Frequently Asked Questions about Donner Touchless Dispensers
Common questions about Donner contactless dispensers – a comprehensive guide for every customer
Contactless soap dispensers have found a firm place in Slovak households and commercial spaces in recent years. When customers browse the Donner contactless dispensers range, they usually face a series of questions – some quite basic, others surprisingly technical. In practice, we repeatedly see the same topics: correct filling, battery life, mounting without drilling, what to do if it stops dispensing, and dozens of other small details. This article brings them all together in one place and answers them as an experienced salesperson would, someone who knows these devices inside out.
Why Donner? What distinguishes this brand from generic competitors
This question comes up quite often, even from customers who have already tried a cheaper contactless dispenser and were not satisfied. Donner is a brand designed with a focus on consistent dosage, reliable sensor, and materials resistant to moisture – which is not a given in a bathroom environment. While many cheap imports have sensors with sensitivity thresholds set only at one level, Donner calibrates it to a realistic distance of about 5–8 cm, minimizing accidental activations from air movement or reflections from shiny surfaces.
The second thing customers encounter is the tank sealing. With cheap models, after a few months, the sensor electronics can start suffering from moisture seeping in from the tank or condensation. Donner models physically separate the tank and electronics with a rubber seal, which prolongs the device's lifespan. I'm not saying they are indestructible – but they have a clear constructive approach to these problems.
Specific models currently available in the range: Donner MIST (Liquid) Bílý for liquid soaps, Donner MIST (Gel) Bílý optimized for thicker gels, and Donner MOUNT bez odkapu Černý – a model with technology preventing dripping after dispensing.
What type of soap can I use? Liquid, gel, foam – where are the limits?
This is one of the questions where people make the most mistakes, and then wonder why the dispenser stops working. The key parameter is viscosity – the density of the liquid. Each Donner model has a pump designed for a specific viscosity range, usually stated in centistokes (cSt) or described as "liquid soap" vs. "gel".
Liquid soaps (viscosity roughly 200–800 cSt) are the most universal. These include classic liquid hand soaps, antibacterial soaps, and most commonly available products from the pharmacy. The model Donner MIST (Liquid) Bílý is directly optimized for this type – the pump has a higher flow and lower pressure, which corresponds to a thinner consistency.
Gels (viscosity roughly 1 000–5 000 cSt) are thicker and require a stronger pump with higher pressure. If you were to pump gel into a dispenser designed for liquid soap, the pump would not be able to dispense the dose correctly – the result is uneven dispensing or complete failure. That is why there is Donner MIST (Gel) Bílý with a stronger motor and modified nozzle.
Foaming soaps – here you need to be careful. Foaming soap is actually a very thin liquid (sometimes thinner than water), which a special nozzle aerates into foam. Standard Donner MIST dispensers are not designed for foaming – if you were to fill them with regular liquid soap and expect foam, you won't get it. Conversely, foaming soap in a regular dispenser will not dispense properly. For foaming soaps, there are dedicated models – if you are interested in them, also check our Knowledge Center article Contactless dispenser for gel vs. liquid soap – which is better, where the differences are explored in depth.
What you should never fill: alcohol without added thickener (too thin, the sensor is not resistant to evaporation), abrasive soaps with chunks, soaps with very coarse natural particles (oat flakes, etc.) – they clog the nozzle, perfumed oils as a substitute for soap.
Battery Life – How Many Doses Do You Actually Get and When Is USB Charging Worthwhile?
This is a topic where manufacturers occasionally present optimistic numbers that don't always match reality in practice. Let's be specific. Donner models with standard AA batteries (usually 4 pcs) list a life of around 60,000–80,000 doses. What does that mean in practice?
If you use a dispenser in a family bathroom (4 members) every time you wash your hands – conservatively 10 times a day – you get roughly 6,000–8,000 days of use, i.e., 16–22 years. That sounds incredible and it really is a number under ideal conditions (new batteries, room temperature, full tank, normal viscosity). In real life, batteries lose capacity sooner due to self-discharge (typically after 2–3 years even without use) and low temperatures in an unheated bathroom.
Practical battery life of a standard set of alkaline AA batteries in a home environment: 12–24 months. With intensive commercial use (restaurant WC, office toilet), it can be 3–6 months. Here, it's worth considering models with USB charging – you don't have to worry about a stock of batteries, just occasional charging via a micro-USB or USB-C cable.
Learn more about this decision in the article Battery Power vs. USB – Which Version Suits You in this Knowledge Center.
Why batteries last shorter than they should
- Low temperature – in an unheated bathroom below 10 °C, alkaline batteries can lose up to 50 % of their capacity. Solution: lithium AA batteries, which work even at negative temperatures.
- Diluted filling – the pump has to make more rotations with each dose if the liquid is too thin. Paradoxically, a thicker gel in the correct model can be more energy-efficient.
- False sensor activations – if the dispenser is placed near a window or under the light of a strong bulb, the IR sensor can be randomly activated. Each activation consumes energy and a dose of soap.
- Battery quality – supermarket "no-name" batteries may have 30–40 % lower actual capacity than the stated value.
Installation and placement – where and how to mount the dispenser
One of the most practical questions that determines whether the dispenser will actually be used or just stand as a decoration on a shelf. Donner models are primarily designed for wall installation, either by screwing (with included anchors and screws) or using double-sided adhesive tape – suitable for tiles, glass, and laminate.
The model Donner MOUNT bez odkapu Černý has "mount" directly in the name – it is primarily intended for wall mounting and its design with a drip tray makes sense precisely when it is firmly attached to the wall and not placed on a flat surface.
Optimal installation height
This depends on who will be using the dispenser. The sensor reacts to a hand placed from below – the nozzle should therefore be at a height where you can comfortably hold your hand without bending your wrist. General recommendation:
- For adults: nozzle at a height of 90–110 cm from the floor
- For a mixed family with children: nozzle at a height of 75–85 cm (children can easily reach, adults slightly bend their wrist)
- Commercial WC: nozzle at a height of 100–115 cm – standing is comfortable for most of the adult population
Horizontal position: the dispenser should be placed at most 20–30 cm from the sink, ideally facing the dominant hand of the users. In narrow bathrooms, place it so that the sensor does not directly face the mirror – reflections from a shiny surface can cause false activations.
No-drip technology – how it works and why it's not a given
One of the questions that comes from customers who have already ordered a dispenser and are looking for the "better" model is: “Why does my soap continue to drip onto the shelf for a while after dispensing?" The answer lies in the pump construction.
Standard dispensers have a simple piston pump without a check valve. When the pump completes the stroke, a column of liquid in the hose remains under pressure and a small drop still drips. With liquid soaps that are less viscous, this effect is more pronounced – the liquid "runs" after the pressure is released.
The model Donner MOUNT bez odkapu Černý solves this problem in two ways: first, the pump has a built-in check valve that actively "sucks" the remaining liquid back into the hose after the dose is finished. Second, the nozzle has a special shape that prevents surface tension from forming a hanging drop. The result in practice: after dispensing, no drop remains on the nozzle, the surface under the dispenser remains dry.
When do you really appreciate this? When mounted on a wall above a light ceramic tile or wooden shelf. Every drop leaves a stain and over time a stain that is hard to clean. With the MOUNT model, you don't have to worry about a tray under the dispenser, a cleaning cloth, or stained tiles. Learn more about this technology and its use scenarios in the article No-drip Dispenser – When Is It Worthwhile and How It Works.
Cleaning and maintenance – how much work it is and what happens if it gets clogged
Reality check: a dispenser is not a "set and forget" machine. After a few months – the speed depends on water hardness and soap type – mineral salts (calcium and magnesium), saponified residues, and microbial biofilm start to settle in the nozzle. These are three different types of contamination and each requires a slightly different approach.
Calcium deposits from hard water
If you live in an area with hard water (most of Slovakia, especially the Záhorská and Podunajská lowlands), calcium deposits are your main enemy. The nozzle turns white and later starts to harden like stone. The solution is simple: once every 6–8 weeks, rinse the nozzle with diluted vinegar (1 part vinegar, 3 parts water) or citric acid dissolved in water. Let it sit for 10–15 minutes, then rinse. Never use stiff wire brushes – they can scratch the plastic or chrome finish of the nozzle.
Clogging of the hose with soap
If the soap in the dispenser dries out (long time without use, hot bathroom), the hose may become clogged with dried soap. Procedure: empty the tank, fill it with clean warm water and a drop of dish soap. Run 5–10 dosing cycles – the pump will flush the hose itself. Repeat with clean water until the liquid coming out is clear. This procedure is also described in the Manual for each model, but I mention it here because customers encounter it most frequently.
Microbial biofilm
Less visible, but a real issue. The inside of the tank – especially with soaps without preservatives or natural products – can host a biofilm after a long time. It manifests as a "strange smell" of the soap or a slimy surface of the tank when filling. Solution: once every 3–4 months, rinse the tank with a baking soda solution (1 teaspoon per 250 ml of water), let it sit for 30 minutes, then rinse. Do not use aggressive cleaning agents – they can damage plastic parts.
A detailed step-by-step cleaning procedure can be found in the article Cleaning and maintenance of the touchless dispenser Donner.
What to do if the dispenser stops working – diagnostics and solutions
This is by far the most common reason why customers contact support. In 90 % of cases, it is one of the following issues that the customer can resolve themselves in 5 minutes:
Dispenser does not dispense at all
First step: check the batteries. It sounds trivial, but it is the most common cause. Weak batteries may still light the LED indicator, but do not have enough power to run the pump motor. Replace with new alkaline batteries (ideally Duracell, Energizer or another quality brand) and try again.
Second step: check if the tank is filled. If it is empty, some models will refuse to dispense to prevent the pump from running dry – which could damage it.
Third step: inspect the nozzle. If it is clogged with dried soap, even the motor will not overcome it. Clean the nozzle with a damp cotton swab.
Dispenser dispenses irregularly or in small amounts
Cause #1: the soap is too thick for the given model. Try diluting it slightly with water (10–20 % volume). If that helps, you have your answer. Cause #2: there is an air bubble in the hose. Fill the tank and activate manually a few times – the pump will push the bubble out. Cause #3: weak batteries (again).
Sensor activates even without a hand approaching
False activations are mostly caused by an external source of IR radiation – direct sunlight, a strong light bulb, or reflection from a mirror. Move or reorient the dispenser. If that does not help, check if the sensor window is dirty (soap, limescale) – this can cause signal interference.
For a more comprehensive list of faults and their solutions, read the article Common faults of touchless dispensers and their solutions in this Knowledge Center.
Tank capacity – how long it really lasts and when to refill
Donner MIST models have a tank capacity of approximately 250–300 ml, with some larger versions reaching up to 500 ml. A single dose of liquid soap is typically 0.8–1.5 ml. With a 1 ml dose and a 250 ml tank, you have a supply of 250 doses. At 10 doses per day in a family of four (each person washing their hands 2.5 times per day), that is 25 days – so refilling once a month plus or minus.
In commercial spaces (restaurant, office) with higher frequency, refilling may be needed every 2–3 days with a 250 ml tank, which is operationally demanding. For commercial use, we recommend models with larger tanks or consider connecting to a reservoir (some professional models allow this). More about this parameter can be found in the article Tank capacity and dosing capacity – what to pay attention to.
Color and design – practical considerations behind the aesthetic choice
Donner offers models in white and black color variants. In addition to aesthetics, the color choice also has a practical aspect. The white version (e.g., Donner MIST Liquid Bílý) is visually cleaner and blends with most white bathroom tiles and sanitary ceramics – a classic, trouble-free choice.
The black version (Donner MOUNT bez odkapu Černý) is visually striking and suits modern bathrooms with dark elements, matte stainless steel, or industrial design. Practical difference: water droplets and limescale (white residue) are more visible on the black body, while yellowish stains from oily soaps are more visible on the white body. Both colors require regular wiping with a damp cloth.
Most frequently asked questions from customers (FAQ)
Can I fill the Donner MIST Liquid dispenser with alcohol-based disinfectant gel?
We do not recommend it for several reasons. First, pure ethyl alcohol (60–70 %) is too thin – the pump will not dispense it consistently and may lead to overdosing or dripping. Second, alcohol is aggressive to plastic components of the pump and seals – they may degrade after a few months. Third, alcohol vapors in a closed space (tank) may cause problems with electronic components. If you want to dispense disinfectants, use a model specifically designed for alcohol or a thickened disinfectant gel (viscosity similar to soap) and the MIST Gel model.
What is the difference between MIST Liquid and MIST Gel models – can they be interchanged?
Technically yes – both models are very similar in appearance. The difference is in the type of pump and the diameter of the dispensing hose. MIST Liquid has a pump with a larger stroke and less resistance – for thin liquids. MIST Gel has a pump with a smaller stroke, but a stronger motor capable of overcoming the higher resistance of thick liquid. If you fill MIST Liquid with thick gel, the pump will struggle or stop completely. If you fill MIST Gel with thin soap, you will get too large doses, the soap will spray, and battery life will be shortened. Always use the correct model for the correct type of filling.
The doser forgets to dose after a while and I have to restart it – what is happening?
This is a typical sign of weak batteries, but it can also be a overheated motor with a dense filling or an air bubble in the hose. First, replace the batteries with new ones – this will solve most cases. If the problem persists, empty the tank, fill it with warm water and run 5–10 cycles for flushing. If the doser restarts after every 3–5 doses, it may be the motor overload protection – in this case, the filling is likely too dense for the given model or the nozzle is partially clogged.
Is it possible to power the doser from the mains instead of batteries?
Directly from the mains (230 V) – no. Models operate on 4.5–6 V DC from batteries. Some Donner models have the option to charge via USB – in that case, a power bank or a USB charging adapter can be used. If your model does not have a USB port (which you can check from the product sheet or by looking at the doser), the only option is to replace the batteries. There are also universal adapters "battery to USB", which physically simulate a battery – they work, but are not an elegant solution and long-term reliability depends on the quality of the adapter.
How long does the installation take and can I do it myself without a professional?
Mounting a Donner doser on the wall can be done by an average adult in 15–30 minutes without special knowledge. You need: a drill with a tile bit (6 mm), a masonry anchor (or a drill with a masonry bit), a spirit level, a pencil, and a screwdriver. All other parts (anchors, screws, drilling template) are included in the package. If you do not want to drill, double-sided adhesive tape (e.g. 3M VHB 4910) will hold a doser up to 2 kg without problems on ceramic, glass or laminate surfaces – the condition is a dry and degreased surface. A detailed step-by-step procedure is in the article Mounting a contactless Donner doser step by step.
Warranty period and what is covered – what if the pump breaks?
The standard warranty period for Donner products sold via atria.sk is 24 months for consumers in accordance with Slovak law No. 40/1964 Coll. (Civil Code) and law No. 250/2007 Coll. on consumer protection. The warranty covers manufacturing defects – this includes faults in electronics, sensors, pump motors or mechanical defects of plastic parts that are not caused by incorrect use. The warranty does not cover: use of the wrong type of filling (e.g. thick gel in the Liquid model), mechanical damage from falling, corrosion caused by aggressive chemicals, or wear of seals due to insufficient maintenance. In case of a claim, it is necessary to present a proof of purchase and send or deliver the device according to the instructions in the warranty card.
Conclusion – practical overview before purchase
Contactless Donner dosers are well-designed products with clearly defined purpose and clear specialization of individual models. The key to satisfaction is choosing the right model for the right type of filling, installing it in the right place at the right height and giving it minimal but regular maintenance. Most problems customers encounter stem either from incorrect filling, weak batteries, or neglecting to clean the nozzle.
If you still do not know which model is right for you, read the article How to choose a contactless soap doser for your bathroom or Donner line: overview of models and their differences – both are in this Knowledge Center and cover the selection systematically according to your needs and space.
Do you have a question about this topic?
Not sure or dealing with a specific situation in your home? Write to us – we are happy to help.