Furnace blower rattling
Robert Hancock
annoying, rhythmic rattling sound. It only seems to happen when the furnace
is cool (like after the burner has turned off but the blower is still
running). I checked for anything rattling around in the blower housing, and
tightened down the bolts on the rubber mountings, but it didn't help. You
can make the same rattling sound if you grab the part that the motor and
blower shaft sits on and jiggle it around. Could this be the bearings on the
blower shaft that are worn out and allowing the shaft to rattle around?
Also, when you rotate the shaft manually, are you supposed to be able to
hear/feel any friction? Because you can on ours - you can hear a sort of
rubbing sound.
If it is the bearings, what can be done about it? Can you replace them?
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from rhan...@nospamsk.sympatico.ca
Home Page: http://www.geocities.com/TimesSquare/Arcade/9967/
John Mills
>
> Lately the blower on our 1970s Lennox gas furnace has started to make an
> annoying, rhythmic rattling sound. It only seems to happen when the furnace
> is cool (like after the burner has turned off but the blower is still
> running). I checked for anything rattling around in the blower housing, and
> tightened down the bolts on the rubber mountings, but it didn't help. You
> can make the same rattling sound if you grab the part that the motor and
> blower shaft sits on and jiggle it around. Could this be the bearings on the
> blower shaft that are worn out and allowing the shaft to rattle around?
Is this a belt drive system? If so, the blower would have replacable
bearings
and that could be the problem. But it shouldn't be only when the furnace
is
cool, I'd expect it to be all the time. A direct drive system would not
have bearings you can do anything with, you would have to change the
motor.
Not a cheap prospect with a Lennox which usually uses a special size
motor.
Blower wheels can fail and make noise, again should be all the time
though.
> Also, when you rotate the shaft manually, are you supposed to be able to
> hear/feel any friction? Because you can on ours - you can hear a sort of
> rubbing sound.
On a belt drive, more likely to hear & feel. On direct drive, usually
would
be smooth & quiet.
> To email, remove "nospam" from rhan...@nospamsk.sympatico.ca
Too much work
--
HVAC Advice, Pictures, Links
http://www.geocities.com/~johnmills
http://www.appelheat.com
cfans
however Lennox often built their own blowers using wheels from a mnufacturer
like Lau (at least they did from 1980 on as far as i recall).
Therefore the bearings may be Lau sleeve bearings, or they may be Triangle
sleeve bearings, either type available from an HVAC wholesaler, in your area
try Werners.
IMPORTANT, the shaft must also be replaced, this means takin the whole darn
thing apart. Maybe get a local hvac guy to look at it.
Mike
cf...@msn.com
Robert Hancock wrote in message <75emu7$bf...@dragon.sk.sympatico.ca>...
>Lately the blower on our 1970s Lennox gas furnace has started to make an
>annoying, rhythmic rattling sound. It only seems to happen when the furnace
>is cool (like after the burner has turned off but the blower is still
>running). I checked for anything rattling around in the blower housing, and
>tightened down the bolts on the rubber mountings, but it didn't help. You
>can make the same rattling sound if you grab the part that the motor and
>blower shaft sits on and jiggle it around. Could this be the bearings on
the
>blower shaft that are worn out and allowing the shaft to rattle around?
>
>Also, when you rotate the shaft manually, are you supposed to be able to
>hear/feel any friction? Because you can on ours - you can hear a sort of
>rubbing sound.
>
>If it is the bearings, what can be done about it? Can you replace them?
>
>--
>Robert Hancock Saskatoon, SK, Canada
>To email, remove "nospam" from rhan...@nospamsk.sympatico.ca
>Home Page: http://www.geocities.com/TimesSquare/Arcade/9967/
>
>
>
>
danh...@infonet.isl.net
>Lately the blower on our 1970s Lennox gas furnace has started to make an
>annoying, rhythmic rattling sound. It only seems to happen when the furnace
>is cool (like after the burner has turned off but the blower is still
>running). I checked for anything rattling around in the blower housing, and
>tightened down the bolts on the rubber mountings, but it didn't help. You
>can make the same rattling sound if you grab the part that the motor and
>blower shaft sits on and jiggle it around. Could this be the bearings on the
>blower shaft that are worn out and allowing the shaft to rattle around?
>
>Also, when you rotate the shaft manually, are you supposed to be able to
>hear/feel any friction? Because you can on ours - you can hear a sort of
>rubbing sound.
>
>If it is the bearings, what can be done about it? Can you replace them?
Is this a belt-driven or direct drive unit. If direct drive then the
bearings are about the only possibility, but if belt driven then the belt
may be the problem. But on our belt-driven 1976 furnace I've had to
replace the bearings several times.
If the bearings are the problem, check if the shaft is scored. If so, get
a new one. In most cases you can get a new shaft cut at a local shop --
you don't need to order a replacement from the factory. The bearings
likewise may (or may not) be stock items. Check with the major plumbing
parts distributors in your area for replacements.
Dan Hicks
Hey!! My advice is free -- take it for what it's worth!
http://www.millcomm.com/~danhicks
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Craig
regular ball bearing. If the shaft is only scored slightly you probably
wont have to change the shaft with these type bearings. You can probably
get either bearing at a bearing distributer.
If this is a direct drive motor, blower wheel mounted to the motor
shaft you will have to replace or repair the motor.
Craig
cfans wrote:
>
> Assuming your blower is belt drive, the bearings may likely be the problem,
> however Lennox often built their own blowers using wheels from a mnufacturer
> like Lau (at least they did from 1980 on as far as i recall).
> Therefore the bearings may be Lau sleeve bearings, or they may be Triangle
> sleeve bearings, either type available from an HVAC wholesaler, in your area
> try Werners.
> IMPORTANT, the shaft must also be replaced, this means takin the whole darn
> thing apart. Maybe get a local hvac guy to look at it.
>
> Mike
> cf...@msn.com
>
> Robert Hancock wrote in message <75emu7$bf...@dragon.sk.sympatico.ca>...
> >annoying, rhythmic rattling sound. It only seems to happen when the furnace
> >is cool (like after the burner has turned off but the blower is still
> >running). I checked for anything rattling around in the blower housing, and
> >tightened down the bolts on the rubber mountings, but it didn't help. You
> >can make the same rattling sound if you grab the part that the motor and
> >blower shaft sits on and jiggle it around. Could this be the bearings on
> the
> >blower shaft that are worn out and allowing the shaft to rattle around?
> >
> >Also, when you rotate the shaft manually, are you supposed to be able to
> >hear/feel any friction? Because you can on ours - you can hear a sort of
> >rubbing sound.
> >
> >If it is the bearings, what can be done about it? Can you replace them?
> >
RAC
unit in, Nobody keeps a car that costs $2000 for 30 years, why a furnace.
cfans
noisy, noisier than the sleeve bearing, which, when installed properly will
run for the life of the furnace
(in most cases).
Mike Cahill
cf...@msn.com
Craig wrote in message <367B1CF6...@home.com>...
>Those sleeve "bearings" are pretty cheesy. Id replace them with a
>regular ball bearing. If the shaft is only scored slightly you probably
>wont have to change the shaft with these type bearings. You can probably
>get either bearing at a bearing distributer.
> If this is a direct drive motor, blower wheel mounted to the motor
>shaft you will have to replace or repair the motor.
>Craig
>cfans wrote:
>>
>> Assuming your blower is belt drive, the bearings may likely be the
problem,
>> however Lennox often built their own blowers using wheels from a
mnufacturer
>> like Lau (at least they did from 1980 on as far as i recall).
>> Therefore the bearings may be Lau sleeve bearings, or they may be
Triangle
>> sleeve bearings, either type available from an HVAC wholesaler, in your
area
>> try Werners.
>> IMPORTANT, the shaft must also be replaced, this means takin the whole
darn
>> thing apart. Maybe get a local hvac guy to look at it.
>>
>> Mike
>> cf...@msn.com
>>
>> Robert Hancock wrote in message <75emu7$bf...@dragon.sk.sympatico.ca>...
Robert Hancock
it is the motor bearings as someone else suggested as the motor is only a
few years old and has permanently-lubricated ball bearings.
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from rhan...@nospamsk.sympatico.ca
Home Page: http://www.geocities.com/TimesSquare/Arcade/9967/
<danh...@infonet.isl.net> wrote in message
news:367b1...@news.newsfeeds.com...
>In <75emu7$bf...@dragon.sk.sympatico.ca>, "Robert Hancock"
<rhan...@nospamsk.sympatico.ca> writes:
>>Lately the blower on our 1970s Lennox gas furnace has started to make an
>>annoying, rhythmic rattling sound. It only seems to happen when the
furnace
>>is cool (like after the burner has turned off but the blower is still
>>running). I checked for anything rattling around in the blower housing,
and
>>tightened down the bolts on the rubber mountings, but it didn't help. You
>>can make the same rattling sound if you grab the part that the motor and
>>blower shaft sits on and jiggle it around. Could this be the bearings on
the
>>blower shaft that are worn out and allowing the shaft to rattle around?
>>
>>Also, when you rotate the shaft manually, are you supposed to be able to
>>hear/feel any friction? Because you can on ours - you can hear a sort of
>>rubbing sound.
>>
>>If it is the bearings, what can be done about it? Can you replace them?
>
danh...@infonet.isl.net
>Those sleeve "bearings" are pretty cheesy. Id replace them with a
>regular ball bearing. If the shaft is only scored slightly you probably
>wont have to change the shaft with these type bearings. You can probably
>get either bearing at a bearing distributer.
I enquired about roller or ball bearings the last time I replaced my
furnace bearings, and the folks at the distributors said that roller/ball
bearings tend to be much noisier in fan service. (Of course, they also
didn't have them in stock, which may have had something to do with it.)
HVACMAN
RAC wrote:
> The unit is almost 25 to 30 years old, I say get rid of it and put a dependable
> unit in, Nobody keeps a car that costs $2000 for 30 years, why a furnace.
Young Robb has been told this many times, I don't think Mom and Pop have the
cash... Hope he solved that bit of a CO problem from last season!
>
>
> Robert Hancock wrote:
>
> > Lately the blower on our 1970s Lennox gas furnace has started to make an
> > annoying, rhythmic rattling sound. It only seems to happen when the furnace
> > is cool (like after the burner has turned off but the blower is still
> > running). I checked for anything rattling around in the blower housing, and
> > tightened down the bolts on the rubber mountings, but it didn't help. You
> > can make the same rattling sound if you grab the part that the motor and
> > blower shaft sits on and jiggle it around. Could this be the bearings on the
> > blower shaft that are worn out and allowing the shaft to rattle around?
> >
> > Also, when you rotate the shaft manually, are you supposed to be able to
> > hear/feel any friction? Because you can on ours - you can hear a sort of
> > rubbing sound.
> >
> > If it is the bearings, what can be done about it? Can you replace them?
> >
Robert Hancock
chamber being kicked up into the flames and being burned off - the flames
weren't yellow like the end of the pilot flame, more orange in color. It was
worse if you have just opened up the covers and have been banging things
around. If you just leave it alone the flames are perfectly fine. No other
signs of backdrafting, sooting around the air inlet, etc. that I can see.
It is old, but at the moment there is no really compelling reason to replace
it so it'll probably be sticking around for a while yet.
Getting back to the original problem, would it be too outlandish to wonder
if one could get a whole new blower assembly with bearings, shaft, fan, etc.
instead of messing around with changing the bearings around?
By the way, it's a Lennox model G8-120, from around 1974, if anyone needs to
know.
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from rhan...@nospamsk.sympatico.ca
Home Page: http://www.geocities.com/TimesSquare/Arcade/9967/
HVACMAN <hva...@uswest.net> wrote in message
news:367DAF16...@uswest.net...
danh...@infonet.isl.net
some regularity. Replacing them can be difficult, but not particularly
expensive if you do it yourself. The shaft should generally be replaced
at the same time. However, note that often a new fan belt will tend to
squeek.
In <75gup4$c1...@dragon.sk.sympatico.ca>, "Robert Hancock" <rhan...@nospamsk.sympatico.ca> writes:
>It is a belt drive system. The belt is quite new however, and I don't think
>it is the motor bearings as someone else suggested as the motor is only a
>few years old and has permanently-lubricated ball bearings.
>
>--
>Robert Hancock Saskatoon, SK, Canada
>To email, remove "nospam" from rhan...@nospamsk.sympatico.ca
>Home Page: http://www.geocities.com/TimesSquare/Arcade/9967/
>
>
><danh...@infonet.isl.net> wrote in message
>news:367b1...@news.newsfeeds.com...
>>In <75emu7$bf...@dragon.sk.sympatico.ca>, "Robert Hancock"
><rhan...@nospamsk.sympatico.ca> writes:
>>>Lately the blower on our 1970s Lennox gas furnace has started to make an
>>>annoying, rhythmic rattling sound. It only seems to happen when the
>furnace
>>>is cool (like after the burner has turned off but the blower is still
>>>running). I checked for anything rattling around in the blower housing,
>and
>>>tightened down the bolts on the rubber mountings, but it didn't help. You
>>>can make the same rattling sound if you grab the part that the motor and
>>>blower shaft sits on and jiggle it around. Could this be the bearings on
>the
>>>blower shaft that are worn out and allowing the shaft to rattle around?
>>>
>>>Also, when you rotate the shaft manually, are you supposed to be able to
>>>hear/feel any friction? Because you can on ours - you can hear a sort of
>>>rubbing sound.
>>>
>>>If it is the bearings, what can be done about it? Can you replace them?
>>
>>Is this a belt-driven or direct drive unit. If direct drive then the
>>bearings are about the only possibility, but if belt driven then the belt
>>may be the problem. But on our belt-driven 1976 furnace I've had to
>>replace the bearings several times.
>>
>>If the bearings are the problem, check if the shaft is scored. If so, get
>>a new one. In most cases you can get a new shaft cut at a local shop --
>>you don't need to order a replacement from the factory. The bearings
>>likewise may (or may not) be stock items. Check with the major plumbing
>>parts distributors in your area for replacements.
Dan Hicks
Craig
You can probably buy the whole setup for a few hundred dollars compared
to 50/75 dollars for shaft and bearings. Youll probably have to buy the
setup in pieces and put it together anyways.
Craig
Robert Hancock wrote:
>
> Actually, I believe that was just a result of some dust in the burner
> chamber being kicked up into the flames and being burned off - the flames
> weren't yellow like the end of the pilot flame, more orange in color. It was
> worse if you have just opened up the covers and have been banging things
> around. If you just leave it alone the flames are perfectly fine. No other
> signs of backdrafting, sooting around the air inlet, etc. that I can see.
>
> It is old, but at the moment there is no really compelling reason to replace
> it so it'll probably be sticking around for a while yet.
>
> Getting back to the original problem, would it be too outlandish to wonder
> if one could get a whole new blower assembly with bearings, shaft, fan, etc.
> instead of messing around with changing the bearings around?
>
> By the way, it's a Lennox model G8-120, from around 1974, if anyone needs to
> know.
>
> --
> Robert Hancock Saskatoon, SK, Canada
> To email, remove "nospam" from rhan...@nospamsk.sympatico.ca
> Home Page: http://www.geocities.com/TimesSquare/Arcade/9967/
>
> HVACMAN <hva...@uswest.net> wrote in message
> news:367DAF16...@uswest.net...
> >
> >
> >RAC wrote:
> >
> >> The unit is almost 25 to 30 years old, I say get rid of it and put a
> dependable
> >> unit in, Nobody keeps a car that costs $2000 for 30 years, why a furnace.
> >
> >Young Robb has been told this many times, I don't think Mom and Pop have
> the
> >cash... Hope he solved that bit of a CO problem from last season!
> >
> >>
> >>
> >> Robert Hancock wrote:
> >>
> >> > Lately the blower on our 1970s Lennox gas furnace has started to make
> an
> >> > annoying, rhythmic rattling sound. It only seems to happen when the
> furnace
> >> > is cool (like after the burner has turned off but the blower is still
> >> > running). I checked for anything rattling around in the blower housing,
> and
> >> > tightened down the bolts on the rubber mountings, but it didn't help.
> You
> >> > can make the same rattling sound if you grab the part that the motor
> and
> >> > blower shaft sits on and jiggle it around. Could this be the bearings
> on the
> >> > blower shaft that are worn out and allowing the shaft to rattle around?
> >> >
> >> > Also, when you rotate the shaft manually, are you supposed to be able
> to
> >> > hear/feel any friction? Because you can on ours - you can hear a sort
> of
> >> > rubbing sound.
> >> >
> >> > If it is the bearings, what can be done about it? Can you replace them?
> >> >
John Barry
I'm in same situation, with hot-air unit from '57. WW Grainger sells wide
variety of replacement
furnace air-movers. Bolt-in fan frame, connect motor wiring. With
higher-eff motor, whole pkg
for abt $180. Going in soon.
Seems you mainly need to know width and diam of fan impeller. On install,
mate its discharge to
furnace heat-exchanger inlet.
HTH,
John
Craig <cmoo...@home.com> wrote in article <367DB456...@home.com>...
Tom Line
Possibly dirt build-up on one side of the squirrel cage fan putting it
out of balance. Try cleaning the fan with a brush or rag.
danh...@infonet.isl.net
dollars! Maybe US $12 apiece for the bearings and $15 for the shaft. And
throw in an extra $2 if you want to splurge and get new speed nuts.
Dan Hicks
OU812OHBOY
cost effective to have the bearings replaced, usually a generic motor of the
same rating will work just fine. Make sure that you check the blower wheel for
any surfaces that are worn to the point of possibly coming apart. If you have a
company replace the motor, expect to pay substantially more for the motor due
to retail mark-up. Larry
Craig
Ive used ball style bearings on alot of jobs replacing those bronze
bushing types without a single complaint of noise. The thought never
crosses my mind to use those bushing types. The manufactures use them
because there cheap to buy. There so pathetic that if the customer over
tightens the belt they can ruin them. The other thing is if the shaft is
worn you may not have to replace it.
Craig
danh...@infonet.isl.net wrote:
>
> In <367B1CF6...@home.com>, Craig <cmoo...@home.com> writes:
> >Those sleeve "bearings" are pretty cheesy. Id replace them with a
> >regular ball bearing. If the shaft is only scored slightly you probably
> >wont have to change the shaft with these type bearings. You can probably
> >get either bearing at a bearing distributer.
>
> I enquired about roller or ball bearings the last time I replaced my
> furnace bearings, and the folks at the distributors said that roller/ball
> bearings tend to be much noisier in fan service. (Of course, they also
> didn't have them in stock, which may have had something to do with it.)
>
Craig
Thats 43$ without tax for the crap bearings at the supply house to an
HVAC contractor. I guess you have no markup on your parts if your in
bussiness. I dont think Im that far off on the price.
Craig
Robert Hancock
called that the motor - blower assembly is mounted on are worn out and
allowing the assembly to rattle around against the bolts that hold them on.
They certainly feel pretty soft and flabby. Apparently they have these
rubber things at a local HVAC place so we will get ahold of some of these
and see what happens.
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from rhan...@nospamsk.sympatico.ca
Home Page: http://www.geocities.com/TimesSquare/Arcade/9967/
Robert Hancock <rhan...@nospamsk.sympatico.ca> wrote in message
news:75emu7$bf...@dragon.sk.sympatico.ca...
danh...@infonet.isl.net
There's a 30% premium if I'm wearing business attire.
Dan Hicks
WB or CM Hilbrich
: Possibly dirt build-up on one side of the squirrel cage fan putting it
: out of balance. Try cleaning the fan with a brush or rag.
*** Had a similar problem several years ago.... When we finally took a
look inside, we found that a tiny price ticket from one of the replaceable
air filters had gotten inside, and that was enough to knock the fan out of
balance.....
Bill
--
=============================================================================
Bill Hilbrich St. Cloud, Minnesota hilb...@cloudnet.com
" It's A Magical World, Hobbes, Ol' Buddy... ...Let's Go Exploring ! "
Calvin's Last Words 12/31/95
=============================================================================
Robert Hancock
mountings, adjusted the endplay, and I put a wad of cardboard & masking tape
between part of the blower chassis and the shock-mounted frame that may have
been vibrating against each other. This seems to have solved the problem..
--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from rhan...@nospamsk.sympatico.ca
Home Page: http://www.geocities.com/TimesSquare/Arcade/9967/
Robert Hancock <rhan...@nospamsk.sympatico.ca> wrote in message
news:75otfo$du...@dragon.sk.sympatico.ca...
Mel Damron
This becoming dangerous is not likely. However if gone unrepaired
should the blower completely malfunction and saftey devices fail...
Well, yes then it could be very dangerous!
It would be a good idea to have your furnace/air handler serviced at
this time. Perhaps it's just looses nuts and mounts and better to
correct a simple problem than create a much large one. And beside's
Anita isn't the nouise annoying? Let us know what your serviceman
finds...
Mel Damron,AllTemp Heating & Cooling
anita wrote:
>
> x-no-archive: yes
> Noticed the question re: heating blower rattling .. mine is doing it
> sometimes .. and then 'settles' down ..I think it's unbalanced a little
> .. can this be dangerous ? It's in the attic and is working just fine
> ...
> many thanks ..
> 'nita
Mel Damron
This brainier came over me also... It's possible your blower wheel has
loosed on it's shaft and only needed tightening? Just an after thought
to check out in addition to all the other suggestions this subject has
recieved.
> ------------------------------------------------------------------------
>
> Name: vcard.vcf
> vcard.vcf Type: VCard (text/x-vcard)
> Encoding: 7bit
> Description: Card for Mel Damron