Makes we repair
What does F3 mean?
F3 means a different fault on each make of boiler, so the make comes first. The three meanings are these:
- On an Ideal, F3 is a fan fault. The fan that pushes the flue gases out isn't running as the boiler's main board expects.
- On a Viessmann, F3 means the boiler saw a flame signal before its burner had lit, and locked out for safety.
- On an older Glow-worm, such as a Flexicom or the first Ultracom, F3 is the fan unable to reach the speed it needs to light.
A restart is the step the Ideal and Viessmann guides give a householder for F3, though not on every model. Finding the cause behind it, on any make, is an engineer's job.
Which boilers show F3?
Ideal, Viessmann and some older Glow-worms all show F3, and the fault behind it differs from make to make. Every boiler fault code, make by make. F2, another code that means one fault on an Ideal and another on a Viessmann.
F3 on an Ideal boiler
An Ideal shows the fan fault in one of three ways, by range:
- the code F3 on the Logic Combi ESP1, the Logic Code Combi ESP1 and the Exclusive2, and on the Logic Combi from before the Combi2
- the code F 03, the same fault written with two figures, on the Logic Combi2, System2 and Heat2, and the i-mini
- the words Fan Fault, with no code, on the Logic+ Combi2, the Logic Max Combi2, the Vogue Max and the Vogue Gen2
A fan that keeps running for a while after the burner stops is normal, Ideal says, and not a fault. Ideal boiler repair, and every other Ideal code.
F3 on a Viessmann boiler
Viessmann's Vitodens 100-W of the types B1HC and B1KC show F3 when the boiler sees a flame signal before the burner has lit. The older WB1B, the 111-W B1LD, the 050-W BPJD and the 200-W B2HB show F3 for the same fault. The burner locks out, and on a B1HC the fault symbol flashes and R appears.
The newer One Base Vitodens, such as the 100-W B1HF and B1KF, show faults as numbers, and this fault shows as 68. On an older WB1B, though, 68 is a different fault, a break in the return sensor's lead. The type on the boiler's type plate tells you which applies. Viessmann boiler repair, and every other Viessmann code.
F3 on an older Glow-worm boiler
Glow-worm's own fault-finding pages for engineers list F3 on the cxi, the Flexicom cx and the first Ultracom, the cx and cxi. On those boilers, F3 is the fan unable to reach the speed it needs to light. On a CI Plus, F3 is an air fault.
Current Glow-worms, such as the Energy, the Easicom3 and the Compact, have no F3 or F.03 in their manuals. Their fan fault is F.32. Glow-worm boiler repair, and every other Glow-worm code.
Sources: Ideal's user guides and installation manuals for each range named, its Logic Combi troubleshooting page and its boiler faults FAQ, Viessmann's Vitodens instructions for each type named, and Glow-worm's trade fault-finding pages and installation manuals.
What causes F3?
The causes of F3 depend on the make, because the code means different faults. Each maker's manual sets them out for the engineer to work through, in this order:
- On an Ideal, the fan's wiring. Ideal's chart for a fan fault starts with the wiring between the fan and the main board. The engineer sees that it is secure at both ends, unworn and unbroken, and puts it right if not.
- On an Ideal, the fan or the board. With the wiring sound, the engineer checks that the mains reaches the fan. If it doesn't, the main board is replaced. If it does, the fan itself is replaced.
- On a Viessmann, the flame-sensing electrode. Viessmann's table points to the ionisation electrode, which senses the flame, and its cable, then a reset. On a 200-W B2HB, the manual adds condensate backed up inside the boiler. On a One Base boiler showing 68, the engineer closes the gas, unplugs the electrode and resets. If 68 stays, the boiler's control unit is next.
- On an older Glow-worm, the fan or the air. Glow-worm's pages name the fault, the fan too slow to light or, on a CI Plus, the air supply. Those pages give no list of checks.
Neither maker ranks the causes by how often they happen, so the list keeps the manuals' order.
Sources: Ideal's installation and servicing manuals for the Logic Combi2, the Logic Combi ESP1, the i-mini and the Vogue Max (the fan fault chart), Viessmann's installation and service instructions for the Vitodens types named, and Glow-worm's trade fault-finding pages.
Worth knowing
An Ideal Logic+, Logic Max or Vogue shows the words Fan Fault rather than F3. Read out what the screen says when you ring.
What can you safely check?
The safe checks for F3 depend on the make. Each one comes from that maker's own guide for householders. Never take the boiler's case off, and never touch anything that carries gas.
1. On an Ideal: restart once
An Ideal that shows F3 or F 03 can be restarted once with its Restart button. A Logic+ Combi2 or Logic Max Combi2 offers no Restart for Fan Fault on its screen. Its guide says to contact the installer, so ring us. If F3 comes back after the restart, stop.
2. On a Viessmann: one reset
A Viessmann's reset depends on its type:
- On a B1HC, touch R for about two seconds when the fault symbol flashes and R shows.
- On an older WB1B, wait for the fault symbol to flash. Then turn the rotary selector to the reset position for 1 to 2 seconds, and back.
- On a newer One Base Vitodens showing 68, let the burner cool, then hold the two reset buttons together for about four seconds.
Viessmann's guide warns against resetting several times in quick succession, so if F3 comes back, stop.
3. On an older Glow-worm: note the code
An older Glow-worm's user guide gives no step for F3. The Flexicom's guide lists F1, F5 and F22, and says to contact the servicing company if a fault persists. Note the code and the model on the front of the boiler, and ring us.
Sources: Ideal's user guides and its fault codes page, Viessmann's instructions for the Vitodens 100-W B1HC, the WB1B and the newer Vitodens, and Glow-worm's Flexicom cx instructions for use.
When should you stop and ring an engineer?
F3 needs an engineer once one restart hasn't cleared it. Any of these signs means ringing straight away:
- On an Ideal, F3 comes back after a restart. Ideal says it needs an engineer's visit.
- On an Ideal Logic+ or Logic Max, Fan Fault shows. The guide offers no Restart, and says to contact the installer.
- On a Viessmann, F3 comes back after a reset. The user guide says to call in the heating engineer then.
- On an older Glow-worm, F3 shows at all, as its guide gives no step for it.
- Going further would mean opening the boiler. Viessmann's guide says never to open the boiler or take its casing off.
If you smell gas, don't touch the reset. Open the gold "Smell gas?" bar on this page for the free emergency number. For anything else, ring us, as finding the cause of an F3 on any make is a job for our Gas Safe registered engineers. Boiler repair across London, every make.
The question we'll ask when you ring about F3
When you ring about F3, our first question is the boiler's make, whether Ideal, Viessmann or an older Glow-worm. The make decides which fault F3 is:
- a fan fault on an Ideal
- a flame signal before lighting on a Viessmann
- a fan too slow to light on an older Glow-worm
We'll then ask for the model, or the type on a Viessmann's type plate, and the exact code or words on the display. We'll also ask whether one restart has cleared it.
What changes the price of the fix?
What F3 costs to fix depends on the make and the cause. A loose connection at an Ideal's fan may need no new part. A fan or a main board on an Ideal is a part to fit. On a Viessmann, so is a flame-sensing electrode or its cable. The rate is agreed on the call before an engineer comes, and no work is done until you say yes. How our rates work.
Do you cover my part of London?
Yes: we fix F3 faults all over Greater London, day and night, in every borough north and south of the Thames. Pick your side of the river to see the areas.
North of the river
Every borough north of the Thames: Barnet and Enfield at the top, Hillingdon in the west, Havering in the east, and central London in between.
South of the river
Every borough south of the Thames: Richmond and Kingston in the west, Bexley in the east, and down through Croydon to Sutton and Bromley.
Questions about F3
Can I keep resetting the boiler?
No, a boiler showing F3 should be restarted once at most, after the checks above. Viessmann's guide warns against resetting several times in quick succession, because a fault that hasn't been put right can put lives at risk. On an Ideal, five restarts in 15 minutes bring up LC, or Too Many Restarts. If F3 comes back, the fault needs an engineer, so ring us.
Is F3 dangerous?
F3 is the boiler protecting itself. An Ideal stops when the fan that carries the flue gases safely out isn't running right. A Viessmann locks out when it sees a flame signal it shouldn't. Gas you can smell is a different matter, and an emergency. Don't reset the boiler, and open the gold "Smell gas?" bar on this page for the free number.
Why has F3 come back?
When F3 comes back after a restart, the cause usually hasn't gone. On an Ideal, the cause may be one of these:
- a fan wire that is loose or worn
- a fan that has failed
- a main board that isn't powering the fan
On a Viessmann, the cause may be the flame-sensing electrode or its cable. On a 200-W B2HB, condensate may have backed up inside the boiler. An engineer works through them in turn.
How much does it cost to fix F3?
The price of an F3 repair depends on the make, the cause and any part it needs. The rate is agreed with you on the call, before anyone sets off. How our rates work.
Don't know what has failed? You don't have to.Ring and say what you can see or hear. Finding the fault is our job.
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A real person answers and gives you the rate on the call. No work starts until you say yes, and repairs are guaranteed for 12 months: parts, labour and any return visit.
