extract fan motor making noise.
I have an extract fan motor in a kitchen and it is making noise when it is turned on in number 1 speed as you turn up the speed to number 5 the noise seems to fade and is barely heard when you turn it back to speed number 1 the noise is loud again. It is sealed in the ducting obviously i was thinking would it be the bearings in the motor or would it be maybe that the housing for holding the fan is loose. Would anybody have any experience with this sort of thing before if so i would be greatful for any information.
I am a refrigeration and air conditioning engineer but i have no experience with theese fans.
kindest regards bellaman
it's hard to say from distance, there could be different reasons for it. you can clear "lose casing" cause if you try to press casing firmly with few different powers exerted - taking care not to pull fingers through as fan blades are always dangerous.
it could also be bad static balance or the simple fact that higher frequency (at higher speed) is less annoying for your ears.
i see that often, when i specify good quality fans, but owner decides to buy cheap alternative replacement. such fans sometimes come with many nice certificates, but they are noisy as hell.
anyhow, try with looseness as first probable cause. not only fan casing, some duct clamps can be loose as well:
- try to screw all reachable screws a little tighter.
- try with elastic washers under screws, if possible.