FAQ - Frequently Asked
Questions About Heating

Photo: © Polarpx / Shutterstock.com

FAQ - Frequently Asked Questions About Heating

Topics at a glance

How often is it necessary to carry out maintenance of the heating system? Does AHI-Carrier take care of the maintenance of the heating system? What should I do if I get an error message? Here you will find answers and useful information to the most frequently asked questions about your heating system and heating system in general.

1. Heating season and temperature

Do I need to turn on the heating in the summer?

This aspect primarily relates to the relationship between tenant and landlord. The summer months are not part of the actual heating season. However, since this is not regulated by law, the question of whether heating is necessary depends on several things, including the outdoor air temperature. If the apartment or house becomes too cold and the temperature does not rise for several days, the heating will have to be turned on again. As a homeowner, you can decide for yourself when the heating should be turned on or off.

Ideally, how warm should the rooms be?

Comfortable temperature is something very individual: some people need it a little warmer, while others feel better at cooler temperatures. Nevertheless, there are some guideline values for optimal room temperature for orientation. For different parts of the house, they are as follows:

20-22 degrees Celsius in the living room
16-18 degrees Celsius in the bedroom
18 degrees Celsius in the hallway and kitchen
22 degrees Celsius in the children's room
23-24 degrees Celsius in the bathroom

When should you start heating?

There is no legally established point in time from which homeowners must provide heating, and heating periods are not defined in law at all. Nevertheless, the period from October to April has firmly established itself as the typical heating period. Thus, in many places October is considered the starting point. However, outdoor air temperature and minimum indoor temperature play a much more important role than the date.

When does the heating season end?

April is generally the most popular end to the heating season. In some areas of Germany, it is also customary to consider it mid-May. However, more important than the date are the outdoor air temperature and, most importantly, the minimum indoor temperature.

What is the optimal flow temperature?

There is no universally ideal flow temperature. The ideal flow temperature depends on many factors, such as the energy condition of the building and the heating system itself, the type and size of heating surfaces, and the type of heating system installed. Therefore, the flow temperature should match the house and the heating behavior of its residents. After all, a flow temperature that is too high leads to high heating costs. If the flow temperature is too low, the house will remain uncomfortably cool. It is best to seek advice from a Viessmann trading partner, who will not only determine the correct values for hydraulic balancing, but also help set the optimal flow temperature.

2. Maintenance and repair

Why is regular maintenance of the heating system important?

Regular maintenance and, accordingly, proper care help not only preserve the functional and operational reliability of your heating system, but also its value. The burner, boiler, and control unit should be inspected once a year. Regular inspection and maintenance will extend the service life of your heating system and ensure its safe and efficient operation. This means that energy is used as efficiently and cleanly as possible. This helps protect the environment and save on heating costs. In Germany, more than five million heating systems are either not maintained at all or are only serviced when something goes wrong, although regular inspection and maintenance are part of the responsibilities of heating and hot water system operators (paragraph 60 GEG).

How often should the heating system be maintained?

The heating system operates at full capacity for three to five months a year. Therefore, heating system maintenance should be carried out regularly. This way, you can be sure that it will work properly for a long time. However, there are no legal regulations on this matter. In practice, a twelve-month cycle has been established for most types of heating systems. Therefore, an annual inspection is recommended. In addition, you can enter into a maintenance contract. This way, you will never have to worry about heating system maintenance.

Does AHI-Carrier carry out maintenance of heating systems on behalf of the operators?

Heating system maintenance is carried out by our qualified and appropriately certified trading partners. If you want to order maintenance for your AHI-Carrier heating system, contact the installer who installed your heating system. If you currently do not have a trading partner, you can use the following button to request a quote for maintenance from certified heating contractors:

Does AHI-Carrier service the heating systems on behalf of the sales partners?

Yes, affiliated heating contractors can order services such as maintenance from the technical service of Viessmann Deutschland GmbH. Trading partners can find the relevant maintenance prices in the service price list and request maintenance tasks and contracts through the market partners portal.

When is it necessary to balance the hydraulic system?

Hydronic system balancing should be carried out if heat distribution in the house is very uneven. Without this, some radiators will remain completely cold, while others will become too warm. Hydraulic balancing is also recommended when replacing individual heating system components or when carrying out modernization. During modernization, the house's energy demand changes. In addition, hydraulic balancing may be mandatory under certain circumstances, for example, when you apply for a subsidy.

Do I need to repeat the balancing of the hydraulic system at regular intervals?

Hydronic system balancing should be carried out not as a precaution, but only if there is a need - i.e., heat is distributed very unevenly in the house and some rooms remain cold. Accordingly, the following rule applies: hydraulic balancing should only be carried out once. It needs to be repeated only if something has changed in the heating system itself, for example, replacement of individual components. Re-balancing is also recommended when implementing modernization projects. This is because energy-efficient modernization always leads to changes in energy demand. The system can be adapted to these changes through hydraulic balancing.

Can you do the hydraulic balancing yourself?

It is not recommended to carry out hydraulic balancing yourself, as it involves the most accurate optimization of the heating system, which requires all kinds of calculations. Free calculators provide only approximate values and should only serve as a guide. They do not replace hydraulic balancing performed by a heating contractor.

What is a heating system inspection and when should it be carried out?

A heating system inspection determines the optimization and savings potential of the heating system. For this, a heating contractor thoroughly examines the heating system and identifies weaknesses that reduce energy efficiency. The result is a quality energy assessment of the heating system in the form of a report. The timing of a heating system inspection is not established by law. There is also no need to conduct an inspection at regular intervals. Rather, it's about where there are opportunities for improvement. Ideally, a heating system inspection should be carried out in summer or autumn. Then there will be enough time to carry out the necessary measures before the start of the next heating season.

Why does heating need to be ventilated?

If there is air in a sealed heating system, heat is distributed with difficulty, and radiators will be warm only on one side. In addition, when the heating is turned on, sounds such as knocking or whistling are often heard. In this case, air should be released from the radiator. This will allow excess air to escape from the system.

3. Faults and damage

What do you need to remember during thunderstorms and lightning strikes?

If damage to the heating system has occurred as a result of a thunderstorm or lightning strike, all live components must be replaced. An assessment must be carried out by an expert. Neither AHI-Carrier itself nor the heating contractor can act as an expert. The expenses that will be covered depend on the insurance contract you have concluded. Depending on the specific case, the contract may be a property, building, or natural disaster insurance policy.

How to protect the heating system from lightning?

Viessmann control technology complies with standards and regulations for interference immunity. In addition, the use of lightning rods or lightning current arresters can be useful. The individual units themselves are also equipped with fine protection. In this case, interference factors are diverted directly through the protective grounding conductor.

What should be done after a storm and flood?

A thunderstorm can also lead to water damage, so special care must be taken near the heating system electronics. Under certain circumstances, such damage can even lead to a fire. Therefore, it is recommended to replace all damaged components. The damage assessment and whether expenses will be covered must be clarified with an expert. Viessmann and its trading partners cannot act as experts. You need to refer to the relevant insurance contract you have concluded.

What should I do if I get an error message?

Viessmann offers a query to the operating instructions database to help you with this. To use this feature, you will need either the serial number, which you will find on the nameplate of the heating system, or the product name, including the approximate date of purchase. If none of these options prove successful, you have the option to request instructions online.

Where can I find the serial number and year of my AHI-Carrier heating system?

The serial number can be found on the device itself. There will be a sticker with a barcode and a 16-digit number. If you cannot find this sticker, you can also contact your AHI-Carrier heating contractor. The year of manufacture can be found on the boiler nameplate or in the flue gas inspector's report. If you want to know how old your AHI-Carrier heating system is, the 16-digit number will help you - just look at the eighth digit.

If I have to bleed the air out of the radiators several times a year, does this mean that there is a malfunction?

If you have to constantly bleed air from the heating system, the system pressure may be too low. The water pressure in the heating system can be determined by the pressure gauge. The green range on the pressure gauge is the optimal water pressure. If the water pressure is too low, it may be necessary to add water.

In addition, the expansion tank may be faulty, in which case there will be negative pressure in the system and air will constantly enter it. In any case, it is best to contact an installation specialist.

Our guide describes in detail how to find a suitable heating contractor.

What should I do in case of a burner malfunction?

You may find that the burner in your boiler is faulty. Fault codes can vary depending on the model. The causes of faults also vary. Information on what to do in individual cases can be found in the operating instructions. We have compiled some general tips on the topic of malfunctions for you.

4. Function and Technology

Why can't you book a AHI-Carrier service call yourself?

AHI-Carrier works with heating contractors who provide service for all aspects of heating systems. This ensures that on-site heating contractors are familiar with local conditions.

What is the best way to regulate the heating system in the summer?

During the warm months of the year, the heating system should operate in summer mode. This is both efficient and, if your boiler provides water heating as well as domestic hot water, ensures the heating of domestic hot water. Modern models also allow you to set limit temperatures indoors and outdoors. This way, you ensure the system starts up on cool days in spring or summer, but not every cool morning.

What to do with heating during the holiday season?

For energy-saving purposes, it may make sense to turn off domestic hot water heating during summer vacations. If you have a decentralized hot water heating system, this is simple and usually pays off, especially if it's a fairly small storage tank. However, large cylinders with a capacity of 250 to 300 liters should only be completely turned off when you will be away from home for several weeks. This is because heating a cooled cylinder of this volume, among other things, consumes a lot of energy.

How to replenish water supplies for heating?

There are a number of reasons why a system owner may need to add water to a Viessmann heating system. Water pressure in the heating system that is too low may be a sign of this. Other signs include radiators that remain cold or annoying noises, possibly caused by trapped air bubbles.

There are a few things to keep in mind when it comes to properly filling the heating system. In addition to the instructions contained in the operating manual, pay special attention to water quality. Heating water must meet the requirements of the Drinking Water Ordinance [Germany] and VDI Directive 2035 to avoid damage to the system due to contamination and deposits.

The following steps must be performed:

1. Connect the heating system to the water supply using a suitable hose. A special filling valve on Viessmann heating systems ensures that water from the heating system does not enter the domestic hot water network.
2. Make sure the hose is filled to overflow so that too much air does not enter the system.
3. The valves on the fitting and at the water inlet must be fully open.
4. Heated water should be added until the system pressure rises to approximately 1.5 bar.
5. Close the valves again and bleed the air from the radiators.

If in doubt, contact one of our Viessmann trading partners.

Where does a fuel cell heating system get hydrogen from?

Hydrogen for cold combustion in a fuel cell heating system comes from natural gas. It largely consists of methane, which in turn consists of carbon and hydrogen. A reformer is needed to separate these two elements from each other - in the process, hydrogen and carbon dioxide are formed with the help of water vapor.

Why replace a 20-year-old heating system when it works just fine?

It is recommended to replace the boiler no later than after 15-20 years. This is because outdated heating equipment consumes a comparatively large amount of energy, especially when it comes to gas or oil heating systems without condensing technology. New models increase efficiency, reduce fuel consumption, and lower heating costs. Upgrading can provide additional security.

Who will explain the different functions of the heating system after installation?

The contractor installing the heating system will show you how the heating system works after the work is completed. In addition to demonstrating proper operation, they will also give you instructions on what to do in case of fault messages or what to consider when setting the heating curve.

The Lexicon of Heating Technology - Technical Terms Clear and Simple

In our Heating Technology Lexicon, you will find information and explanations of heating technology terms as well as technical terms specific to AHI-Carrier.

More information

Technologies and systems

Why does a heat pump need electricity? Is a photovoltaic system suitable for everyone? Functioning, planning and using heating and energy solutions is a complex task. If you want to learn more about common heating technologies, photovoltaics, ventilation systems and system solutions, you will find comprehensive information in these guides. Read on to find the right solution for climate and energy management. (Photo: © Irena Maslova / Shutterstock.com)

Tips & Guides

When should you start heating? How to prevent mold in the house and should you use night rollback or hydraulic balancing? These and many other questions are answered in our guides for the optimal operation of a AHI-Carrier heating system and heating in general. In this section, we also provide information on how you can reduce heating and energy costs with a few simple tricks. (Photo: © stockcreations / Shutterstock.com)

Maintenance and repair

Is your heating system not heating properly or not working at all? It's making strange noises or giving you a fault code, and you don't know what that means? Read the answers to these questions and more in our guides on all aspects of heating system maintenance and repair, and prepare your system for the next heating season. (Photo: © Marcel Derweduwen / Shutterstock.com)

Purchase Information & Tips

If you are planning to purchase a new heating system, there are various things to consider. For example, before designing a system, you need to calculate the heat load to determine how much heat energy is actually required. When choosing a system, it is also important to consider that not all heating systems are equally suitable for old and new buildings. In this section, you will find comprehensive guides with information and tips for purchasing and upgrading your heating system. (Photo: © minicase / Shutterstock.com)

Downloads - information in PDF format

Our website provides all the information about the company and the product range, which you can download in PDF format. Download here for free!

Request a Specialist's Consultation

Do you need a new heating system? But you don't know where to start? Here you can request a free expert consultation. Our experts will help you choose and plan a new heating system.

Renewable energy

Our channel partners will provide you with more favourable conditions for regular maintenance. Having a long-term agreement allows both you and our local installers to calculate costs more easily.

Instruction Manual - ViBooks

Do you receive a message about a heating system malfunction or want to know how to set the heating curve correctly? Find the right operating instructions in the ViBooks online database - in PDF format for download.

Local Trading Partners

Our regularly trained partners will not only install your new AHI-Carrier solution, but also offer maintenance and other services.

AHI-Carrier warranty

With the guarantee from AHI-Carrier, you can be sure that you are safe - in addition to the statutory warranty. All important information at a glance.
Photo: ©️sutadimage/Shutterstock.com

MENU

MENU

FAQ - Frequently Asked
Questions About Heating