For the past year I've been doing most of the cooking and a lot more home cooking than we ever have done--probably involving more grease and cooking oils than before. A few weeks ago, the range hood fan quit blowing--it only hums when I push the button.

The outdoor temperature here had dropped to 20F a few weeks ago and I'm wondering if, perhaps, there was a grease build up on the motor causing it to gum up. Now that it's consistently stayed at a daytime temperature of 50 to 60F, is it possible that it's helped free the motor?

Last night, it started working and I let it run for a few minutes. This morning it's still working. I put a service call in two weeks ago and the appointment is for tomorrow morning. I'm not sure if I should cancel it.

This question is about freeing the motor to run, if possible, and nothing else.


2 Answers 2


Yes, cold weather and hardened, cold grease buildup can conspire to stop your fan from starting.

That's "the answer to the question you asked."

The fact that you have enough grease buildup to keep the fan from starting when it's cold means that it needs to be cleaned, and possibly lubricated. That can be a DIY job, or a different, specialized contractor (most restaurants are required to have their hoods cleaned several times a year by a specialist contractor in hood-cleaning.)

It's almost certainly NOT the "fan motor replacement contractor's" job, unless they are more of a generalized hood-vent service contractor. Even if the one company does it, it would likely be two different workers with jobs that intersect but don't overlap.

  • Yes on both sections of the answer some fans are shaded pole and larger commercial are usually TEFC (totally enclosed fan cooled) with bearings. cleaning and lubricating is done in some cases bearing replacement others but that is commercial. most home exhaust fans are oil light bushings and they need a good cleaning then lubricant that is food grade approved.
    – Ed Beal
    Mar 15, 2021 at 16:34

Most of fires start in kitchens, caused by electr(on)ic devices/appliances.

Of course, this fan must be inspected/repaired/cleaned/exchanged, whatever is a safe solution. The combination of accumulated grease/oil (filter, housing, surfaces) and electric problems like sparking, stray current, hot wires by loose contacts etc. could start a fire hazard.

Even if the circuit is protected by an AFCI and/or GFCI.

The fan must be disconnected from the electric net until the maintenance/repair works.

  • 2
    My question is about getting the motor to run if at all possible, not electrical safety.
    – Rob
    Mar 15, 2021 at 11:09
  • 1
    A fan running fine in a fire is worth less than the house still standing when it gets repaired. Mar 15, 2021 at 11:46
  • 3
    The point, @Rob, is that yes you should go ahead with your appointment to get your fan serviced even though it's started spinning on its own again. There is, likely, more than enough grease, dust, and other crud built up to cause a fire. A service for the fan motor should include a good, thorough cleaning to remove this buildup and that will help reduce the chance of a fire in the future.
    – FreeMan
    Mar 15, 2021 at 11:59
  • 1
    @FreeMan Is that what they typically do? Clean the motor?
    – Rob
    Mar 15, 2021 at 12:02
  • Having not had a service cal to take care of a vent fan, I can't say what one "typically" includes, but it would be good to have it thoroughly checked out. The tech may clean it for you or recommend that you do so, but either way, at least you'll know that it's not likely to start sparking on you any time soon when he's done. Even if he doesn't clean the whole vent hood, you probably should when he's done.
    – FreeMan
    Mar 15, 2021 at 12:05

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