Your fireplace is showing a code like CD51, flashing its lights, or has stopped producing mist altogether. This guide gives you the full picture in plain English, for both Faber e-MatriX and the Dimplex Opti-myst cassettes: what the code means, what you can fix yourself in five minutes, which spare part solves it, and when to call a technician. If your fire runs from a water tank rather than a mains connection, the installation is covered in our separate water pump kit guide.
Find your model
Faber or Dimplex - and which one?
Faber and Dimplex are part of the same group, and from summer 2026 the fireplaces are being brought together under the Dimplex name. The technology is unchanged, and so are your warranty and your spare parts. If your fireplace says Faber on it, it hasn't been discontinued - it simply goes by a different name from now on.
The two families look alike but report faults in completely different ways. Find yours before reading on:
| Your fireplace | How it reports faults | Read this section |
|---|---|---|
|
Faber e-MatriX linear, mood, 800/1600 ST |
A code such as CD51 on the remote control display and in the Faber ITC app | CD codes |
|
Dimplex Opti-myst cassette Cassette 400, 500, 600, 1000 |
A beep and a flash pattern on the fireplace itself. Newer RGB models also show a code on the remote | Cassette codes |
Is your cassette Retail or Projects?
This determines which faults are even possible. Retail runs from a water bottle you fill yourself. Projects is plumbed into the mains. No bottle in the fireplace means you have a Projects model.
Does your Cassette 400 have lamps or LEDs?
The Cassette 400 exists in two generations. The older one uses halogen lamps, the newer one LEDs. It makes all the difference when the flame turns grey: on the halogen model that's a blown lamp, on the LED model it's electronics. Lift off the fuel bed and look - lamps are clearly visible in their holders.
Start here
Four things that fix most faults
Most e-MatriX enquiries we receive are not about a faulty fireplace. They are about limescale, a closed valve or an empty tank. Check these four before working through the code list.
- Is the main switch set to I? Switch A sits in the control box behind the service hatch and controls all power to the fireplace. Set to 0, nothing happens.
- Is there water? On mains supply: is the stopcock fully open? On pump supply: is there water in the tank, and is the valve between tank and pump box open?
- Is the filter blocked with limescale? The in-line filter clogs over time, especially in hard water areas. It is the single most common cause of CD51.
- Have you waited 15 seconds? The lights come on immediately, but the flame effect takes around 15 seconds to appear. That is normal.
Use filtered or decalcified water only. Limescale is the number one cause of faults on the transducers, the solenoid valve and the float - and limescale damage is not covered by the warranty. In a hard water area, an in-line water filter will save you both cleaning and spare parts.
Normal operation
These are not faults
Three things are often reported as faults but are described as normal operation in Faber's own manual:
Delay on start-up
The main lights come on straight away, but the mist has to build up first. e-MatriX around 15 seconds, Cassette 400/600 around 30 seconds, Cassette 500/1000 around 45 seconds.
A faint sound
In a quiet room you may hear a soft hum from the transducer, fan and pump. Faber describes this as normal.
Low flame on start-up
The fire always starts on the lowest flame setting. Turn it up afterwards. The flame also looks more realistic below maximum than at full.
The remote control is the room sensor. Left on the sofa or close to the fire, it reads the wrong temperature. Place it in the wall holder at around 1.5 m height, away from the fire's radiant heat - and not in a corner, by a window or door, or above a radiator.
Faber e-MatriX
What does the CD code on the display mean?
When the fire stops, the remote control display shows CD followed by a number. In the Faber ITC-V2 app you'll find the same code under the exclamation mark !. The colour on the left edge tells you which system the fault sits in: blue = water, purple = electronics, red = heat and connectivity.
The sump did not fill within 45 seconds. The fire shuts down to protect the transducers, which must never run dry.
What you can do
- Check that the stopcock to the fireplace is fully open.
- Inspect the triangular in-line filter on the pipe for limescale and debris - clean or replace it.
- On pump supply: is the tank empty, or is the valve between tank and pump box closed?
- Reset afterwards: select CD51 and hold ✔ for 3 seconds.
The level sensor in the sump is registering too much water. Usually because the solenoid valve is not closing fully - normally due to limescale on the valve seat.
What you can do
- Switch off at main switch A and shut off the water.
- Check whether water is standing in the sump or in the bottom of the casing.
- If the code persists after descaling, the solenoid valve needs checking by a technician.
The control box is receiving illogical signals from the level sensor - reporting "full" and "empty" at the same time, for instance. Almost always because the float is stuck in limescale.
What you can do
- Descale the sump and gently free the float so it can move up and down freely.
- Switch to filtered water from now on, or the fault will return.
The absorption valve or the drip tray in the base has detected moisture. The fire shuts down deliberately to prevent water damage and short circuits.
What you can do
- Switch off both power and water immediately.
- Check every pipe joint, clip and fitting for leaks - including on the pump kit if you have one.
- Dry the base completely and find the cause before restarting.
The small sponge in the absorption valve - the Sponge Pill - has become wet, expanded and shut off the water supply. It is a one-shot safety device: it does not reset itself, and it cannot be reused once triggered.
What you can do
- Find and fix the leak first. Otherwise the new pill will trip straight away.
- Replace the Sponge Pill: remove the orange nozzle, lift out the water vessel, and fit the new pill where the water supply enters the fireplace.
The ultrasonic transducer - the disc that actually creates the mist - is not responding. Transducers are wear parts with a limited service life, particularly if the fire has been run on hard water.
What you can do
- Check that the connector is properly seated.
- Look for moisture or white/green deposits on the connector pins.
- If the disc is scaled up or worn, the transducer needs replacing.
The same fault as CD20, just on one of the other transducers. Wide models such as the e-MatriX 1600 have up to five transducers spread along the sump - which is why the flame can disappear at one end while the rest keeps running.
What you can do
- Count along to the right transducer: numbering follows the sump from one end.
- Same approach as CD20 - connector, moisture, limescale, and replacement if worn.
The top fan that lifts the mist up into the fireplace opening is not turning. Without it the mist stays in the sump and the "flame" looks flat or disappears entirely.
What you can do
- Check for dust, hair or objects blocking the blades.
- Carefully vacuum the ventilation openings.
- If it still doesn't run, the motor needs replacing.
The controller has lost contact with the RGB board in the top or the base (Top Light / Bottom Light). That lighting is what gives the flame its colour - lose it, and the mist turns grey.
What you can do
- Check the connection between the ITC control box and the LED strips.
- If the fire sits in a recess, a connector may have been pulled loose during installation.
The radio link between remote and receiver has dropped. Because the remote also acts as the room sensor, the thermostat can stop working even though the fire is otherwise running.
What you can do
- Replace the batteries - 2 × AA 1.5 V alkaline. The battery cover unscrews on the back.
- Re-pair like this: main switch A to I → press the pairing button (no. 2) in the control box → press O and the heat button on the remote at the same time until the LED flashes blue. Release. A green flash means the connection is established.
The Faber ITC-V2 app cannot reach the control box. The fire may well keep running - you just can't control it from your phone.
What you can do
- Restart the control box at switch A: off (0), wait 60 seconds, on (I).
- Close the app completely and reopen it. Check that Bluetooth is enabled on your phone.
- If the fire is completely dead - no light, no sound - suspect the power supply or a fuse.
Applies to models with a heater module. The cut-out shuts off the heat when the fire cannot shed its own heat.
What you can do
- Remove anything covering the fire or its ventilation openings - curtains, furniture, ornaments, clothing.
- Let the fire cool for 10-15 minutes before restarting.
- If it keeps happening, the installation is too tight. It needs more ventilation area.
The heater module's fan is not rotating correctly in operation. The flame effect may keep running - it is only the heating function that fails.
What you can do
- Check for obstructions and dust at the heat outlet.
- If the fan runs unevenly, is noisy or doesn't run at all, it needs replacing by a technician.
No code matches your search. Try the number on its own - for example 51 - or send us a message by email.
Dimplex Opti-myst cassettes
Flashes and codes on the Cassette 400, 500, 600 and 1000
The cassettes don't use CD codes. They give a beep and flash their lights in fixed patterns, with an eight-second pause in between. Count the flashes and find them here. On a Cassette 1000, only the side with the fault will flash.
| Flashes | Meaning | What you can do |
|---|---|---|
| 1 flash | Too much water in the sump | Retail: check that the water bottle valve is sealing. Projects: the solenoid valve probably isn't closing fully - flush it through. Empty the sump manually and restart. |
| 2 flashes | Not enough water | Retail: refill the water bottle. Projects: check the stopcock is open and the pressure is sufficient. The sump must reach above minimum level within 20 seconds. |
| 3 flashes | Float or sensor fault | The floats in the sump are sending a signal the controller can't read. Check they are seated properly, move freely, and aren't stuck with limescale. Clean the sump. |
| 4 flashes | Filling too slow | The water didn't reach maximum within 90 seconds. Check the in-line filter on the water pipe for limescale. If needed, pour a little water directly into the sump before restarting. |
Codes on newer RGB models
The latest Cassette 500 and 1000 ship as multicolour and also show a code on the remote control:
| Code | Meaning | What you can do |
|---|---|---|
| Error 1 | No water, running dry | The tank is empty or the transducer is running dry. Refill the tank or check the supply line. |
| Error 20 | Transducer 1 faulty or disconnected | Check the connector is seated. If the disc is scaled up or worn out, the transducer needs replacing. |
| Error 21-24 | Transducers 2 to 4 faulty | Applies to the Cassette 1000, which has several transducers. The flame typically disappears at one end. |
| Error 51 | Water filling timeout | The valve stayed open without the water reaching level. Check the supply and the filter. |
| Error 58 | Safety valve tripped | The absorption pad in the base has become wet and shut off the water. The pad must be replaced and the base dried. |
The Cassette 500 and 1000 have a leak prevention valve with a pad that absorbs water and shuts off the supply. It can be triggered if the fireplace is moved or tilted without being drained first - during a house move or flooring work, for instance. If the fireplace won't fill after being shifted, a tripped leak valve is the first thing to check. The pad can't be dried and reused, it has to be replaced. A spare pad was supplied with the product from the factory - check the box.
On the older model with halogen lamps, a grey or colourless flame is almost always a blown lamp. Let the fireplace cool for 20 minutes before changing it. On the LED model, the same symptom points to the light board or driver - and that needs a technician.
Hardware signals
e-MatriX: when the display is dead, read the flashes
If the app and remote are unresponsive on an e-MatriX, you can still read the fault directly on the control box. The red status LED flashes in fixed patterns. Count the flashes and find them here:
No mist or low water level - and the fire is not refilling automatically. Check water supply and tank.
Water leak detected in the base of the casing. Switch off power and water now. Equivalent to CD57.
Water is taking too long to flow in. Same cause as CD51: closed valve, empty tank or a clogged filter.
Water level in the sump is critically high. Equivalent to CD52 - the solenoid valve is probably not sealing.
Procedure
How to reset an error code
There are two methods. Always try the soft reset first - and remember that a reset only clears the message. If the cause is still there, the code will return within minutes.
Soft reset - via app or remote control
- Find the code on the remote control display or under ! in the Faber ITC-V2 app.
- Select the code and hold ✔ (OK) for 3 seconds.
- Wait. The system attempts to restart itself. The flame returns after around 15 seconds if the fault has cleared.
Hard reset - power cycle
- Switch off at main switch A in the control box behind the service hatch. Set it to 0.
- Wait 60 seconds. The electronics need to discharge fully, or the controller will remember the fault.
- Switch back on at I and start the fire as normal.
Resetting a Dimplex cassette
The cassettes have no code button. You reset them with a hard restart: switch off at the mains switch, wait at least 10-15 seconds, then switch back on. For the slow-fill fault (four flashes), Dimplex recommends leaving it to rest for 30 seconds.
For CD57, CD58 and Error 58 - water leak and tripped safety valve - find the cause before you reset. Repeated resets with a leaking pipe can cause water damage to flooring and electronics. The same applies to CD52 and to one flash on a cassette: the fire already has too much water in it.
Spare parts
Which part solves your problem?
Below are Faber's original spare parts arranged by symptom, so you can go straight from an error code to the correct part number. Quote the number when you contact us and we can come back with price, availability and lead time.
These are Faber's own part numbers. Several parts exist in model variants - type 1 versus type 1.1 (re-engineered), and RGB versus standard lighting, for example. Send us the model name and serial number from the rating plate by email and we'll confirm the part number and quote you before anything is ordered. Parts shown as links can be added to the basket directly.
| Symptom / code | Part you need | Faber part no. |
|---|---|---|
| Water takes too long to flow in CD51 |
In-line water filter Mesh filter Solenoid valve |
06023397 06023605 06023371 |
| Water level too high CD52 |
Solenoid valve Max reed switch |
06023371 06023387 |
| Float reading incorrectly CD53 |
Float magnet Float stopper Min/overflow reed switch Sump assembly, incl. float magnets |
06023366 X-9602550100RP 06023388 X-SP01/19138/0 |
| Leak protection tripped CD57 · CD58 |
Sponge for absorption valve Absorption valve complete, incl. sponge |
06023611 X-SP03/23608/0 |
| No mist, or mist gone at one end CD20-CD24 |
Transducer with cone Transducer without cone (older models) |
06023368 205698 |
| Uneven or scattered mist | Nozzle assembly Mist baffle at the nozzle (orange) Engine air filter |
06023369 06023599 X-SP01/67007/0 |
| Mist doesn't rise CD30 |
Extractor fan (Fergas 51032) DC extractor fan (Fergas 51993) Extractor fan assembly, complete |
06023818 06023681 20901501 |
| Flame loses its colour CD35 |
LED driver (yellow) LED strip yellow, 15 × 1 W LED strip RGB + yellow, 13 × 1 W LED power supply 5V DC |
06023377 X-03/23778/0 100000294 20615700 / 20614700 |
| Remote control unresponsive CD10 |
Remote control with display, 6 button Remote control, 6 button Bluetooth receiver |
06023800 06023604 300003013 |
| Fire dead or offline CD12 |
Headless module Main PCB MKIII PSU 24V DC On/off switch |
X-SP03/23619/0 06023868 06023379 06023400 |
| Overheating and heater faults CD80 · CD81 |
NTC thermostat sensor PCB heat relay Heat element 200 W Ventilation grid set (2 pcs) |
06023679 06023799 06023619 A9296400 |
| No crackling sound | Speaker | 06023375 |
| New water connection or leaking pipe | Water connection set (ball valve + fittings) Adapter kit ½" + 2 m tubing Water tube ¼" per metre Safety clip ¼" |
06023373 06023594 06023606 06023885 |
| Pump operation without mains water | Pump accessory kit (tank not included) Connection wire (A), 2-way, 2 m |
400001562 06023876 |
Spare parts for Dimplex cassettes
The cassettes use their own numbering system, but many of the parts are physically identical to those in an e-MatriX - the leak prevention sponge, the transducers, the reed switches, the filters and the fan all carry over. Email us with your model, serial number and what the fireplace is doing, and we'll identify the right number and come back with price and lead time.
Two things worth knowing in advance. The transducers are not the same across the range, so the part number depends on whether you have a 400/600, a 500/1000 or an RGB model. And for the oldest Cassette 400 with halogen lamps, spares are all but exhausted - only the lamp holder and remote remain. If that's your model, get in touch early so we can find a solution rather than leaving you waiting for a part that no longer exists.
Ventilation grilles - the fix for CD80
If the thermal cut-out keeps tripping, the installation lacks ventilation area. The grilles below are specified for e-MatriX and come in black and white. Choose the size for your model:
| Fits | Size | Ventilation area | Black / white |
|---|---|---|---|
| e-MatriX 800 | 80 × 6.5 cm | 210 cm² | Black · White |
| e-MatriX 800 | 80 × 7.6 cm | 210 cm² | Black · White |
| e-MatriX 800 | 50 × 10 cm | 214 cm² | Black · White |
| e-MatriX 800 | 25 × 20.5 cm | 210 cm² | Black · White |
| e-MatriX 1050 and 1300 | 100 × 9 cm | 450 cm² | Black · White |
| e-MatriX 1050 and 1300 | 100 × 11 cm | 420 cm² | Black · White |
Prevention
Maintenance that keeps the error codes away
Both the e-MatriX and the cassettes are water appliances. Almost every fault we see traces back to limescale or algae. Five minutes now and again saves you a service visit.
If the fireplace will stand unused for more than a week, drain the sump and water tank and dry the sump. And never move a cassette - not even a short distance - without draining it first. That trips the leak prevention valve.
| How often | What |
|---|---|
| Every 1-2 weeks | Clean the water tank, sump, sump lid, tank cap and air filters. More often in hard water areas. |
| Every 4 weeks | Descale the sump and check that the float moves freely. If the fire runs from a water tank, the tank needs cleaning too - see the pump guide. |
| As needed | Remove the glass as described in the installation instructions and clean it with ordinary glass cleaner. Never abrasives or aggressive products. |
All visible surfaces - including the glass - can exceed 100 °C. Let the fire cool completely before starting work. The appliance must be connected to an earthed socket, never an extension lead, multi-plug adapter or timer.
Frequently asked
Common questions
What does CD51 mean on my Faber e-MatriX?
CD51 means the sump did not fill within 45 seconds. The three most common causes are a closed stopcock, a limescaled in-line filter on the pipe, or an empty water tank if the fire runs on a pump. You reset the code by selecting it in the app or on the remote control and holding ✔ for 3 seconds.
Can I use ordinary tap water in an e-MatriX?
No. Faber specifies filtered or decalcified water. Tap water contains limescale, which builds up on the ultrasonic transducers, the float and the solenoid valve and eventually triggers error codes CD20, CD52 and CD53. Limescale damage is not a warranty matter.
How much water does an e-MatriX use per hour?
An e-MatriX mood and an e-MatriX 800/1600 ST use approximately 200 ml of water per hour. An e-MatriX linear uses approximately 400 ml per hour. With a 10-litre tank that equates to roughly 50 and 25 hours of running time respectively.
What is a Sponge Pill and when does it need replacing?
The Sponge Pill is a small sponge fitted where the water supply enters the fireplace. When it gets wet it expands and shuts off the water supply so the appliance cannot flood. It is a single-use part: once triggered - typically alongside error code CD57 or CD58 - it must be replaced with a new one.
Why does it take 15 seconds before the flame appears?
That is normal operation. The main lights come on immediately, while the ultrasonic transducers need to build up mist before the flame effect becomes visible. Faber states approximately 15 seconds in the user manual.
My fireplace is flashing twice. What does that mean?
On a Dimplex Opti-myst cassette, two flashes mean there is not enough water. If you have a Retail model with a water bottle, the bottle needs refilling. If the fireplace is plumbed in, check that the stopcock is open and that water pressure is sufficient to fill the sump above minimum level within 20 seconds.
Why is my Faber fireplace suddenly called Dimplex?
Faber and Dimplex belong to the same group, and from summer 2026 the fireplaces are being brought together under the Dimplex name. It is purely a change of name. The technology, the spare parts and the warranty on your fireplace are unchanged, and we service Faber models exactly as before.
How long does a transducer last?
A transducer disc typically lasts between 1,000 and 2,000 operating hours. Used four hours a day, that works out at roughly one and a half to two years. Filtered or decalcified water extends that noticeably, while ordinary tap water shortens it.
How much does a spare part cost?
Prices depend on the model, the part variant and current availability, so we quote each request individually. Send us the part number along with your model name and serial number by email and we'll come back with price and lead time.
Can I replace a transducer myself?
Transducers are wear parts and can be replaced, but the work takes place in a housing where water and electricity sit close together. We recommend that replacement, and any other work on the sump and electronics, is carried out by a qualified technician. Send us your model and serial number and we'll identify the correct part for your appliance.
Still stuck?
We have been selling and servicing water vapour fireplaces since 2012 and know the e-MatriX range inside out. If you have a code that isn't on this list - or you're unsure which spare part suits your particular model - send us an email. With the model name and serial number from the rating plate to hand, we can come straight back to you with the right part, a price and a lead time.
Email us at info@bioethanol-fireplace.co.uk
This guide is based on Faber's user manual for e-MatriX linear, e-MatriX mood and e-MatriX 800/1600 ST (doc. 40012119-2240) and the installation instructions for the Pump Accessory Kit (08/54487/0, issue 2). Error codes may vary between production years and software versions. If in doubt, contact us before dismantling anything. Work on the water and electrical installation must be carried out by a qualified installer.
