Microwave
Vent Fan Not Pulling Steam
A microwave vent fan not working lets steam and smoke from the pans roll up past the door, runs but moves little air, will not turn off, or switches on by itself, and it belongs only to a microwave mounted above the cooking surface.
Mon–Sat, 8am–8pm
- 5 checks before you book
- 5 questions that narrow it
- 6 causes, cheapest first
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What it
usually means.
A microwave hood combination has two fans: a small cooling fan that runs whenever the microwave heats, and a larger vent fan that draws air from under the unit through grease filters and pushes it out through a duct to the outside or back into the kitchen through a charcoal filter. The vent fan has its own keys, speeds and often an automatic mode: a heat sensor underneath switches it on when a pan below gets hot and keeps it running until the heat drops, to protect the microwave's electronics. That mode surprises owners, and a fan that will not shut off while the burners are hot is usually doing its job. A fan that runs but does not draw has clogged grease filters, a charcoal filter past its life, a damper stuck shut in the duct, or a unit set up to blow one way while the duct runs another. A fan that does not run at all points to the motor, a cutout on it, the switch or relay, or the board. The fan and its wiring sit inside the outer case, next to the high-voltage section.
The 6 causes, cheapest first
Answer these first
Does the fan not run at all, run weakly, or refuse to turn off?
Does it switch on by itself when the burners run on high?
Are the grease filters under the microwave packed with grease?
Does the air leave the home through an outside cap, or come back into the kitchen through the grille above the door?
Does the microwave itself still heat normally?
Check these
before you book.
Microwave vent fan not working: 5 checks, and none of them costs anything.
Slide out the grease filters, soak them in hot water with a degreasing soap, and let them dry before they go back.
Turn the burners off and let the area cool; if the fan then stops, the heat sensor was running it on purpose.
Try every fan speed key, and check whether air reaches the outside cap or the grille above the door.
Also worth checking
- On a unit that recirculates, check how old the charcoal filter is; many makers suggest a new one every six months to a year.
- Tell us what the fan does and does not do, and send the model number from the label inside the door frame.
How soon does it need a visit?
Not urgent in itself, but cook with care until it works: without the fan, heat and grease from the pans rise into the bottom of the microwave, and packed filters over a flame can catch. Keep the burners moderate and a lid close at hand until it is repaired.
The causes,
cheapest first.
6 things microwave vent fan not pulling steam turns out to be, from automatic heat sensing doing its job to a fan relay or key on the board.
The cost guide-
01 no repair
Automatic heat sensing doing its job
The sensor under the unit starts the fan when the pans below get hot and holds it on until they cool, whatever the keys say. Turning the burners down and waiting is the test.
-
02 no repair
Grease filters packed shut
Mesh filters thick with grease pass little air, and the fan roars while steam still rises past it. They slide out by hand and soak clean in hot water with a degreasing soap.
-
03 lowest
A spent charcoal filter
On a unit that recirculates, the charcoal filter behind the top grille clogs and stops holding odors. It cannot be washed and is replaced by model number.
-
04 low to moderate
A damper stuck or a duct blocked
The flap in the duct or at the outside cap can stick shut with grease, paint or a bird's nest, and a duct crushed in the cabinet above chokes the flow.
-
05 moderate
Fan motor or its cutout failed
A motor that hums without turning, turns slowly, or stops after a few minutes has worn bearings or an open cutout. It is replaced with the unit on the wall or taken down, depending on the model.
-
06 moderate
A fan relay or key on the board
When one speed works and another does not, or the fan will not start from its key but runs on automatic, the relay or the keypad is the suspect.
What else
it could be.
Most often confused with microwave light out inside or underneath, then loud hum, buzz or grinding from a microwave.
All problemsCodes that come with it
F3T3JennAir · Sensors and temperatureF7E9JennAir · Fans and ventilationF2H1JennAir · Fans and ventilationF8E5JennAir · Sensors and temperatureChange the Charcoal FilterKitchenAid · Fans and ventilationF2H1KitchenAid · Fans and ventilation
Also related
The makes
it happens on.
18 makes on this site; microwave vent fan not pulling steam can show up on any of them. Each mark opens that make's own page.
All 18 brandsMicrowave Vent Fan Not Pulling Steam,
where we come out.
9 metros, each with its own page.
All service areasTampa BayFL · 31 areas
Miami / South FloridaFL · 47 areas
New York MetroNY · 75 areas
HoustonTX · 36 areas
ChicagoIL · 50 areas
Los AngelesCA · 95 areas
San DiegoCA · 31 areas
Questions about
microwave vent fan not pulling steam.
Why does my microwave fan come on by itself?
How often should the grease filters be cleaned?
Can a microwave mounted over the burners vent outside?
The fan is loud but hardly moves any steam. Why?
Back to your everyday
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