OK, here's my long tail... er, tale....
I'm doing some fix-up work at a house, and learned that the furnace has
been off for 3 years. The furnace is in a closet next to the water
heater. Both sit on a raised section in the closet about a foot from the
floor. The furnace draws air from the hallway through an enclosed box
that is underneath both furnace and water heater.
It turns out that the water heater had leaked and was then drained and
disconnected, and a new water heater was installed in the garage. I
didn't see any sign of water damage inside, outside or from underneath,
and don't see or smell any mold anywhere, including in the box.
Still, I'm hesitating firing up the furnace because I don't want it to
spread any spores through the ducts and into the rest of the house. If
the house was empty, I would open the windows and run it long enough to
purge it out. But the house is being lived in with the usual furniture,
So what I'm thinking of doing is closing all the vents and sealing them
except the one nearest the furnace, and then connecting a large OD hose
from the vent to outside thru a window. Then emptying a few cans of
Lysol into the intake area and running just the blower for awhile. Then
turn on the furnace and run that for awhile. Then seal that vent, and
repeat the fan & furnace with the next closest vent, until all the ducts
I first tried rigging up a box to cover the vent with a vacuum cleaner
hose, and then running the vacuum, but the blower puts out way more air
than the vacuum can handle.
Anyway, that's my story. Does anyone have any ideas of a better way to
be sure the ducts get reasonably dust-free?
Thanks in advance!
On Mon, 15 Dec 2014 23:08:53 -0800, "Sasquatch Jones"
air than the vacuum can handle.
Personally, I'd just change the furnace filters, wipe out the furnace
and try to wipe out the inside of the blower as much as possible (with
the power off), and then start the furnace. Just because the furnace
has been off dont mean the ducts fill with dust.
But if this is a real concern for you, there are companies that do duct
cleaning. That would remove everything that has built up over the
years. But it may be costly ???
Call them and find out!
A bigger concern is to be sure the burner is not leaking carbon
monoxide. Get a Carbon Monoxide detector or have a furnace guy look at
it. If this is an oil furnace the oil filter and nozzle could be
On 12/16/2014 03:22 AM, firstname.lastname@example.org wrote:
Yep. Check the heat exchanger.
Vacuum everything out and put in a new filter.
CO detector is a generally good idea.
BTW: I did have a professional service clean the ducts once . Don't
recall the price but it was not too steep.
On Tuesday, December 16, 2014 4:23:03 AM UTC-5, email@example.com wrote:
I would just do a filter change and normal service inspection. I
wouldn't wipe out anything. For one thing, you can't get to enough
of anything inside the furnace air system that it matters. Second,
as you say, just because it's been off, doesn't mean the furnace is
going to somehow fill with dust. Dust has to come from somewhere and
get in there.
I agree. They can clean the ducts, but even they aren't going to get
inside most of the air handler of the furnace. Just because the WH was
leaking, if there is no damage around the WH, no mold visible, etc,
that wouldn't make me worry about the furnace ducts.
If he's worried, how about taking some grills, registers off and taking
a look? Any evidence of mold or abnormal dust in the filters, in the
easily visible part of the blower compartment?
And if there is a problem, I doubt the lysol approach is going to do much
to solve it. I'd also be concerned about choking off almost the whole system
and trying to run the blower.
Yes, normal inspection is what I'd do. I'd expect you'd get a little
smell of some kind on the first start. I notice that sometimes. But
absent some reason to really expect trouble, I doubt there is going to
be a problem.
The problem with that approach is that the occupants will end up
evacuating the house, gasping for breath from the Lysol fumes.
Seriously. It's a bad idea. Just clean the furnace and the ductwork,
forget about any kind of antifungal treatment whether DIY or
professional. The EPA does not recommend them.
Aren't mold spores practically everywhere anyhow? Mold is not like
ants, who send out scouts looking for something to eat, and then notify
the hill when they find something.
AIUI if there were mold anywhere in the house, or the neighborhood, ,
spores would already be everywhere in the house. But the mold ony grows
where the environment is suitable. The reason it grows where the
environment is suitable is that were spores there in the first place.
And even if the mold grew where the water heater was, all the water
dried up a long time ago and the mold died. That a wall is still
black doesn't mean the mold is alive. Mold doesn't have pall bearers or
family who come and paint a wall white again.
So there are no more spores in the ducts than there are in the rest of
the house, the same air they'r e breathing now.
On Tue, 16 Dec 2014 05:26:41 -0800 (PST), trader_4
I woundn't even consider that Lysol, that odor might never go away.
On the other hand, why not wipe out the furnace. When I moved into my
house, the furnace area around the blower was filthy. I bucket of
water, sponge and a little dish soap cleaned it really nice in a half
hour. On my case, I removed the blower, took it outdoors and hosed it
out. I did nothing with the ducts except vacuum inside each register.
Most what I found was small parts of kids toys, and a few coins.
On Wednesday, December 17, 2014 4:01:48 AM UTC-5, firstname.lastname@example.org wrote:
I doubt that with most furnaces today you could remove the blower, hose
it out and put it back together in half an hour. And it seems fairly
pointless anyway. All you're getting at is a small part of the furnace,
none of the duct system. Even in the furnace, there is a lot more than
the blower. The heat exchanger is usually totally inaccessible
We live in a society filled with fear. Much is based on lies and
exaggerations based on advertisers wanting to get our money. Molds have
been around since the beginning of time. You cant avoid them. Sure,
there are some proven to be harmful by scientists and medical people,
but only certain molds. They have been around forever too, but it's
because of tight sealed newer homes concentrating them (which is one
reason I'd not want to cover my walls with plastic sheeting, under the
sheetrock). [Just my personal choice].
Before over reacting to molds, and even asbestos and stuff like that,
get FACTUAL information, not bullshit created by advertisers. After
all, there appears to be big money to be made, if these companies find a
sucker to pay them to dress up in all sorts of space suits, and hang
plastic all over your home, and in the end, run a vacuum cleaner. I
often wonder how much of this is just putting on an theatrical act,
versus really doing something useful.
If the OP has had a leak which caused black mold (that seems to be the
bad one), then have a reputible company test for problems, and be sure
they are certified and all of that. Then remove the decayed material
and repair. If there was no problem to start with, why fear something
that is normal. People who live in a totally sterile enclosure will be
the first ones to become severely ill if there is a flood, hurricane
damage, etc. You need to be immune to these natural molds and stuff, by
normal small daily doses. Same as how a flu vaccine works, you get a
small dose so your body builds up immunity.
So, unless there is a problem, just change the filters, clean the
furnace, and check the registers. If the ducts are filthy, have one of
those companies clean them. Clean them mostly just to remove the dirt,
not being so concerned about molds and so on. If nothing else, cleaning
the ducts will reduce dusting stuff in the house. All of this depends on
the age of the hoem, cleanliness of previous owners, and other stuff.
My house had a leak in one place and there was some black mold. As soon
as I moved in, I opened all the windows in summer, blew a fan outward
and removed the bad sheetrock, wood, insulation, and other materials.
Any wood that remained inside the walls that looked a little moldy, I
washed with strong bleach water. Then I repaired the stuff and
vacuumed/cleaned the house or any remaining dirt as well as sawdust and
stuff from doing the repair. Every spring I like to completely air the
house out by opening windows and blowing a fan outward. My parents did
it, and I used to think everyone did it.
Levels were not extreme enough. Some rooms got separate treatment. Hvac ran
as normal, mostly cold months. You could get fairly high smelly fresh
ozone, but the ozone is easy to smell without being corrosive. Chlorine
dioxide can cause bleaching near dispensers.
They generally produce some ozone, but not that much. Uv kills upon
Some water treatment plants use large uv lamps to purify water. ozone
generators just use high voltage ac corona on plates and use fans or pumps.
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