Why Your Extractor Fan Isn't Working Properly

Extractor fans prevent damp, mould, and cooking smells. When they stop working, problems build up. Here's how to diagnose what's wrong.

Quick Diagnosis

Fan Not Running at All

Check:

• Is there power? (Has it tripped? Switched off somewhere?)
• Is the isolator switch on? (Often a pull cord or switch)
• Is the timer working? (Some fans run on delay)

Likely causes:

• Blown fuse
• Faulty isolator
• Motor burnt out
• Wiring issue

Fan Running But Not Extracting

Check:

• Is air actually moving? (Hold tissue to grille)
• Is the external vent blocked?
• Is the ducting connected?

Likely causes:

• Blocked vent flaps
• Bird nest in external vent
• Ducting disconnected or crushed
• Wrong fan for the space

Fan Noisy or Vibrating

Check:

• When did noise start?
• Continuous or intermittent?
• Does it stop if you touch the grille?

Likely causes:

• Worn bearings
• Debris on blades
• Loose mounting
• Blade damage

Fan Not Switching On with Light

Check:

• Does it work on its own switch?
• Does the overrun timer still work?

Likely causes:

• Faulty connection at light circuit
• Timer module failure
• Wiring disconnected

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Simple Fixes You Can Try

1. Clean the Fan

Grease and dust clog extractor fans.

How:

1. Turn off power at fuse box (essential)
2. Remove grille cover (usually clips off or unscrews)
3. Vacuum dust from around the motor
4. Clean blades gently (damp cloth)
5. Clean grille in warm soapy water
6. Let everything dry before refitting

How often: Every 6-12 months

2. Check the External Vent

Outside your house:

1. Locate where the duct exits
2. Check for blockages (leaves, debris, bird nests)
3. Check the flap opens freely
4. Clear any obstructions

Common problem: Vent flaps seize shut with dirt and age.

3. Test the Isolator

Pull cord or switch for the fan:

1. Turn off, then on
2. Listen for any sound
3. If nothing, the fan or isolator may be faulty

4. Check Connection to Light

If fan should work when light's on:

1. Does the light work?
2. If light works but not fan, connection issue at fan end

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Understanding Fan Types

Manual Fans

Turn on with a separate switch or pull cord.

Simple to operate but relies on people using them.

Light-Activated Fans

Come on when light is switched on.

Usually have an overrun timer - keep running after light off.

Humidity-Activated Fans

Detect moisture and switch on automatically.

Best for bathrooms, but sensor can fail.

Timer Fans

Run for set time after activation.

Common with light-linked fans - overrun clears moisture after showering.

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When It's an Electrical Issue

Signs of electrical problems:

• Fan trips the circuit
• Burning smell
• Fan runs slow then stops
• Buzzing without motor running

DON'T try to fix these yourself. Electrical work in bathrooms requires a qualified electrician.

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Fan Replacement

Sometimes fans just wear out.

Signs You Need a New Fan

• Motor hums but doesn't spin
• Runs but barely moves air
• Extremely noisy despite cleaning
• More than 10-15 years old

Types of Replacement

Like-for-like: Easiest. Same size hole, same connections.

Upgrade: May need different hole size, possibly different wiring.

DIY-able? Replacing a like-for-like fan can be DIY if you're comfortable with basic electrics. New installations are Part P and need an electrician.

Fan Costs

Budget fan: £15-£30 Mid-range: £40-£80 Premium (quiet, humidity sensor): £80-£150

Installation: £80-£150 for a replacement, more for new installation with ducting.

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Is Your Fan Powerful Enough?

Fans are rated in litres per second (l/s) or cubic metres per hour (m³/h).

Building Regulations minimums:

• Bathroom: 15 l/s
• Kitchen: 30 l/s adjacent to hob, 60 l/s if part of cooker hood

Reality: A tiny fan in a big bathroom won't clear steam effectively.

Check your fan rating against room size if you have persistent moisture issues.

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Ducting Issues

Problems with the pipe connecting fan to outside:

Disconnected Ducting

Symptoms: Fan runs but room doesn't clear

What happened: Flexible duct has come off spigot - common in lofts

Fix: Reconnect and secure with tape/clip

Crushed Ducting

Symptoms: Poor extraction despite fan running

What happened: Flexible duct got squashed (in loft, by boxes, etc.)

Fix: Replace or redirect duct

Long Run or Too Many Bends

Symptoms: Fan can't push air through effectively

What happened: Over-ambitious routing when installed

Fix: May need more powerful fan or shorter route

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When to Call a Professional

Electrician needed for:

• New fan installation
• Wiring issues
• Fan trips the circuit
• Changing fan type/controls

Handyman can help with:

• Cleaning and maintenance
• Unblocking external vents
• Simple like-for-like replacement (depending on local regs)

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Extractor fan playing up? I diagnose and fix fan issues across Exeter. Call 01392 964094 or get a quote.