, first thing to check is your supply
voltage,common and ground. If you find that hot ( L1 ) to common is not
the same as ( L1 ) to ground that is your problem. Have had this
happen, Lennox is very ground criticle. Found that L1 to ground was 100
volts or less and that was the problem.