Instructions for Boiler Euroterm AURA R K 25 S – Technical and Practical Manual in PDF
With the Euroterm AURA R K 25 S condensing boiler, you achieve both heating and domestic hot water efficiently with the aid of an external boiler. The advanced condensing technology improves energy yield, requiring a drain for the condensate.
The innovative design of this boiler makes it compatible with solar systems, offering an energy alternative even when the solar system cannot provide sufficient heat.
Common Procedures
To maintain the safety, efficiency, reliability, and performance characteristics that distinguish the appliance, it is necessary to perform maintenance annually. Annual maintenance is essential for safety and continuous operation.
Effective Temperature Settings
To make the most of your Euroterm AURA R K 25 S boiler, it’s crucial to understand how to effectively adjust the temperatures. This not only optimizes home comfort but also helps prevent limescale accumulation.
Focus on Temperature Adjustment:
- Heating Temperature: Be careful to adjust the radiator temperature, not the ambient temperature.
- DHW Temperature: A lower DHW temperature reduces the risk of calcification.
Maintenance Tips
Regular maintenance of the AURA R K 25 S boiler is crucial to preserve its efficiency and safety. It is strongly advised against for inexperienced users to attempt any technical intervention on the boiler. Any doubts or anomalies in operation must be immediately reported to an expert technician. Annual maintenance, carried out by qualified technicians, is fundamental for the correct operation of the appliance.
Regarding the Use of Electric Energy
- Do not touch the appliance with wet or damp parts, or while barefoot
- Do not pull on electrical cords
- Do not expose the appliance to atmospheric agents such as rain, sun, etc., unless expressly provided for.
- In case of damage to the cord, turn off the appliance and consult exclusively professionally qualified personnel for its replacement.
Procedure in Case of Gas Leak
In the event of a suspected gas leak, it is essential to follow these instructions to ensure safety:
- Avoid operating electrical switches or devices that may create sparks.
- Open doors and windows to ventilate the area and disperse the gas.
- Immediately close the gas taps to prevent further leakage.
- Contact a qualified technician without delay for emergency intervention.
The AURA R K 25 S boiler must be used only as intended: to heat water without bringing it to a boil. Any other use is improper and dangerous. Moreover, installation and maintenance must be carried out exclusively by authorized personnel to ensure safety and regulatory compliance.
Index of Components and Spare Parts
Use this section as an index to navigate through the different components and spare parts of the AURA R K 25 S boiler. You will find clear descriptions and practical advice for each part, which will help you manage the maintenance of your appliance in the best possible way.
Boiler AURA R K 25 S Display
The display of the AURA R K 25 S boiler is information-rich and can be slightly confusing, but it displays essential parameters for operation. The Buttons:
- PLUS and MINUS Thermo: Use these buttons to increase and decrease the radiator temperature (not the ambient temperature).
- ECO/COMFORT: This button allows you to choose between ECO/COMFORT1/COMFORT2 modes for sanitary water.
- RESET: This button resets an error condition (everything but water shortage), and if held down, it enters the menu.
- SUN/SNOWFLAKE: Although the button appears large, it is a single button that switches between Summer and Winter.
Display readings:
- SUN/SNOWFLAKE: Indicates whether the boiler is in Winter or Summer mode.
- ECO/COMFORT: Indicates if the boiler is in ECO or Comfort mode.
- 1.2 bar: Shows the current pressure in the boiler.
- Drop Symbol: A drop-like symbol appears on the display, enlarging based on the flame’s power.
- Upper Temperature: It’s the Primary circuit temperature, which also rises in summer when the boiler produces DHW (Domestic Hot Water).
- Lower Temperature: It’s the current Sanitary water temperature.
DHW Production Configurations in the Boiler
The boiler offers various options for the production of domestic hot water (DHW), thanks to the integration of the COMFORT mode, available from the control panel. The modes include ECO, COMFORT1, and COMFORT2.
Details of ECO Mode
In ECO mode, the boiler disables the production of DHW. Therefore, only heating will be provided.
Details of COMFORT Mode
The COMFORT mode, in both its variants, offers preheating of DHW. COMFORT1 allows manual temperature adjustment, while COMFORT2 maintains a stable temperature at 45 degrees.
Temperature Adjustment
On the control panel of the Euroterm AURA R K 25 S condensing boiler, you can find all the operational information. You can set the temperatures for heating or hot water by pressing the + and – buttons next to their respective symbols: Faucet and Radiator. After pressing, the boiler displays the set temperature for only a few seconds.
Normally, the boiler shows the flow temperature, to be interpreted as the internal temperature of the boiler. As a result, you will see the temperature rise even in summer when the Euroterm AURA R K 25 S boiler produces hot water, while in winter it can be interpreted as the current temperature of the radiators.
Using the + and – buttons at the top for heating and at the bottom for domestic hot water, you can choose the desired temperatures for heating. We suggest:
- From 25°C to 38°C if you have underfloor heating.
- From 55°C to 65°C if you have radiators made of aluminum or steel.
- From 45°C to 60°C if you have cast iron radiators.
For domestic hot water, you can choose the temperature using the + and – buttons at the bottom. We suggest a temperature between 38 and 45°C.
The general advice for the temperature of domestic hot water is to keep it as low as possible, especially if your water supply provides very hard water (over 30°F).
Quick Solutions for Errors
- Error A01: Encountered a flame lock? No problem, just press the Reset button for an easy reset. If it persists, our support team is ready to help you.
- Error F37: Low water pressure? Simply adjust the filling tap to reach the optimal pressure of 1.5 bar. You’ll see error F37 transform into FH on the display, a sign of a perfect reset.
- FH: When you see FH on the display, your boiler is simply eliminating excess air. A brief two-minute process to always ensure the best operation.
Functioning of the Multi-Layer Aluminum Heat Exchanger
The multi-layer aluminum exchanger, a key element of the Euroterm AURA R K 25 S boiler, is distinguished by its advanced design that includes a ceramic burner and a set of fins. This structure is essential for the production of the flame and absorption of heat, crucial for the effectiveness of the heating system.
Regular maintenance of this exchanger is vital to ensure its longevity. Removing accumulations of aluminum oxide between the fins is crucial for efficient operation. For deep and effective cleaning, the use of a specific alkaline gel is recommended, followed by an energetic rinse.
It is also important not to neglect the cleaning of the condensation siphon. If ignored, it can cause an excessive increase in the temperature of the exchanger, leading to potential damages such as the breakage of the aluminum fins. If the exchanger is damaged, replacement is the only appropriate solution.
Grundfos UPS15/60 Pump Performance
Enhance the performance of your AURA R K 25 S boiler with the Grundfos UPS15/60 pump, designed for superior water circulation. Choose from three speed levels to maximize efficiency, with the third speed recommended for the best performance, except in the presence of circulation noises.
The pump, generally easy to install by a professional, may present difficulties in removing the stator from the cast iron head after a long period of use.
Technical specifications of the Grundfos UPS15/60:
- Power Supply: 2.5 μF 230V – 50Hz IP44 TF 95
- High Speed (III): 0.38 A – 85 W
- Medium Speed (II): 0.30 A – 65 W
- Low Speed (I): 0.21 A – 45 W
Suitable also as a replacement for models UPS 15-50, 15-60, 25-50, 25-60, 15-65, 25-65.
Automatic Plastic Air Purger
The plastic automatic air purger, used as an insert in the purging housing in the pump manifold, is a key component in the Euroterm AURA R K 25 S boiler. This small element plays a vital role in ensuring the efficiency of the heating system by eliminating air from the system.
Made of durable plastic, this air purger is designed to easily fit into the dedicated housing in the pump manifold. Its use is particularly recommended to prevent air accumulation in the boiler’s hydraulic circuitry, especially in systems with a lot of aluminum where this problem is more frequent after periods of inactivity (summer).
Regularly checking and replacing the air purger and the system pressure is essential for maintaining uninterrupted operation at the start of the heating season. Its functionality is crucial for the proper operation of the entire domestic heating system.
Motor Insert for Diverter Valve
The motor of the insert for the diverter valve, a crucial component in boilers, regulates the distribution of heat between the heating system and the sanitary water heating.
With a design that facilitates installation, the insert includes a motor with a connector, placed in the diverter valve for effective heat flow control.
It is important to monitor the insert to avoid issues such as motor breakdown, which can lead to uneven heat distribution, limiting heating to only one function.
Safety Systems according to the ErP Directive
The construction and installation of boilers in Europe are strictly regulated by a series of European standards, aimed at ensuring safety, energy efficiency, and reduction of environmental impact.
One of the main reference regulations is the ErP (Energy-related Products) Directive, which imposes stringent requirements in terms of energy efficiency and emissions for all energy-related products, including boilers. This directive is accompanied by specific UNI EN standards for each type of boiler, detailing the technical and safety standards to be respected.
The AURA R K 25 S boiler therefore includes:
The Safety Thermostat, located on the heating supply, intervenes by blocking the gas flow to the burner in case of overheating of the water in the primary circuit. It is essential to never deactivate this safety device.
The Flame Ionization Detector ensures safety by shutting down the boiler in case of gas absence or incomplete ignition of the main burner.
The Antifreeze Device activates the burner to maintain the water temperature above 5 °C, preventing freezing of the system.
The Hydraulic Safety Valve, set at 3 bar, protects the heating circuit. It is advisable to connect it to a siphoned drain and not use it to empty the circuit.
Boiler Errors and Anomalies AURA R K 25 S
The control board of the Euroterm AURA R K 25 S boiler is always capable of detecting anomalies. These anomalies can be blocking or non-blocking, and some may require a reset procedure. Below is a list of anomalies that may occur in the AURA R K 25 S boiler.
Boiler Errors and Anomalies for AURA R K 25 S
| Anomaly Code | Anomaly | Possible Cause | Solution |
|---|---|---|---|
| A01 | Burner Ignition Failure | Lack of gas | Check that the gas supply to the boiler is regular and that air has been eliminated from the pipes |
| Anomaly in ignition/detection electrode | Check the wiring of the electrode and that it is correctly positioned and free of encrustations | ||
| Faulty gas valve | Inspect and replace the gas valve | ||
| Insufficient network gas pressure | Check the network gas pressure | ||
| Blocked siphon | Inspect and possibly clean the siphon | ||
| A02 | Flame Signal Present with Burner Off | Anomaly in electrode | Check the wiring of the ionization electrode |
| Anomaly in board | Check the board | ||
| A03 | Over-Temperature Protection Intervention | Damaged heating sensor | Check the correct positioning and functioning of the heating sensor |
| Lack of water circulation in the system | Check the circulator | ||
| Air in the system | Vent the system | ||
| A04 | Flue Safety Intervention | Anomaly F07 generated 3 times in the last 24 hours | See anomaly F07 |
| A05 | Fan Protection Intervention | Anomaly F15 generated for 1 consecutive hour | See anomaly F15 |
| A06 | No Flame After Ignition Phase (6 times in 4 min.) | Anomaly in ionization electrode | Check the positioning of the ionization electrode and replace it if necessary |
| Unstable flame | Check the burner | ||
| Anomaly in gas valve offset | Check calibration of Offset at minimum power | ||
| Blocked air/flue duct | Clear any blockage from chimney, flue ducts and air intake and terminals | ||
| F07 | High Flue Gas Temperature | Partially blocked or insufficient chimney | Check the efficiency of the chimney, flue ducts and exit terminal |
| Flue gas sensor position | Check the correct positioning and functioning of the flue gas sensor | ||
| F10 | Anomaly in Supply Sensor 1 | Sensor damaged or wiring short-circuited | Check the wiring or replace the sensor |
| F11 | Anomaly in Return Sensor | Sensor damaged or wiring short-circuited | Check the wiring or replace the sensor |
| F12 | Sanitary Sensor Anomaly | Sensor damaged or wiring short-circuited | Check the wiring or replace the sensor |
| Interrupted wiring | Verify the presence of interruptions in the wiring and proceed with repair or replacement if necessary | ||
| F13 | Flue Gas Sensor Anomaly | Sensor damaged or wiring short-circuited | Check the wiring or replace the sensor |
| Interrupted wiring | Verify the presence of interruptions in the wiring and proceed with repair or replacement if necessary | ||
| F14 | Supply Sensor 2 Anomaly | Sensor damaged or wiring short-circuited | Check the wiring or replace the sensor |
| Interrupted wiring | Verify the presence of interruptions in the wiring and proceed with repair or replacement if necessary | ||
| F15 | Fan Anomaly | Lack of 230V power supply or interrupted tachometric signal | Check the wiring of the 3-pole and 5-pole connectors |
| Damaged fan | Check the fan | ||
| F34 | Supply Voltage Below 170V | Electrical network issues | Check the electrical system |
| F35 | Abnormal Network Frequency | Electrical network issues | Check the electrical system |
| F37 | Incorrect Water Pressure in the System | Pressure too low or water pressure switch not connected or damaged | Recharge the system or check the sensor |
| F39 | External Probe Anomaly | Damaged probe or short-circuited wiring | Check the wiring or replace the sensor |
| Probe disconnected after activating the sliding temperature | Reconnect the external probe or disable the sliding temperature | ||
| A41 | Sensor Positioning | Supply sensor detached from the pipe | Check the correct positioning and functioning of the heating sensor |
| F42 | Heating Sensor Anomaly | Damaged sensor | Replace the sensor |
Possible Improvement Works
The condensing boiler Euroterm AURA R K 25 S requires special attention to the correct installation of the flue pipe. Especially in horizontal sections, condensation can form, compromising the functionality of the fan. It is not uncommon to see installations where the flue pipe (especially if corrugated) forms a siphon, causing the boiler to produce very loud noises. It is essential to have a qualified technician ensure that the pipes are in optimal condition.
Integrating a Gas Tap with a Test Well
Not always does the meter provide a connection for instrumental tightness testing. A useful tip is to replace the gas tap under the boiler with a valve with a well equipped with an instrumental take-off, essential for the tightness test of the system. This element can be crucial in case of inspections and safety checks and certainly facilitates the maintenance of the AURA R K 25 S boiler.
In fact, during the maintenance of the appliance, it is mandatory to perform a suitable test like UNI 11137:2019 that verifies the correct tightness of the gas system.
Flushing the Heating System
Flushing the heating system is crucial to prevent clogging of the primary exchanger of the Euroterm AURA R K 25 S boiler. Over time, especially in cast iron or aluminum systems, a metallic sludge can form that can clog the narrow passages of the exchanger.
After flushing the system, it is highly recommended to install a magnetic sludge filter on the Euroterm AURA R K 25 S boiler. This filter plays an essential role in protecting the exchanger from the buildup of dirt and debris, ensuring greater efficiency and longevity of the heating system.
Additional improvements can include the installation of an advanced thermostat with relay function. This device allows for more effective management of heating hours, helping to optimize energy consumption.
Accessory Guide
Elevate the performance of your AURA R K 25 S boiler with our selection of essential accessories, we recommend:
- New Generation Programmable Thermostat: Manage ambient temperature with precision and ease, thanks to intelligent programming and remote control.
- Magnetic Filter Dirt Separator: Protects your heating system from harmful residues, ensuring greater longevity and efficiency.
Magnetic Filter for Heating
Considered the best accessory to block the entry of dust and debris from the heating system into the device.
The magnetic filter, installed on the heating return line to the boiler, is essential for maintaining system efficiency. It retains harmful elements like dust and debris, preventing boiler blockage and reducing the risk of overheating the primary exchanger. Additionally, it helps to reduce pressure on the diverter valve, thus increasing its lifespan and reducing the chances of leaks.
Polyphosphate Dosing Pump
If the hardness of the tap water exceeds 20 French degrees, we suggest equipping the Euroterm AURA R K 25 S boiler with a polyphosphate doser.
Polyphosphates, available in powder or liquid form, are mixed with the cold water entering the Euroterm AURA R K 25 S boiler, significantly reducing limescale formation. These additives are essential for maintaining efficiency and extending the lifespan of the device and must be regularly replenished.
There are several models of polyphosphate dosers, the most common ones are:
- Powder Polyphosphates
- Liquid Polyphosphates
Each type of polyphosphate requires a specific system for mixing.
Room Thermostat and Programmable Thermostat
For optimal temperature control in your home, consider installing a thermostat or programmable thermostat for your boiler.
These devices allow you to regulate and program the temperature precisely, adjusting it to your daily needs. A programmable thermostat, in particular, offers the possibility to set different programs for specific days and times, optimizing comfort and reducing energy costs.
There are various models available, including:
- Daily Programmable Thermostats
- Weekly Programmable Thermostats
- New Generation Thermostats with Remote Control
The choice of model depends on your specific needs and the configuration of your heating system.
Daily Environmental Thermostat: Regulatory Compliance and Economy
The daily environmental thermostat is the ideal solution for complying with regulations requiring at least two temperature levels within 24 hours, combining efficiency and simplicity.
This device ensures the ability to set different temperature levels throughout the day, perfectly adapting to various needs and contributing to energy savings. Its ease of use makes it suitable for all ages, including seniors.
- Flexible programming and compliance with regulations
- Easy to use for all age groups
- Affordable cost and great added value
An economical and functional option for those looking for effective home temperature control without complexity.
Weekly Programmable Thermostat
For advanced and personalized home temperature management, the weekly programmable thermostat is an excellent choice.
This device allows for setting different temperatures for various days of the week, perfectly adapting to different weekly routines. It is ideal for those who need detailed heating control, with the ability to set lower temperatures on days when the home is empty and higher when it is occupied.
Key features of the weekly programmable thermostat include:
- Flexible programming for each day of the week
- Advanced energy-saving functions
- Intuitive user interface for easy programming
A weekly programmable thermostat is perfect for those seeking a balance between comfort, convenience, and energy efficiency, providing precise control of the home climate.
Advanced New Generation Thermostats
New generation advanced thermostats offer cutting-edge technologies for optimal home climate control.
These devices stand out for their learning capability and adaptation to user habits, automatically adjusting the temperature based on daily and seasonal patterns. With features like remote control via smartphone and integration with home automation systems, they offer an unprecedented level of convenience and energy efficiency.
Salient features of these thermostats include:
- Wi-Fi connectivity and remote control
- Integration with voice assistants and smart home systems
- Learning algorithms for automatic temperature optimization
For those seeking the utmost efficiency, convenience, and personalization in home temperature control, an advanced new generation thermostat is the ideal choice.
Magnesium Anode Protection
To prevent corrosion in the Euroterm AURA R K 25 S boiler’s accumulation tank, the magnesium anode plays a key role. Its high reactivity safeguards the boiler’s metallic components from oxidation, ensuring optimal performance over time.
Scheduled regular changes of the magnesium anode are essential, based on specific usage conditions and water quality.
Issues with the Magnesium Anode
In some situations, such as in the presence of intense electrical fields:
- Rapid deterioration of the magnesium anode may occur.
- Accelerated consumption can produce excess air in the system, noticeable after periods of inactivity.
- An occasional sulfur smell may arise after long periods of boiler inactivity.
Air-related issues tend to decrease in the weeks following maintenance. Using an aluminum anode in future maintenance can offer a longer lifespan.
Aluminum Anode
The aluminum anode, used in boilers such as the Euroterm AURA R K 25 S, offers a longer lifespan compared to magnesium anodes. This flexible material allows for easy insertion and provides effective protection against corrosion.
The aluminum anode can last over 6 years, making it a cost-effective option for boiler maintenance.
Electronic Anode
The electronic anode is an advanced solution for corrosion protection in boilers like the Euroterm AURA R K 25 S. Thanks to its electronic control system, it monitors and adjusts the protective action according to the water conditions.
This type of anode requires less maintenance compared to traditional anodes and ensures more effective and long-lasting protection.
Common Questions and Answers About the Boiler
Here is a list of common questions and answers that we frequently receive about the Euroterm AURA R K 25 S boiler model. This section will help you better understand the features, functionality, and maintenance of your appliance.
Hot Water takes forever to reach the shower/bathroom !!
The delay in hot water reaching the bathroom is often caused by a buildup of dirt in the aerator or showerhead holes. This buildup can reduce water flow, consequently slowing down the flow of hot water in the pipes. Cleaning these accessories from limescale can usually restore the speed of the hot water arrival.
Additionally, if the pipes connecting the bathroom to the boiler are made of iron, they might absorb some of the water’s heat, lengthening the time for hot water to arrive. The presence of iron pipes can thus affect the timing of hot water delivery to the bathroom.
What is the difference between COMFORT 1 and COMFORT 2?
The manufacturer offers two COMFORT functions for the AURA R K 25 S boiler, activated through the ECO/COMFORT1/COMFORT2 button.
- Comfort 1: In this mode, you can adjust the domestic hot water temperature using the + and – buttons (near the faucet symbol).
- Comfort 2: In this mode, the temperature is fixed at 45°C without the possibility of adjustment.
Boiler Compatibility with Opentherm
YES: The boiler’s thermostat connections are configured for a non-powered interface, allowing connection to a Smart Thermostat or Remote Control. The possibilities offered include:
- Adjustment of domestic hot water temperature: Particularly beneficial when the AURA R K 25 S boiler is located in less accessible places like the attic or an external technical room.
- Adjustment of radiator temperature: The advanced Opentherm chronothermostat allows communication with the boiler to regulate radiator temperatures in addition to room temperature.
- Time scheduling for domestic hot water: Ideal for boilers with storage tanks, it enables optimization of boiler maintenance costs, such as gas consumption.
- Diagnostics and Error Management: With the Opentherm 2 protocol or via a specific remote control from Euroterm.
- etc…
Pressing the buttons to adjust the heating, the temperature does not change.
The button panel is sensitive to repeated presses after years of operation. Often, the malfunction of the adjustment buttons is due to the absence of a thermostat, which has led to the exclusive use of the boiler’s buttons.
In light of this, it is suggested to install a new control board to restore the correct functioning of the button panel, but also to integrate a thermostat to continue adjusting the heating from another, more reliable, and less expensive device.
