Glow-worm F.32 fault codewhat it means and how to fix it
F.32 is a fan fault — the fan speed is outside what the board will accept, or the fan cannot be seen at all. Older ranges show F2 or F3. An engineer's code throughout.
Take care
Get a Gas Safe registered engineer to look at your Glow-worm F.32
We do not pass enquiries to a repair firm, so there is no form here. Find a Gas Safe registered engineer through the Gas Safe Register, and ask to see their registration card when they arrive — it is the register, not the van, that tells you they are qualified.
What does the display show?
The right answer depends on what you can see. Pick the one that matches.
Choose the option on the left that matches what your appliance is doing, and the answer for that case appears here.
F.32 with a stop
Fan speed outside tolerance — fan, Hall sensor, plug, harness or board.
Book a Gas Safe registered engineer. Do not run the boiler on repeated resets.
F32 on an Ultracom2, Betacom 24a/28a or Betacom2
Glow-worm's "incorrect air pressure — incorrect fan speed", with the flue system to be checked as well as the fan.
Book a Gas Safe registered engineer and mention if the flue terminal has been obstructed or the boiler has been noisy.
F2 or F3 on an Ultracom, Flexicom, CI or Xtrafast
F3 is "fan unable to reach ignition speed"; F2 is the fan or the air pressure switch.
Book a Gas Safe registered engineer for the older range; the fan and its pressure switch are the parts in question.
What F.32 means
Glow-worm's Energy7 and Ultimate3 manuals give F.32 a title that surprises people: "Fan frost protection function active: fan speed outside the tolerance values". The frost protection wording is the board's reason for running the fan; the fault is that the fan did not run at the speed asked.
The cause list is long and entirely electrical or mechanical — "plug on fan not correctly plugged in, multiple plug on PCB not correctly plugged in, break in cable harness, fan blocked, Hall sensor defective, electronics defective" — and the Compact manual, which simply calls it "fan fault", ends its measures with "replace the Hall sensor", the small sensor inside the fan that reports its speed. The homeowner page keeps it to "fan defective, plug or harness defective, PCB issue" and hands it to an engineer. The two-digit Ultracom2, Betacom 24a/28a and Betacom2 have F32 as "incorrect air pressure — incorrect fan speed", and add a measure the current manuals leave out: "check the entire flue system", because a fan that cannot reach speed against a blocked flue looks the same to the board as a failing fan.
Older still, the Ultracom hxi, cxi and Flexicom show F3, "fan unable to reach ignition speed", and the cxi, CI Plus and Xtrafast show F2 for a fan or air pressure switch fault; the Betacom c flashes its 70 °C temperature LED for "fault on APS". None of it is householder work.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Fan plug or harness | The first three of Glow-worm's six causes. The fan plug and the multiple plug on the PCB are both disturbed during a service, and a harness rubbed through on the fan housing breaks the speed signal. | Common |
| Fan blocked or bearings worn | "Fan blocked" in Glow-worm's list. Debris from the flue, or bearings that have stiffened after years of running, keep the fan below the speed the board asks for. A fan that has begun to whine or rattle before the code appears is telling the same story. | Common |
| Hall sensor failed | The speed sensor inside the fan. Glow-worm's Compact measure is to replace it; on most ranges it comes with the fan. The fan may be spinning perfectly and the board simply cannot see it. | Occasional |
| Flue restriction — two-digit and older ranges | The Ultracom2 and Betacom manuals say "check the entire flue system" for F32, and the older F3 is a fan that cannot reach ignition speed. A blocked or badly jointed flue loads the fan until it falls out of tolerance. | Occasional |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£100–£400
Time on site
1h 30m
A plug reseated or a harness repaired £100–£150. A fan assembly fitted £250–£400 on most ranges. A flue cleared depends entirely on what is in it.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Parts you may need
We may earn a commission if you buy a part through one of these links. It does not change what you pay, and it does not affect which parts we list.
Glow-worm fan assembly
£110–£220Authorised Glow-worm parts distributor
Price checked 28 September 2026
Glow-worm main PCB
£150–£320Authorised Glow-worm parts distributor
Price checked 28 September 2026
Own this appliance and had this code? . Nothing is published until a person has read it.
Related Glow-worm fault codes
- F.77Get it checkedF.77 on current ranges is the flue non-return flap or condensate pump not answering. On a Betacom2 or Ultracom2 it is the gas valve motor; on an Ultracom or Flexicom the optional condensate pump.Related: fan and flue
- F.25Get it checkedOn current ranges F.25 is the flue gas safety cut-out — a break in its plug or harness. On an Ultracom, Flexicom or cxi, F25 is a circulation fault. Different generations, different fault.Related: fan and flue
- F.33Get it checkedF.33 is an air supply fault on the two ranges that carry it: a Compact's flue losing too much pressure, or a Betacom3's air pressure switch not proving. Not in the Energy or Ultimate tables.Related: fan and flue
- F.28Get it checkedThree ignition attempts have failed and the boiler has locked out. Glow-worm's guides let you check the gas supply and the condensate pipe and reset three times before calling anyone.Related: same brand
- F.22Get it checkedGlow-worm's low-water-pressure shutdown, and the one code every Glow-worm user guide lets you clear yourself by topping the system up. The threshold differs by range.Related: same brand
- F.75Get it checkedGlow-worm's own documents give this code three different cause lists — pressure switch only, or sensor, pump or lack of water — and the fullest one is the Compact's eight-way diagnostic.Related: same brand
Own a Glow-worm boiler? Save it and its codes come first next time.
Related guides
Common questions about Glow-worm F.32
Why does the manual talk about frost protection?
Because the board's frost routine runs the fan and that is often when the speed check fails first, on a cold night with the boiler otherwise idle. The fault is the fan speed, not the frost function.
The fan sounds fine. Can it still be F.32?
Yes. If the Hall sensor or its wiring has failed, the board cannot see a fan that is spinning normally and reports it as out of tolerance. That is why Glow-worm list the sensor separately from the fan.
Is a blocked flue dangerous?
The boiler will not fire while F.32 stands, which is the protection. A flue that is obstructed is a matter for the engineer to inspect before the boiler is returned to service.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
- Manufacturer support portal
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.