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 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 |
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.
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
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.
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
Three things are often reported as faults but are described as normal operation in Faber's own manual:
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.
In a quiet room you may hear a soft hum from the transducer, fan and pump. Faber describes this as normal.
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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. |
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
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:
Procedure
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.
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
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 |
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.
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
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
