Condensing Boiler Radiant R2KA 28/20 Manual – Complete PDF Guide

With the Radiant R2KA 28/20 condensing boiler, water vapor in the exhaust gases is condensed, allowing for the recovery of latent heat. This process makes the boiler considerably more efficient compared to traditional models.

The boiler is equipped with a Storage system that offers:

• Rapid availability of hot water at the faucet.
• Superior resistance to limescale formation over time.
• Better efficiency during simultaneous use of multiple hot water outlets.

In return, this storage system requires higher energy consumption to maintain temperature and needs specific treatments to prevent legionella.

Common Procedures

To maintain the safety, efficiency, reliability, and performance characteristics that distinguish the device, it is necessary to perform maintenance annually. Annual maintenance is essential for safety and continuity of operation.

Essential Tips for Your Boiler in Winter

• Pressure Monitoring: Check your Radiant R2KA 28/20 boiler’s pressure gauge to ensure correct pressure.
• Thermostat Batteries: Replace the batteries of the room thermostat to ensure maximum efficiency.
• Heating Pressure Check: Keep the heating system pressure between 1 and 1.5 bar for effective heating.
• Qualified Assistance: Entrust the maintenance and cleaning of your Radiant R2KA 28/20 boiler to expert technicians.

Heating System Pressure Control

It’s important to check quarterly that the system pressure is maintained between 1bar and 2bar. This check is also necessary in summer, as the boiler uses radiator water to heat sanitary water. Too low a pressure can interrupt the production of heating or hot water.

Use the filling tap, located under the appliance, to adjust the pressure. Open it until the pressure reaches 1.5bar, then close it.

Boiler Temperature Management

Optimize the performance of your Radiant R2KA 28/20 boiler by correctly adjusting the temperatures. Controlling the heating and domestic hot water (DHW) through the control panel is crucial for energy efficiency and preventing limescale problems.

Details on Temperature Adjustment:

• Heating Temperature Adjustment: Refers to the radiator temperature, not the ambient temperature.
• DHW Adjustment: Set the DHW to the lowest practical temperature to avoid calcifications.

Cleaning Shower Head and Aerator Filters

We suggest regularly maintaining shower head and aerator filters, which over time can become clogged with limescale. With the progression of scaling, the aerators become difficult to remove, and there is also overheating of the hot water temperature causing the Radiant R2KA 28/20 boiler to frequently turn on and off. This is due to the wait for heat exchange between technical water and sanitary water.

Therefore, it’s good to have these accessories to replace as needed and frequently:

Boiler Safety During the Holidays

It’s crucial to take some precautions with your Radiant R2KA 28/20 boiler before leaving for the holidays to prevent accidents and problems. This also applies to the latest generation boilers.

Preventive actions:

• Close the main water tap to avoid unexpected leaks.
• Shut off the gas to increase the safety of your home.
• Turn off the heat generator to limit unnecessary energy consumption.

Once you return, reactivate the settings by following the steps in reverse. You might need to restart the heat generator to cancel the shutdown errors.

With these simple steps, you can enjoy your vacation without worries, knowing that your boiler is safe and well managed.

Intuitive User Interface

The R2KA 28/20 boiler stands out for its simple and intuitive user interface, thanks to the collaboration with NORDGAS. The {manufacturer}’s control panel is designed to be user-friendly, with clear buttons and a display that accurately reports errors, allowing for quick problem diagnosis and resolution.

Simple Error Diagnosis

Common errors such as no flame, thermal fuse interruption, or lack of water in the system are clearly reported on the display. This allows users to quickly identify the issue and take appropriate measures, such as reactivating the system or refilling the system. The boiler is also equipped with safety features like anti-freeze and preheating of sanitary water, ensuring optimal operation in all conditions.

• Error 01: No flame, which can occur if the gas tap is closed or if the meter has been changed. Press the button. In all other cases, if it does not restart, call a technician.
• Error 03: Flue side thermal fuse tripped. Press the button. If it does not restart, call a technician.
• Error 04: No water in the system. Refill the system via the black cylindrical tap under the boiler, keep an eye on the pressure gauge above the display, and close the refill tap when the pressure reaches 1.2 or 1.5 bar. The error resets itself, followed by an approximately 2-minute venting procedure. Please wait.
• Error 18: Insufficient circulation. This error may be caused by particularly dirty magnetic filters. Check the magnetic filter at the boiler inlet with a technician to restore the circulator flow rate.

Notifications

These refer not to errors but to functions currently in operation:

• F08 Anti-freeze function for heating active: If the boiler is external and reaches a very low temperature, this procedure activates to prevent the technical water from freezing. Please wait for the operation to complete.
• F33 System Venting Cycle: This usually happens during the reset of error E04. Once the {manufacturer} R2KA 28/20 boiler pressure is restored, it performs this function for about 2 minutes. Please wait for the operation to complete.
• FH Fast H20: The boiler is preparing to preheat the sanitary water. Please wait for the procedure to complete.

Noise and Consumption

Lastly, regarding noise and performance in gas and electricity consumption. {manufacturer} has designed this series of boilers to be particularly quiet, operating as silently as a whisper (about 55 decibels). The quietness is thanks to the MOPLEX muffler at the air inlet to the fan, as well as the soft panel glued to the front panel that perfectly seals the combustion chamber. The result is a very quiet boiler. Regarding gas consumption, we have a very low rate thanks to the 9 flame modulations and proportional temperature control. Electricity consumption is also low, thanks to the use of a modulating WILO circulator and a careful strategy of turning off non-essential devices in standby mode.

Boiler Usage Warnings

To ensure the safety, efficiency, and performance of the R2KA 28/20 appliance, annual maintenance is crucial. It is highly discouraged to intervene inside the boiler without adequate technical skills. In case of anomalies or malfunctions, it is important to always consult a qualified technician. Annual maintenance by specialized personnel is essential for the safety and continuous functioning 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.

Safety Actions in Case of Gas Detection

If a gas odor is detected, it is fundamental to adopt these precautionary measures:

• Do not use electrical appliances, including phones, that might generate sparks.
• Immediately open doors and windows to facilitate air exchange.
• Stop the gas supply by closing the taps.
• Immediately request the intervention of a specialized technician.

It is important to use the R2KA 28/20 boiler exclusively for the purposes for which it is designed, avoiding improper uses that can be dangerous. Ensure that any intervention on the boiler is carried out by qualified personnel to prevent accidents and maintain the warranty.

Information on Components and Spare Parts

Here is an informative resource that covers a wide range of components and spare parts for the R2KA 28/20 boiler. Each element is described in detail to help you better understand its role within the appliance and how to maintain it optimally.

Temperature Adjustment

On the control panel of the Radiant R2KA 28/20 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 Radiant R2KA 28/20 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).

Durability and Efficiency of the 20-Liter Stainless Steel Boiler

The 20-liter stainless steel boiler, an integral part of the {manufacturer} R2KA 28/20 boiler, has been developed to maximize efficiency in hot water production. Its internal coil ensures excellent heat exchange and uniform water heating.

To maintain these performances over time, regular maintenance is crucial, particularly the replacement of the sacrificial anode to prevent corrosion. Caring for this element is essential to ensure the longevity and efficiency of the boiler.

Neglecting to replace the anode could lead to premature deterioration of the boiler, with risks of leaks and inefficiencies. Therefore, it is important to adhere to the manufacturer’s maintenance recommendations and regularly monitor the condition of the anode.

Technological Innovation: The Modulating Pump for Boilers

The latest generation modulating pump, with adjustable speed from 0 to 100%, represents a qualitative leap in the efficiency of modern boilers. Managed by a sophisticated electronic system with a dedicated control connector, this pump enables optimization of energy consumption and reduction of management costs. Its ability to dynamically adapt to the system’s needs not only ensures optimal performance but is also a fundamental requirement in new installations, highlighting the importance of this technology for a more sustainable and economical future.

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 Radiant R2KA 28/20 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.

3/8 Automatic Air Purger

The 3/8 automatic air purger is a fundamental component in the Radiant R2KA 28/20 boiler to ensure the elimination of air in the heating system. This small but essential device plays a critical role in maintaining the efficiency of the heating system.

Despite its low cost, this component is vital to ensure that there is no trapped air in the radiator system, especially for aluminum ones, where the presence of air can be a frequent problem, particularly after long periods of inactivity like during the summer.

Checking the functionality and replacing the air purger is always advised to prevent circulation problems at the beginning of the heating season. Its efficiency is crucial for the proper operation of the entire domestic heating system.

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 R2KA 28/20 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.

Possible Improvement Works

The condensing boiler Radiant R2KA 28/20 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 R2KA 28/20 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 Radiant R2KA 28/20 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 Radiant R2KA 28/20 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 R2KA 28/20 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.

Installing the magnetic filter on the heating return line is a crucial step in ensuring the longevity of the boiler. This device effectively separates and retains any particles that could cause damage or inefficiencies in the device, including preventing blockage of the primary exchanger. Its presence also ensures less stress on the diverter valve, increasing its reliability and reducing the risk of malfunctions.

Choosing a Polyphosphate Doser

For hard waters exceeding 20 French degrees, we recommend the use of a polyphosphate doser for the Radiant R2KA 28/20 boiler.

These devices mix polyphosphates, either in powder or liquid form, with the incoming water, minimizing limescale formation in the Radiant R2KA 28/20 boiler. The choice of the right doser depends on the specific needs of the system and the type of water.

Polyphosphates are primarily available in two forms:

• Powder Polyphosphates
• Liquid Polyphosphates

The selection of the polyphosphate influences the type of mixing device required.

Integrated Solutions: Thermostat and Programmable Thermostat

For advanced and integrated control of the Radiant R2KA 28/20 boiler, choose a latest generation room thermostat or programmable thermostat.

These devices offer sophisticated home temperature regulation, perfectly adapting to your lifestyle and needs. With programmable thermostats, you can easily set custom schedules for each day of the week, ensuring a consistently comfortable environment and optimizing energy consumption.

Select from a variety of models, including:

• Daily Programmable Thermostats
• Weekly Programmable Thermostats
• Connected Thermostats for Remote Control

Your choice should complement the specifics of your Radiant R2KA 28/20 boiler and your home.

Daily Environmental Thermostat: Simplicity and Efficiency

For easy and intuitive home temperature control, the daily environmental thermostat is the perfect solution.

Suitable for those who prefer immediate and uncomplicated regulation, this device allows for easy temperature setting for each day, adapting to various routines. Ideal for seniors and for those who want to comply with energy efficiency regulations.

• Intuitive interface and easy programming
• Suitable for complying with energy regulations
• Cost-effective option with high practicality

An excellent choice for those seeking a balance between simplicity of use and compliance with energy regulations, without sacrificing savings.

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

The magnesium anode is the primary solution for preventing corrosion in the Radiant R2KA 28/20 boiler’s accumulation tank. This highly reactive component protects the boiler’s metal parts from oxidation, ensuring longevity and efficiency.

It is important to periodically replace the magnesium anode, depending on the water conditions and the usage of the boiler.

Possible Effects of the Magnesium Anode

Rarely, due to strong electrical influences:

• The magnesium anode may wear out very quickly.
• Due to rapid consumption, a lot of air may form and exit the tap after long periods of non-use (night).
• A slight sulfur odor may be detected after several months of boiler inactivity.

The effects related to air tend to subside shortly after the first few weeks of maintenance. However, it can be resolved at the next maintenance opportunity by preferring an aluminum anode, which also has a longer lifespan.

INFO MENU DISPLAY DATA

To view the boiler data from info menu you just have to press the INFO key. The info code will be displayed on the left side of the screen and its relative value will be displayed on the centre of the screen.
Use keys ‘ + ’ and ‘ – ’ of the heating circuit to scroll through the list of displayed data. To exit display mode press the INFO ‘ i ’ key.

Anomaly Reporting Codes R2KA 28/20

To display the last 5 anomaly reporting codes, from the most recent in chronological order, activate OFF mode using the central button and hold down the INFO button for 5 seconds. To scroll through the list of stored anomalies, use the PLUS and MINUS buttons of the heating system. To reset the anomaly history, press the RESET button. To exit the display environment, press the INFO button.

FAQ

Discover the answers to the most frequent questions about the Radiant R2KA 28/20 boiler model. This quick guide has been compiled to provide clear and direct information based on the common questions from our users.

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.

Loud Noises During Operation

If your Radiant R2KA 28/20 boiler makes loud noises during operation, first check the system pressure. Too low a pressure can be the cause. Otherwise, in this condensing boiler, it could occur due to lack of maintenance.

Indeed, the heat exchanger tends to slightly oxidize during operation and over time a large amount of dirt can accumulate in the condensate siphon. Regular maintenance is essential to reduce the risk of noises or machine shutdowns.

Opentherm Protocol Support by the Boiler

YES: The boiler is equipped with non-powered thermostatic connections, compatible with Smart Thermostats or Remote Controls. This allows the use of advanced functions such as:

• Adjusting the domestic hot water temperature: Ideal for R2KA 28/20 boilers installed in hard-to-reach areas.
• Adjusting the radiator temperature: With the Opentherm chronothermostat, it is possible to adjust the radiator temperatures directly from the boiler.
• Setting operating times for domestic hot water: A feature that helps to reduce the maintenance costs of the boiler for models with storage tanks.
• Fault Management: Using the Opentherm 2 protocol or a specific remote control from Radiant.
• 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.

Downloadable Manuals

• Technical Manual for Radiant R2KA 28/20 Boiler