lennox pulse furnace

[mb20fan]

Anyone ever replace the 3/4 hp blower in the g/14q.Lennox say`s I have to buy there's it`s heavy duty and any other 3/4 hp motor will fail fast.Well the motor they sell is close to 350.00 and they don`t have one here close.It`s fricking cold out here in Ann Arbor.My normal supply house has a 3/4 hp motor and cap for under 200.00 that will fit lennox mounting bracket.

[martyinlincoln]

Pressure tested the heat exchanger yet? No sense sticking a motor in if the heat exchanger fails inspection.

[t527ed]

yes it's expensive, others will fail.
remove your pricing and pressure test the hx.

[mb20fan]

yes it's expensive, others will fail.
remove your pricing and pressure test the hx.

i got a ao smith motor it has no white wire or neutral wire.So what wire do I use for common.

[Rob_in_WV]

The wire designations should be listed on the tag on the motor body. What is the motor part number?

[JAYLUPARK]

Yellow is usually common if no white.

[Milk man]

Replacement motor will probably fail soon. I'd do OEM only.

BTW, did the furnace pass the pressure test?

[jhunter97]

Id replace the whole furnace parts becoming mor and more obsolete be much better in Long run to replace. Great rebates to replace!

Sent from my HTC Hero S using Tapatalk 2

[crmont]

Yellow is usually common if no white.

Um that's probably incorrect. I Hate to see a smoked motor.

[small change]

AO Smith has some Blower Motors that have a yellow wire as common

Also they sometimes use purple and of course white

[pacnw]

I have seen the statement "... yellow/white for common..."
But as stated, there should be a reference on the motor itself!!

[GastecD]

Agree with changing the furnace, once you have to change out a spark plug youll be wishing you had

[DOGBOY]

Agree with changing the furnace, once you have to change out a spark plug youll be wishing you had

I can change out the flame sensor and spark plug in less than 5 minutes. that is being at the furnace it has cooled down & the little panel already off. There are easy ways to do a lot of jobs you just have to think outside of the box.

dogboy

[GastecD]

Have you tried removing one that was siezed?

[jm0711]

To answer your original question....on that furnace the oem motor is the only one to use. Any other motor will fail quickly. I don't know what's so special about that motor or the design but an aftermarket motor will not last.

[DOGBOY]

Have you tried removing one that was siezed?

Can not truly answer that as I never had a problem getting them out. Back in the late 90's (98-99?) I was performing 4 -6 pulse inspections a day and installing update kits on every one. gas orifice, gas flapper, air flapper, (both were assembly's not material) spark plug and wire and last sensor. never had one I could not get out. some were harder than others but easily done in 5 minutes.

and yes you have to use the motor from lennox as any other will not make it 2 years. Probaboy not 1 year.

dogboy

[Rob_in_WV]

Um that's probably incorrect. I Hate to see a smoked motor.

I saw one that was wired up wrong and cooked the fan coil board on a carrier Air handler.

[hvac5646]

and yes you have to use the motor from lennox as any other will not make it 2 years. Probaboy not 1 year.

dogboy

You saying that the motor the OP is posting about is made specially for Lennox and no other motor can replace it ...? and no other

Care to elaborate. motor would last as long?

[chuckcrj]

You saying that the motor the OP is posting about is made specially for Lennox and no other motor can replace it ...? and no other

Care to elaborate. motor would last as long?

I've used universal motors many times and haven't had an issue. Match rpm and HP and there is no reason it shouldn't last as long as the OEM part.

[DOGBOY]

I have replaced motors on the 4/5 ton drive pulses after someone had already replaced it with a generic motor. Maybe only 5 -7 times but when I was with a larger lennox dealer other technicians saw this also.

To me this kinda goes with tranes outdoor fan motor needs to be replaced with the oem as every one that was not oem installed by the company I was with at the time would fail with in a month or two.

Just my experience. ??

dogboy

[mark beiser]

Ahh, the good old Lennox 27F01 motor, or whatever the number is these days.
Don't repeat the frustration of thousands of technicians before you, just buy the OEM motor.


I've used universal motors many times and haven't had an issue. Match rpm and HP and there is no reason it shouldn't last as long as the OEM part.

The motor in Lennox 4/5 ton drive furnaces is a 3/4 hp, 1075 rpm motor.
I'd bet you several $100 bills that any of your normal supply house 3/4 hp 1075 rpm motors, or rescue type motors, will overheat and fail in place of the motor Lennox uses.

I've even had a real motor supply/repair shop try to match one up for me and fail.
I've seen mention that either AO Smith or Fasco makes a motor that will replace the OEM motor, but I've never found one for sale in a supply house.

[mark beiser]

To me this kinda goes with tranes outdoor fan motor needs to be replaced with the oem as every one that was not oem installed by the company I was with at the time would fail with in a month or two.

If you are talking about the 1/4 hp, 825 rpm, 1.9A motor, try a US Motors or Emerson #1873.
I've been using them on AS/Trane units for years, and haven't had a single issue with one.

For the 2 speed motor in Tran's 4 and 5 ton XL1200 units, the 1/3 hp 1075 rpm Mars SOS motor works nicely.

I even found an alternative to the motor used in the XB1000 units that have the small bolt pattern, but I can't remember the GE part number.

[hvac5646]

I've used universal motors many times and haven't had an issue. Match rpm and HP and there is no reason it shouldn't last as long as the OEM part.

That's the way we all we're trained to replace motors. The bearing type must also be taken into consideration, I think, is also worth mentioning.

But I find it hard to accept there is no after market replacement for ANY oem motor, let alone Lennox.

[mb20fan]

Id replace the whole furnace parts becoming mor and more obsolete be much better in Long run to replace. Great rebates to replace!

Sent from my HTC Hero S using Tapatalk 2
That`s what I told the homeowner.The cabinet has so much rust on it.

[mb20fan]

You are right come to find out home owner put the failed motor in 6 month`s ago.It used a 40 mfd cap when it failed he put a 100 mfd cap on it at 6pm by 2 am the house was filled with smoke and smelled like a electrical fire.So when I put new motor in I kicked up that smell.I thought I was burning up new motor.That`s when homeowner told me what happened.

[billg]

Ahh, the good old Lennox 27F01 motor, or whatever the number is these days.
Don't repeat the frustration of thousands of technicians before you, just buy the OEM motor.



The motor in Lennox 4/5 ton drive furnaces is a 3/4 hp, 1075 rpm motor.
I'd bet you several $100 bills that any of your normal supply house 3/4 hp 1075 rpm motors, or rescue type motors, will overheat and fail in place of the motor Lennox uses.

I've even had a real motor supply/repair shop try to match one up for me and fail.
I've seen mention that either AO Smith or Fasco makes a motor that will replace the OEM motor, but I've never found one for sale in a supply house.

Now I have to know what is special about the motor. Did you ask the motor repair guys what it is? If I were to guess I think it has something to do with starting torque.

[pacnw]

I cannot explain why either, but I work for a Lennox dealer and they will NOT put in anything but OEM in the Pulse because it does not last.

I have been back on some that other companies have installed aftermarket motors in a sort time prior. The HO thinks the tech did not do something correct and that is why the new motor died so soon.

We just say it is wired correctly, as long as it is, and order the OEM motor and cap. Usually never have an issue unless it is a bad motor out of the box.

[chuckcrj]

Ahh, the good old Lennox 27F01 motor, or whatever the number is these days.
Don't repeat the frustration of thousands of technicians before you, just buy the OEM motor.



The motor in Lennox 4/5 ton drive furnaces is a 3/4 hp, 1075 rpm motor.
I'd bet you several $100 bills that any of your normal supply house 3/4 hp 1075 rpm motors, or rescue type motors, will overheat and fail in place of the motor Lennox uses.

I've even had a real motor supply/repair shop try to match one up for me and fail.
I've seen mention that either AO Smith or Fasco makes a motor that will replace the OEM motor, but I've never found one for sale in a supply house.

What is different about it?

[DOGBOY]

What is different about it?

you do realize we are service techs and not engineers? Right? some of us know what works and what doesn't.

dogboy

[hvac5646]

you do realize we are service techs and not engineers? Right? some of us know what works and what doesn't.

dogboy

I am sure we don't have to be engineers just because we want to know why an OEM part can not be crossed to to a competitive brand.

A motor is windings bearing a stator and a housing.
I have yet to find an OEM motor I cant cross.

I don't think an HO would appreciate a shoulder shrug in place of a reason why an OEM costs more than a generic part.

[mark beiser]

What is different about it?

The OEM motor has a thicker winding stack, higher amperage rating, and weighs significantly more than any of the commonly available 3/4 hp blower motors.
A motor shop even had me try a 1hp motor, didn't work out.

Look at the blower wheel in Lennox 4/5 ton drive furnaces from the 80's and 90's, not just the Pulse, but the 80MGF, G24, etc., it is bigger than you typically find in other furnaces.
If you look at the blower performance charts for those units, you will see that they have a significantly more powerful blower than most.

I've no doubt that there are aftermarket motors that will work, it's just a question of if anyone actually stocks them, which I've never had any luck with, even when dealing directly with a motor shop.

[billg]

The OEM motor has a thicker winding stack, higher amperage rating, and weighs significantly more than any of the commonly available 3/4 hp blower motors.
A motor shop even had me try a 1hp motor, didn't work out.

Look at the blower wheel in Lennox 4/5 ton drive furnaces from the 80's and 90's, not just the Pulse, but the 80MGF, G24, etc., it is bigger than you typically find in other furnaces.
If you look at the blower performance charts for those units, you will see that they have a significantly more powerful blower than most.

I've no doubt that there are aftermarket motors that will work, it's just a question of if anyone actually stocks them, which I've never had any luck with, even when dealing directly with a motor shop.
Thanks for telling us what you found, I like always like to know the why:)

[chuckcrj]

The OEM motor has a thicker winding stack, higher amperage rating, and weighs significantly more than any of the commonly available 3/4 hp blower motors.
A motor shop even had me try a 1hp motor, didn't work out.

Look at the blower wheel in Lennox 4/5 ton drive furnaces from the 80's and 90's, not just the Pulse, but the 80MGF, G24, etc., it is bigger than you typically find in other furnaces.
If you look at the blower performance charts for those units, you will see that they have a significantly more powerful blower than most.

I've no doubt that there are aftermarket motors that will work, it's just a question of if anyone actually stocks them, which I've never had any luck with, even when dealing directly with a motor shop.

Interesting. I have replaced a lot of Lennox motors with non OEM with no problems, but don't remember how many of them were 3/4 HP. I would guess that only about 1% of the pulse furnaces I've worked on are the 100k with the 4/5 ton blower.

[mb20fan]

The old motor is a lot heavier than aftermarket one for sure

[slctech]

The Pulse's heat exchanger runs about twice as hot as any other furnace. Thus, a larger and beefier blower wheel to move more air to meet the temp rise. Most off the shelf after-market blower motors can not handle the blower wheels in those Pulses, as earlier stated.

[mb20fan]

This house is a mess bad electrically the furnace breaker has a bunch of lighting on it.Plus a few outlets the thing is only a 15amp.This furnace will use most of that by it self and all of it on start up.not to mention it`s a lot of knob and tube still

[JUSTADDSOMEMORE]

Just replaced one 2 days ago. Part # 28F01. Pricing is about right. Use OEM the first time or you will be buying it for them next week.

[davidj001]

its been a while, but the last time i changed one it wasn't all that bad. the way it was installed under the house sucked
Agree with changing the furnace, once you have to change out a spark plug youll be wishing you had