Frequently Asked Questions (FAQ) about Dafi Instantaneous Water Heaters

Why should I choose an instantaneous water heater instead of a storage water heater?

An instantaneous water heater is a modern and energy-efficient solution that only operates when heating water. Unlike a storage water heater, it has no water tank, meaning it does not waste energy maintaining a constant water temperature. The average working time of an instantaneous heater is significantly shorter than that of traditional storage models, leading to real energy savings. Additionally, Dafi water heaters are compact, making them ideal for installation in small spaces where conventional storage water heaters won’t fit.

Which water heater is best for a sink or washbasin?

There are two types of units to consider:

• Over-sink water heater – ideal for those who do not need a separate tap. It is sold as a complete set with a dedicated tap and spout, making installation easy.
• Under-sink water heater – the best choice for those who want to use their own kitchen or bathroom tap. If installing under pressure, a pressure-resistant model is recommended.

Which water heater is best for a shower?

For shower installations, the best option is a pressure-resistant under-sink instantaneous water heater with a power range of 7.3 kW (230V) to 11 kW (400V). These models have an IPX5 protection rating, making them highly resistant to water splashes and humidity.

Can I install a water heater inside the shower enclosure?

Although Dafi water heaters are resistant to moisture and water splashes, they should not be installed directly inside the shower enclosure. The recommended location is just outside the shower cabin, in a safe and dry area.

What is the difference between 230V and 400V water heaters?

• 230V models are single-phase heaters designed for connection to a standard electrical outlet.
• 400V models are two-phase heaters requiring a connection to a high-power electrical circuit. These models offer higher performance and are better suited for high-demand applications.

What power rating is best for kitchen use?

For kitchen applications, such as washing dishes and hands, a 4.5 kW to 5.5 kW water heater is recommended. These models provide enough hot water for standard kitchen needs.

Can I supply hot water to two outlets at the same time?

Yes, but with some limitations:

• For occasional use (e.g., two small washbasins), it is possible to supply two outlets as long as they are within 3 meters of the heater.
• For higher demand (e.g., a shower and a kitchen sink), installing two smaller heaters instead of one powerful unit is the better solution.

Is there a risk of electric shock?

No. The only electrical component in contact with water is the heating element, which is fully insulated and encased in a protective plastic housing. There is no risk of electric shock.

Can an over-sink water heater be installed under a sink?

No. Over-sink water heaters should not be installed under sinks, especially if the tap is removed. These heaters are non-pressurized, meaning they must be used with the dedicated tap included in the set.

Can an under-sink water heater be installed above a sink?

Yes. An under-sink heater can function as an over-sink unit, provided it is connected to a dedicated tap.

Does the heater need to be mounted on a wall?

There are two installation options:

1. Without wall mounting – The heater can be connected to the water supply using flexible hoses, with no need for drilling or mounting.
2. With wall mounting – For extra stability, the heater can be attached to the wall using the included wall bracket.

Why has the hot water pressure dropped, and the temperature increased? The heater does not turn on when I open the hot water tap.

This issue is often caused by debris buildup in the water system, restricting the flow. The following steps are recommended:

• Install a water filter to remove mechanical impurities such as sand, silt, and rust particles.
• Regularly clean the tap aerator to remove blockages and improve water flow.

Does the water heater have a built-in thermostat?

No. Water temperature is controlled by adjusting the flow rate.

• Lower flow = Higher temperature
• Higher flow = Lower temperature

What is the minimum and maximum water pressure required for the heater to work?

The Dafi instantaneous water heater turns on at a minimum pressure of approximately 0.8 atm. This is the required pressure for the device to function correctly. The maximum allowable water pressure is 6 atm, meaning the heater should be connected to a plumbing system within this pressure range to avoid potential damage.

How should the electrical wires be connected to the Dafi heater?

The connection process varies depending on the voltage:

• 230V Model:

  • Yellow-green wire (PE) – Grounding
  • Blue wire (N) – Neutral
  • Brown wire (L) – Live phase

• 400V Model:

  • Yellow-green wire (PE) – Grounding
  • Two black wires – Live phases (L1 and L2)

Proper wiring is essential for safe operation and to prevent malfunctions.

Can the heater be used to preheat water from a boiler?

No. Dafi water heaters are designed exclusively for heating cold water. They do not have a thermostat to regulate water temperature, so supplying them with preheated water, such as from a boiler, can cause damage to internal components.

What should I do if my water heater malfunctions?

If your Dafi water heater experiences an issue, follow these steps:

1. Remove the device from the installation.
2. Take it to the nearest service center, along with the proof of purchase and warranty card.
3. Submit a warranty claim at the store where you purchased it or send a service request via email to serwis@formaster.com.

How do I connect a 400V heater if it has only three wires?

A 400V heater can be connected in a single-phase setup, similar to a 230V model.

• This will result in lower power output, but the device will still function properly.
• The connection requires two live phases and a grounding wire.

What could cause circuit breakers to trip?

The most common reason is overloading the electrical circuit by connecting too many devices at the same time. To avoid this issue:

• Check how many devices are running on the same circuit.
• Ensure that the total electrical load does not exceed the circuit breaker’s rating.
• More information about electrical protection requirements is available on www.dafi-water-heater.com.

What is the length of the power cord included with the heater?

• Under-sink and over-sink heaters – 1.5-meter power cord.
• Pressurized under-sink heater – Does not include a power cord. Instead, it has a removable cover with terminals for connecting wires, allowing installation as close to the wall as possible.

Do I need a separate circuit breaker for the heater?

Yes, each model requires proper electrical protection. The specific circuit breaker requirements are listed on the official website: www.dafi-water-heater.com under the "Products" section, as well as in the company’s promotional materials.

Why do higher-power models not come with a plug?

According to European Union regulations, electrical devices can be supplied with a plug only if their maximum rated current does not exceed 16A.
Since higher-power Dafi models exceed this limit, their wires do not come with a plug and must be hardwired into the electrical system.

Can a plastic spout be used with a metal faucet, and vice versa?

Yes. All faucets and spouts have the same thread diameter, so they are interchangeable regardless of material.

What is the maximum water temperature the heater can provide?

Dafi instantaneous water heaters heat water up to approximately 40-45°C (104-113°F). This temperature range is ideal for most daily household applications.

Why is the water warmer in summer and cooler in winter?

This is a normal phenomenon caused by several factors:

• Tap water entering the heater is naturally warmer in summer and colder in winter, affecting the final water temperature.
• Seasonal variations in water pressure can also influence heating efficiency.

This is not a defect but rather a normal characteristic of instantaneous water heaters operating under different seasonal conditions.

Are Dafi water heaters manufactured in China?

No. All Dafi water heaters are manufactured in Poland, in the Formaster factory in Kielce.
The entire production process – from designing and manufacturing components to assembly and packaging – takes place in Poland.
Dafi heaters are made using high-quality materials sourced from Europe, ensuring durability and reliability.

What is the average lifespan of a Dafi water heater?

The manufacturer provides a 3-year warranty for Dafi water heaters. However, based on testing and years of experience, the average lifespan of the device is 8 to 10 years, provided that it is properly maintained and used according to the guidelines.

Can the heating element and the interior of the Dafi water heater corrode?

No, Dafi water heaters are primarily made of high-quality plastic materials, which do not corrode or chemically react with water. The only metal component is the heating element, which is enclosed within a protective housing, preventing direct contact with water and eliminating the risk of corrosion. Moreover, the heating element is replaceable, allowing easy replacement if necessary.

Can I use the Dafi water heater in winter?

Yes, the Dafi heater can be used in winter, provided it is installed in a heated room. If left in an unheated environment, there is a risk that the water inside may freeze, potentially damaging the unit.

How do I protect my Dafi water heater during winter if it is in an unheated room?

To prevent water from freezing inside the heater, follow these steps:

1. Shut off the water supply to the heater.
2. Drain the remaining water from the unit by blowing out any residual liquid.
3. If extremely cold temperatures are expected, it is recommended to remove the heater and store it in a warm location.

Is it enough to just turn off the water supply if the heater will not be used for a long time?

No. Simply turning off the water supply is not sufficient, as residual water may remain inside the unit. If the heater is exposed to freezing temperatures, it is recommended to thoroughly purge it to prevent damage due to frozen water expansion.

How long is the warranty for Dafi water heaters?

The manufacturer provides a 3-year warranty on all Dafi water heaters, starting from the date of purchase.

How do I remove the knobs from the heater’s faucet?

To remove the faucet knobs, follow these steps:

1. Hold the faucet body firmly with one hand.
2. Pull the knob straight off with the other hand – avoid twisting or jerking sideways, as this may damage the mechanism.

The water heater is not heating the water – what could be the reason?

If the heater is not heating water, check the following:

1. Water pressure – if the pressure is too low, the heater may not activate.
2. Power supply – ensure that the electrical cable is properly connected and that the unit is receiving power.
3. Leaks or visible damage – inspect the heater’s housing for any water leaks or signs of wear.
4. Correct installation – make sure the heater is installed according to the manufacturer's instructions.
   If the problem persists, contact customer support for assistance.

What documents are required for a warranty claim?

To file a warranty claim for a Dafi heater, you will need:

• Proof of purchase (receipt or invoice).
• Warranty card.
• Completed warranty claim form.

What should I do if water is leaking from the faucet knob?

If water is leaking from the faucet knob, the most common cause is a worn-out valve cartridge. To fix this:

1. Check the condition of the cartridge.
2. Replace the cartridge if it is worn or damaged.

What should I do if water leaks from the connection between the faucet and the heater?

If water leaks between the faucet and the heater, follow these steps:

1. Inspect the sealing gasket – it may be worn or incorrectly installed.
2. Tighten the connection nut – if the leak persists after tightening, replace the gasket with a new one.

Why does water from the aerator flow unevenly?

If the water stream is irregular or splashes, the most likely cause is limescale buildup or debris in the aerator. To resolve this issue:

• Clean the aerator – soak it in vinegar or a descaling solution.
• Replace the aerator if it is heavily clogged and cannot be cleaned effectively.

Why does the heater initially heat the water very well but then the temperature drops?

This occurs because the standing water in the pipes before the heater is activated is naturally warmer than the fresh water that follows.

• At first, the heater uses preheated water, which makes it seem hotter.
• After a few moments, fresh, colder water enters, requiring the heater to adjust and stabilize the temperature.

How can I check the power rating of my Dafi water heater?

The power rating of a Dafi heater can be found in several places:

1. On the packaging – labeled by the manufacturer.
2. On the nameplate – located directly on the heater unit.
3. In the user manual – which includes all technical specifications.