UNIVERSAL DENTAL SOLUTIONS
F-code faults on the MELAG Vacuklav 23 B+ and 31 B+ and the Dentsply Sirona DAC Professional (the same steriliser): what each code means, what your staff can safely do, and when to call. From the authorised MELAG dealer and Dentsply Sirona service partner for Sydney, NSW and the ACT.
First rule: if a cycle aborts before the drying phase, the load is not sterile. Repack it and run it again, then look up the code.
The Dentsply Sirona DAC Professional is the MELAG Vacuklav 23 B+ built for Dentsply Sirona, and the Vacuklav 31 B+ is the shorter-chamber version of the same machine. All three use the same two-line display and the same F-codes ("Malfunction F25", for example), so this page covers all of them. Text warnings such as "Poor feed water" are included too. If you have a Vacuklav 41 B+, 43 B+ or DAC Premium with a colour touchscreen and three-digit error numbers, see the 43 B+ and DAC Premium guide instead.
What it means. The feed water conductivity is too high. "Poor feed water / replace the cartridge or module" is the warning at 40 µS/cm; you can still press S and start. "Insufficient quality of feed water / start not possible" and F25 are the stop at 65 µS/cm. F18 with "Sensor 6, Input 6" is the same reading from the conductivity sensor.
What to do now. In almost every case someone has topped the tank up with tap water. Drain the right-hand (feed) side of the tank, wipe it out, refill with demineralised or distilled water. If you have a MELAdem 40, change the mixed-bed resin cartridge. If you have a MELAdem 47, change the resin cartridge and, if due, the pre-filter and carbon filter, then empty the pressure tank to about half and give it an hour to refill. Run two or three cycles to flush the lines; the message can linger until the old water is used up.
Call us when it returns on fresh water or you need a cartridge. We carry MELAdem cartridges on the van.
What it means. The unit cannot see enough water in the feed side of the tank, or the float switch is stuck. F40 is the same check later in the cycle.
What to do now. Check the right-hand tank and refill. If it is full, lift the tank lid, remove the funnel, and move the float in the right-hand chamber up and down to free it. After filling an empty tank or changing a MELAdem cartridge there can be air in the line: acknowledge and restart until the message stops. On a MELAdem 47, check the inlet tap and the pressure-tank tap are open; a newly commissioned MELAdem 47 needs about an hour to fill.
Call us when it persists with a full tank and a free float.
What it means. F04: the "Condensate return" chamber filter is blocked, so pressure and condensate cannot leave the chamber properly. F47: the left-hand (waste) side of the tank is full, or its float is stuck. Both are the 23 B+ version of the pressure-release and drain faults.
What to do now. Let the unit cool. Unscrew the "Condensate return" filter (rear of the chamber floor) and the "Vacuum" filter (front), rinse out any pouch paper or wrap, refit. Empty the waste side of the tank completely. If F47 shows with an empty tank, free the float in the left-hand chamber. Check the unit is tilted back slightly: with the feet level, the front feet should be unscrewed about five turns on a 23 B+ and three on a 31 B+ so condensate drains to the rear.
Call us when the filters are clean and it repeats.
What it means. The sterile air filter on the back panel, which lets filtered air back in after drying, is blocked or saturated. "Notice: change the sterile filter" at the end of a cycle is the early warning.
What to do now. Look at the centre aperture of the filter on the rear panel. If it is visibly blocked, fit a new filter. If not, remove the filter and run an empty cycle; if that passes, the filter was the problem and needs replacing.
Call us when you need a filter or the empty cycle also fails.
What it means. F09 and F12: the door was not closed correctly at start, or someone tried to open it mid-cycle, or the locking pin is stiff. F01: the chamber cannot hold its vacuum, usually a dirty or damaged door seal, but also a wet or hot chamber, a flat installation angle or a blocked chamber filter.
What to do now. Press the door in lightly and slide the locking slider all the way down. If the pin is stiff, switch off, open the door and press the pin in by hand until it moves freely; clean it. Wipe the door seal and the chamber seal face with a damp lint-free cloth and look for cuts. If the seal has been replaced recently, check it is seated with the wider face towards the chamber. Let the chamber cool and dry it out before retrying.
Call us when the seal is damaged or the pin stays stiff. We carry 23 B+ and DAC Professional door seals.
What it means. The seal has stuck to the seal face, or the chamber has not finished equalising.
What to do now. Wait five to ten minutes. With the unit switched on, press the + key to unlock and pull firmly on the door. If it still will not come, switch off for five minutes and try again.
Call us when it will not release. There is an emergency-release lever but it must only be used on a cold, pressure-free unit; ring us first.
What it means. The chamber leaked more than 1.3 mbar during the vacuum test. Most often the test was run on a warm or damp chamber, which is not a real leak.
What to do now. Run the vacuum test only first thing on a cold, dry, empty chamber. Clean the door seal and flange and check the seal is seated correctly, then repeat.
Call us when it fails twice cold and clean. Do not use the unit until it is fixed.
What it means. The steam generator could not reach or hold sterilising temperature or pressure. F02 points at an overloaded chamber, a flat installation angle or a weak power supply. F34, F36 and F51 are temperature or pressure undercut during sterilisation, again usually overload or a leaking door seal.
What to do now. Halve the load. Plug the steriliser straight into its own wall socket, never a power board or a circuit shared with the compressor. Check the rearward tilt described under F04. Clean and check the door seal. If it continues on a light load, run a vacuum test.
Call us when it repeats on a light load from a good socket.
What it means. The generator's overheat protection has triggered, often because a cycle was started straight after an abort.
What to do now. Wait two minutes and restart. Keep the room under 40 °C and leave the clearances around the unit free.
Call us when it recurs on a cool unit.
What it means. The unit was switched off at the mains mid-cycle, the plug came out, or the building power failed.
What to do now. The load is not sterile; repack and rerun. Remove the sterile filter from the rear panel and run it through a Gentle program on its own, then refit it. Never switch off at the mains to stop a cycle; use Start/Stop.
Call us when the breaker or RCD keeps tripping.
What it means. F08: the internal timing check failed, usually electrical noise on the supply. F48: a parameter error.
What to do now. Switch the unit off and on and restart the program. For F08, try another socket or circuit.
Call us when F08 repeats; the supply may need a mains filter or an electrician.
What it means. The internal backup battery is low (F28, battery notice) and the clock or memory has lost data (F29, F39).
What to do now. Acknowledge, reset the date and time in the Setup menu and restart. The unit will run, but the battery needs replacing.
Call us when you see any of these: battery replacement is a technician job and we can do it at the next service.
What it means. The 23 B+ stores 40 cycle logs. When full, it asks at every start. "Output medium not ready" means a printer or MELAflash card is registered but not connected or online.
What to do now. Pressing S repeatedly clears the message and overwrites the oldest log, so output the logs first if you need them. Better: set Immediate output to Yes in the Log output menu so each cycle prints or saves automatically. If you no longer use a printer, set No output medium.
Call us when output fails. We can set up automatic logging so your records are complete for validation.
Not a fault. The batch count or 24-month interval has been reached. Press S twice to start as normal and book a service; we reset the counter.
Poor drying and high water consumption on a 23 B+ almost always come down to overloading, a flat installation angle, or something on the chamber floor blocking condensate return. Activate preheating and additional drying if your loads are heavy. A completely blank display is power: check the plug and socket, then the two device fuses at the lower front (spares are inside the door).
Yes. The DAC Professional is manufactured by MELAG for Dentsply Sirona and is mechanically and electronically the Vacuklav 23 B+. Parts, seals, filters and error codes are the same. UDS is both an authorised MELAG dealer and a Dentsply Sirona service partner, so either badge is covered.
If you fixed the cause and the next cycle passed, yes. If it aborts again or fails a vacuum test, stop and call. Record the code in your steriliser log either way.
Demineralised or distilled water meeting EN 13060 Appendix C, which in practice means under 15 µS/cm. Tap water, filtered tap water and spring water are not acceptable and will trigger F25 quickly.
Call (02) 8313 0559 with the model, serial number and the exact message on the display. A technician will tell you whether it is something you can clear or whether we need to come out.
AS 5369 validation with same-day results.
Same-day response for critical breakdowns.
Predictable per-chair monthly cost.