So I’ve read that if you interrupt a dryer when it is mid-flow (still in the heating cycle and drying the clothes, not yet cooled down), that it poses a fire hazard because it allows the temperature to suddenly spike within the lint-duct whereas as long as the dryer was continuously running, the moving airflow prevented temperatures from reaching any ignition point. Is that accurate?
(It used to be a bad habit of mine to interrupt dryers mid-cycle)
Not really.
There is a significant danger of fire in clothes dryers, but stopping them mid cycle doesn’t seem to be one. If the lint was to get hot enough to ignite then so would your clothes, since lint is just clothes dust. The bigger risk of fire comes from lint actually coming into contact with the heating element. And this is usually from an excess buildup from clogged vents.
Yes this is true.
I doubt that it would be likely to affect machines in the home unless they are large, but if all the wrong conditions were met I imagine it could happen - add in a little bit of user…er… opportunity because people do odd things.
The drying cyle consists of two parts, the heating time, the cool down time. Dryers are not that sohistication, certainly not home ones - but neither are most inudstrial ones.
They almost all operate on time, instead of outflow humidity.
If you have a large load of heavily moisture retaining material, esppecially of man made fibres then it may not dry fully before the cycle has stopped and the heated moisture will tend to concentrate toward the centre of the load - the cool down cycle will dissipate enoughheat to prevent spontaneous combustions.
If you interrupt the cycle, then the cool down phase will be bypassed.
So the worst combination is a load of dense, man made fibres that has not spun out the moisture all that well (perhaps also overloaded) , a fairly long drying cycle, interrupted fairly close to the end of the drying time but before the cool down and then leaving the dryer door closed.
It is just about possible to the load to self ignite once removed from the machine but it is etremely unlikely - you’d need a large load for that and domestic appliances are generally not that big.
You coul also add in things such as machine faults - such as temperature controller inaccuracy, and just the dumb things people do and yes it is possible.
Industrial dryers are different altogether, the operatives will adjust the cool down time to improve productivity and then leave the final load in the drum when they go off shift and then you have a fire.
I read the fine manual, and the manufacturer of my previous dryer specified spontaneous combustion from bypassing the cool-down cycle as the specific fire risk, just as @casdave said.
I’ve been interrupting the dryer in mid-cycle for years and my house is still standing. I know that you have to keep the lint trap in the dryer clear (I do it after every load) and also make sure the duct and duct opening outside is cleaned out (my husband’s job - every 6 months or so).
Same here. I check my clothes every ten minutes or so, removing things like t shirts while they are still damp, then hanging them to dry completely.
I checked the manual for our dryer (LG, purchased 2014).
In the generic safety warnings section, it warns against trying to dry “items exposed to cooking oils” and "items that have been previous cleaned/washed/soaked in gasoline or other flammable substances. Seems sensible enough, though not entirely germane to the OP.
In the specific “How to Use: Operating the Dryer” section, they point out that the “Start” button also serves as a “Pause” button. The accompanying text states: “The cycle can be paused at any time either by opening the door or by pressing the Start/Pause button.” There’s no mention at all of a fire hazard related to this.
I assume by “lint-duct” you mean everything downstream of the rotating drum. The hot air moving through this duct is the heat source, so I’m not seeing why the temperature of that duct (and its lint) would spike when the flow of hot air through them stops. ISTM these should start cooling immediately as heat is carried away from the outside of this ductwork.
If your ductwork is so jammed with lint that it reduces air flow, temperatures during operation could get dangerously high (if there were a malfunction with the thermal fuse upstream of the rotating drum), but this hazard should end when you shut the dryer off.
It would have to be an impressive clog to cause lint to actually travel upstream to the heating element while also having the thermal fuse not trip out, but I imagine somebody somewhere has managed to do this.
My dryer has the electric heating element upstream of the rotating drum, with a short section of ductwork between them (inside the dryer). The blower is downstream of the drum, which exhausts into the house’s lint duct to the outside. Lint has a tendency to escape the seals inside the dryer, and collect over time as a fine blanket covering the heater element ductwork inside the dryer.
Airflow through the heating element duct influences the temperature of the ductwork. My dryer kept popping thermal fuses inside the element duct until i replaced the drum seals around the dryer. I imagine leaky seals around the drum meant suction air was bypassing the element duct, causing increased element duct temperature.
I’m assuming a mid-cycle dyer interrupt would cause the same thing. Even powered off, the element is still hot, and the element duct no longer has any airflow-thus heating up, and igniting the fine blanket of lint that has settled above it.
An interrupted cycle would indeed mean that the residual heat in the heating element (or burner) gets dissipated into the surrounding air, and then to the surrounding outer ductwork, which may have an accumulation of lint on its exterior. The question is whether there’s enough residual heat available to raise that ductwork/lint to dangerous temperatures. Smart manufacturers will design their dryers so that this is impossible (through some combination of duct design and thermal fusing), because it’s guaranteed that a user somewhere will interrupt the cycle at some point (regardless of what the owner’s manual might tell them), and then will sue the manufacturer if a fire happens. Not ruling out that there is/was a manufacturer out there willing to design a dangerous dryer to cut a few bucks out of the price.
The most important thing is to check the owner manual for your own dryer: if it doesn’t explicitly say “don’t interrupt a drying cycle because you might start a fire”, then you probably have nothing to worry about.
Given that an interruption of electrical power to the house would have the same effect as interrupting the drying cycle manually, I would be astonished if any major appliance manufacturer’s Legal Dept. permitted a design that created a fire hazard if there were a blackout during a drying cycle. (I suppose this may not fully apply to gas-fired dryers, but my hunch is that it would apply even more stringently.)
An electrical outage would have the same effect on a gas dryer: air flow through the dryer stops, and residual heat in the burner migrates to the outer duct wall.
I’d think that it would be called out VERY clearly in the owners manuals and have warning placards on the dryer itself if it was a serious concern, i.e. happened before and a dryer manufacturer was sued.
After all every one of the dumb-ass warnings we already see on things is the direct result of some lawsuit or settlement that the manufacturers suffered. And since we don’t see anything like that about interrupted dryer cycles, it implies that it’s not something that happens with any sort of frequency.
Sounds like something somebody’s grandmother figured out in the 1950s after a dryer fire. That’s since been passed down through generations of confused homemakers.
Thanks for the answers everyone.
I have a follow-up: I’ve noticed that if I dry a normal wet load, the dryer is fine, but if I dry only 1-2 towels (a very small load,) the dryer gets very hot and emits a “hot smell.” Is this because the normal-sized wet mass absorbs heat and cools the dryer, but a tiny load only absorbs a tiny bit of heat and the dryer is therefore hotter than normal?
Not sure but I’ve been known to run a full load of completely dry clothes again to get the wrinkles out and so that they’ll be toasty and warm when I get out of the shower, all this interrupting cycles and running the dryer with dry clothes in it being dangerous just doesn’t bare out given the number of people who do this stuff everyday without issue.
Hmm - literally billions of people use road transport every day and have no need of their seatbelt. Until that time when they do.
Put another way, the reason for the disclaimers in the manuals is for if/when that rare event happens to someone, they can’t successfully sue the manufacturer for not telling them not to do whatever it was they were doing that caused the problem. But yes, if the event is rare enough, most people can go a lifetime without experiencing it.
I’d say car wrecks are far more frequent. How often do you hear about dryer fires not involving lint piling up in the trap?
Our current gas dryer is ~4 years old. I bought it at Lowe’s, brought it home on my utility trailer and installed it. I’m sure there is a manual in the drawer where we keep manuals, but I never looked at it.
Do most people read their clothes dryer manuals?
Usually I read it once or twice after we get it, just to see if there’s any cycle weirdness or unusual stuff that I might want to know about. Otherwise you’re right, it’s spin the knob, hit the button and go on about my business.
Of course they are - I was just using them as an analogy for something that’s fine most of the time, but 1 in a million times it’s not.
Of course not. But if they don’t, and then suffer some mishap that the manufacturer warned about in the manual, they’re unlikely to have much luck getting compensation.