I'm using a $20 household fan 24/7 to ventilate a damp crawl space by
sealing it against one of the crawl space vent (i.e. becomes an exhaust
Eventually this fan is going to fail, perhaps the bearings wear out and then
the fan stop spinning.
Should I worry about a fire, or do all UL listed fan have some sort of
Is there some sort of fan that is designed to run 24/7 and is well protected
I read of household fans being a fire hazard long time ago. Only reason
I remember is because my hubby likes to leave them running, 24/7, even
when the room is not occupied.
If you are planning a permanent installation, then find a fan built for
the purpose that runs on a timer. Constant circ. seems a waste - just
periodic to sufficiently move the air. Is the crawl space sealed up
with moisture barrier?
It probably depends on the fan. Some of the newer ones I've taken apart
have a thermal fuse in line with the run windings. If the fan stops for a
sufficient enough period of time, the solder inside of them vaporizes off,
and the fan no longer functions.
That is true and they stink for a while before the thermal blows.
I have seen lots of these $20 box fans fail. They were very popular in
computer rooms to fix design failures and cool "hot spots". They were
generally run 24/7 and ignored until they stopped. You will get 3-4
years out of one from my experience. You can try lubing the bearings
when they start binding up but that will not last long. Once those
oilite bearings lose their initial load of lube, they are done.
The solder is what is inside of the thermal fuse, and when it vaporizes, the
thermal fuse goes open permanently and the fan is meant to be thrown away.
My apologies for not explaining that a little better first time.
That's a better explanation. The thermal fuses don't always
use solder or more correctly a eutectic alloy sensitive to
a particular temperature. Many thermal fuses use a set of
contacts and a spring held in place by a thermoplastic resin
pellet which melts at a specific temperature allowing the spring
to pull the contacts apart. To vaporize even a soft metal such
as solder would require extreme temperatures. You had me worried
there for a minute. I could just see flaming box fans in homes
around the world.
Well, it doesn't vaporize. The temp for that is in the thousands of
degrees, I think. In a fuse that uses solder, the solder melts, at a
temp a little lower than the rated temp of soldering irons. Then it
falls away from the wires at either end of the fuse and doesn't
connect them anymore.
*You need a fan that is rated for damp or wet environments and is also rated
for continuous duty. The inline fans from Fantech have both of these
ratings. As RBM suggested you can check Grainger for a variety of choices.
You could also take a look at McMaster-Carr's website. They may have
You are using a portable temporary fan as a permanent installation. There
is definite cause for concern over the long term.
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