we have forced air heat, when the heat runs there is
a harmonic whine that resonates through a few parts of
the house (which isn't very large at all anyways). i
am lucky in that i'm in the offside room which doesn't
hear that noise, but Ma is going to keep gnawing on me
to fix it for the next six months if i don't figure it
when i crawl down below to find the noise it isn't
there at all. i've checked all vents, nothing changed
with those being in or out.
i thought of sticking a rag on the end of a hose and
putting it down each vent a bit and hoping i can narrow
it down to a specific run of duct work.
any other ideas to figure this out?
I had a similar problem in a 1972 house. It had a gas furnace with the
flue pipe going up through a chase behind a living room wall. When the
gas would 1st turn on, it started making a noise like an airplane and
then, once the heat exchange warmed up, it would go away. I had the
original installer back several time, however, it would never make the
noise when they were there. It seemed to happen only after a long cool
down. I finally recorded the noise for them to hear. The 1st guy to hear
the recording said, we'll replace parts until the sound goes away. His
1st guess was to replace the entire set of burners. Problem solved!
Never happened again for the rest of the furnace's life.
If the resonance goes away when you go down to investigate, be sure to
close the door or whatever after you go down. Resonance in sheetmetal
ductwork is affected by air pressure on both sides, and opening a door
to space that is normally sealed can affect it. Once you find the panel
that is resonating, you can just screw a piece of wood to it with a
couple sheet metal screws to change the resonant frequency and eliminate
i would guess AC as it is a part of the furnace,
but it isn't easy to get to (it is also under the
we didn't notice it this summer when the air
condition ran, but perhaps it was there but just not
as noticeable now that we've had things off for a
i just turned the air conditioner on to see if that
made any difference and the noise is still there
aka no change.
electricity to run the blower from
the power company. propane is burned
1 story hexagon shaped house for the main
part. each facet supported by a beam which
runs up to the central fire place which is
field stone. the foundation is cinderblocks
around the perimeter with a central line
running down the middle which also goes under
duct work under the house, none in the walls.
1 small enclosed bathroom next to the fireplace
and another small walk through master bath next to
that but the doors on both sides of that are usually
open. the master bedroom is open above the other
two bathrooms so that airspace connects to the rest
of the main area (living room, kitchen). my room
is off the north facet.
i've done a lot of sealing up around the exterior
foundation but that is external.
yes, all have been removed and checked while the
furnace was running, no change in noise.
yes, ran it to see if that made any difference,
nope, noise still there.
I had an intermittent 60 hz type of hum, after weeks of trying to chase it
down, thinking it was electric related, I eventually found that it was the
gas meter and it was transmitting the sound through the gas pipes only when
the furnace was running. The gas company changed the meter and all is quiet.
You have propane, no meter, but check out the regulator that reduces the
pressure, sometimes they will make a hum or whine sound and it may need
this is a high pitched whine and it is consistently
there (with some variation which resonates).
the burners have been replaced and the blower was
replaced within the past few years. this noise is
not coming from the area where the heater is at, it
is a high pitched resonant vibrational noise, like
if you rubbed your finger over the edge of a glass
like they do to make music.
um, manual blower switch?
like if i turn on the fan at the thermostat control?
i would guess it will come on like any other time
the furnace or air conditioning turns on.
if you mean instead, like, i have to be down in the
crawl space and find some switch on the furnace, well
i don't mess with that yet. i suspect that there will
be no change.
it's not easy for me to get down there so line up
things to do to check and after a few more days of
suggestions and me trying other things, if i haven't
gotten it solved by then, then i'll head down with the
list and see what happens. as i cannot hear the whine
down there it would involve some type of cooperation
and signalling from Ma if any change happens and she
isn't always as patient about such things... it may be
fun, or a challenge or a distaster. we'll see... :)
was happy to get the front door weather strip
replacement project done today. gardening tomorrow
and maybe testing some ducts with hose and rag to
see what happens.
I have a story about a high pitched whine.
I heard it about 3:00 AM when everything was quiet. It wasn't a smoke dete
ctor's beep, but could have been one malfunctioning and whining very quietl
y, or something similar.
I searched the whole house. The whine was everywhere, but impossible to lo
cate. But it was much louder near the ceilings, which were hard plaster (o
lder house). Yes, I got the ladder out and checked all the rooms.
So, climb into the attic, which was unfinished and had loose fill insulatio
n, no noise. How can this be? Louder near the ceiling, but nothing in the
Maybe it's coming in from outside. Nope. (quiet neighborhood, no traffic
at all that time of night)
So I repeated the search several times, climbing ladders, going into the at
tic, going outside and scratching my head, same results. Tired as I was, I
couldn't let it go, couldn't think of anything else to try except keep doi
ng the same thing that wasn't working.
Did I mention I'm right handed? I have a couple left handed kids but I am
strongly right handed.
So when I'm standing outside thinking about it, I'm scratching my head with
the right hand. And wondering why there is zero noise outside.
AND THEN: I scratch my head with my left hand. EUREKA! My digital watch
had malfunctioned and was emitting the tiniest whine, impossible to locate
but easy to hear in the dead quiet of night, especially when reflected by a
hard plaster ceiling, and easily absorbed in the attic or outside.
EUREKA! My digital watch had malfunctioned and
was emitting the tiniest whine, impossible to
locate but easy to hear in the dead quiet of
night, especially when reflected by a hard plaster
ceiling, and easily absorbed in the attic or outside.
One morning, I put in my hearing aids, and there
was a loud high pitch noise. Took me a while to
find it. Teakettle blowing steam. I'd put it on
Christopher A. Young
Learn about Jesus
I had a slight, barely audible buzz show up in my system a couple of years
after I had a new branch duct run from the plenum to more effectively
cool/heat a refinished downstairs space. I finally tracked it down to a
damper in the 12" square duct which I had adjusted but hadn't tightened
down afterward. Honestly, I never thought that the wing nut on the lever
A switch on the thermostat to turn the fan on counts as a manual swiwth to
most of us folks. I was trying to find out if the noise was there whenever
the fan was running, or if the noise was there ony whenthe fan was running
due to heated or cooled air. Heated or cooled air would change the dimens
ions of the metal air plenums, that might start or stop the noise. You mu
st investigate all possibilities.
of course, :)
next time i get moving again i'll see if the
noise is there when the furnace switches on but
_before_ the blower comes on. my guess is that
it will be only when the blower is on because
not much else is happening for a few moments
while the heat exchanger is heating up.
it is outside the house and the pipe is
insulated with spray foam and caulk. i
will have a listen out there when get a
chance in the next week or so. right now
gardening is kicking my ass for the next
i did this before and the noise was there that
this morning the heat came on and i stood there
and listened again to make sure that the noise is
only there when the blower comes on. yes, that is
the case. which is what i suspected before, but
wanted to verify.
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