Step-by-step installation of Avansa circulation pump
Step-by-step installation of the Avansa circulation pump – complete guide for plumbers and DIY enthusiasts
Replacing or installing an Avansa circulation pump is a task that an experienced plumber can complete in an hour. However, a careful DIY enthusiast who reads this guide thoroughly and prepares all the tools and parts before starting the installation can also manage it. In practice, we often see that the most common problems after installation – noise, insufficient flow, air in the system – do not come from a faulty pump, but from installation details that are easily overlooked. This article discusses all of them in detail.
We will focus on specific models from the Avansa range – from the compact AVANSA 15-6/130 through standard models up to the electronic AVANSA AUTO 25-4/180 E. The installation procedure is very similar for the entire range, with differences in dimensions, thread sizes and settings – all of which are described directly in the text.
What to prepare before installation – tools, parts and safety
Before draining the system or working with electricity, make a list and check it off. From my own experience, I know that running out of a sealing ring during installation, when the boiler is already running and the system is partially drained, is unnecessary stress.
Tools
- Adjustable wrench or a pair of flat wrenches (size 30–46 mm depending on the thread size)
- Flax fiber + sealing compound (Loctite 55, Teflon tape, or flax gasket)
- Bucket or a draining container to catch water
- Voltage tester or multimeter
- Flat screwdriver and crosshead screwdriver
- Level (at least 30 cm)
- Cloth and sealing compound cleaner
- Inspection mirror for checking the thread from below (optional, but handy)
Parts and consumables
- New Avansa circulation pump – the correct model and spacing (130 mm or 180 mm)
- Union (ideal with ball valves on both sides, if not already installed)
- Gaskets for the union (usually included, but double-check)
- Closing valves, if not already available
- Pressure gauge hose for bleeding (optional)
Safety first
Before making any changes to the heating system, disconnect the electrical supply to the boiler and pump. Confirm this with a voltage tester – simply turning off the switch is not enough. If you are replacing the pump during the heating season, allow the system to cool down to less than 40 °C. Working with hot heating water is a serious risk of burns.
Where exactly to install the pump – position in the circuit
The Avansa circulation pump is installed on the return pipe in the vast majority of installations – that is, on the side where the cooled water returns to the boiler. The temperature on the return is lower (typically 55–65 °C compared to 70–80 °C on the supply), which prolongs the life of the pump's seals and bearings.
The direction of water flow through the pump is indicated by an arrow on the pump body – this arrow must match the actual flow direction in the system. If installed in the opposite direction, the pump will still function, but its performance will drop significantly and mechanical damage is possible.
Horizontal or vertical installation?
Avansa pumps are designed for horizontal installation of the rotor axis – this is the standard case when the pipe runs horizontally and the pump is horizontally inserted into it. The terminal box (electrical connection) must always be at the top or at least in a side position, never pointing downward. The reason is simple: if the terminal box is pointing downward, condensation or water leakage can reach the electrical components.
Certain Avansa models allow for vertical installation (vertical pipe) – in this case, it is essential that the direction of water flow matches the orientation of the arrow and that the motor and terminal box are still "on top" in relation to the rotor axis. Always check the technical specifications of the specific model to confirm which positions are allowed.
Draining the system and removing the old pump
If you are replacing an existing pump, the first step is to close the ball valves (shut-off valves) on both sides of the pump. Most modern installations have these valves – if not, you will have to drain the entire system, which is significantly more laborious. Therefore, if you are installing a new system, always design it with shut-off valves near the pump. This will save you hours of work with every future replacement.
Draining the section with the pump (if the valves are present):
- Close the valve on the inlet side (input to the pump)
- Close the valve on the outlet side
- Place a bucket under the pump
- Slowly loosen the air vent screw on the pump (usually located on the front motor cover) – the remaining water will drain from the pump body
- Unscrew the shut-off valve on the inlet side, then on the outlet side
The old pump is pulled out sideways. Check the condition of the threads in the pipe – corrosion or damaged threads must be repaired before installing the new pump. Minor contamination with metal particles or magnetite on the pipe indicates that the system is dirty and it is worth flushing it before installing the new pump.
Installation of the new Avansa pump – step by step
Step 1: Check the pump before installation
Unpack the pump and check that it is not mechanically damaged. Check the label – power, voltage (230 V / 50 Hz), IP rating, maximum medium temperature. For most family homes, models with a 130 mm pitch are used (e.g., AVANSA 15-6/130 or AVANSA 25-6/130) or 180 mm (e.g., AVANSA 25-4/180). More on how to interpret these numerical designations can be found in the topic What do the numbers in the name of the Avansa pump mean – power, head and pitch.
Turn the pump rotor by hand (the screw on the front motor cover) – it should rotate freely, without jamming. If the new pump has been stored for a long time, the rotor may be stuck. A few drops of water through the air vent screw and gentle turning with a screwdriver will help.
Step 2: Prepare the thread sealing
The threaded connection is where leaks begin if the sealing is neglected. For G 1" threads (model AVANSA 15-6/130) or G 6/4" (most other models in the range), use a combination of hemp fiber and sealing tape, or special sealing compound for heating (e.g. Loctite 55 or Tangit). Teflon tape is less suitable for heating systems – at higher temperatures it loses elasticity.
Wind the sealing material always in the direction of the thread (clockwise when viewed from the front of the thread), otherwise it will unwind during tightening. The wound fiber should have 6–8 layers and be evenly distributed along the entire length of the thread, not just at the end.
Step 3: Check the flow direction
This is a critical detail that is surprisingly often overlooked. On the pump body (or on the packaging, if the body is not yet mounted), find the arrow indicating the flow direction. This arrow must point from the medium inlet (return from the system) towards the boiler. If you are unsure about the flow direction in the pipe, use a temperature probe or simply check which side of the pipe is warmer before the boiler.
Step 4: Mount the pump into the shut-off valves
Insert the pump between the shut-off valves. Ensure that the pump is aligned with the pipe – misalignment causes vibrations and accelerates bearing wear. Use a spirit level: the pump axis must be horizontal, the terminal box must be on top (or at most slightly to the side, not below the axis).
Start tightening the shut-off valves by hand, then with a wrench – tighten evenly on both sides, not first one side to the end and then the other. The recommended tightening torque varies according to the thread size, but for G 1" it is typically 50–60 Nm and for G 6/4" around 80–100 Nm. Without a torque wrench, a simple rule applies: tighten firmly, but not so much that the sealing or the shut-off valve cracks or deforms.
Step 5: Electrical connection
Before any work on the electrical part, check again (with a voltage tester!) that the power supply is disconnected. Avansa pumps are powered from a single-phase network 230 V / 50 Hz. The terminal box is opened by unscrewing the cover (usually 2–4 screws). Inside you will find terminals marked L (phase), N (neutral) and PE (grounding – earth terminal).
Route the cable through the cable gland (PG connector), which is part of the terminal box cover. Tightening the cable gland prevents mechanical stress on the terminals and prevents moisture from entering. The cross-section of the cable should be at least 0.75 mm² (sufficient for typical pumps up to 100 W), but in practice 1.5 mm² is often used for mechanical durability.
In the electronic model AVANSA AUTO 25-4/180 E, the terminal box may be supplemented with terminals for an external signal or communication (depending on the specific version). The procedure for connecting the basic power supply is the same, connect the additional terminals according to the attached wiring diagram.
Step 6: Filling the system and bleeding air
After electrical connection, close the terminal box and open the ball valves – first the inlet (return), then the outlet (towards the boiler). The system will start to fill. At this stage, bleeding air is crucial.
Avansa pump air bleeding procedure:
- On the front cover of the motor, locate the bleed screw (usually an M4–M6 screw with a slot for a flat screwdriver or an Allen key)
- Hold a piece of cloth close to the screw
- Loosen the screw by ½ to 1 turn – air will start to escape with a soft hissing sound
- Wait until a continuous stream of water (without bubbles) starts to flow
- Tighten the screw securely again
This is the minimum procedure. In a larger system, you must also bleed the radiators and other air vents. If the system is new or has been out of operation for a long time, consider using an automatic air vent at the highest point of the circuit.
Step 7: First start-up – checking parameters
Turn on the pump power supply. On modules with a manual speed switch (typical three-speed Avansa pumps), set the lowest speed and listen – the pump should run quieter than the old one, without knocking, grinding or irregular sounds.
After 5–10 minutes of operation, check the following:
- Supply and return temperatures – the difference should be 10–20 °C during normal operation
- Threaded connections – visually and by touch (are they dry?)
- Terminal box – do not touch it, just visually check for signs of moisture
- Pump noise – a quiet hum is normal, a bubbling sound indicates air in the system (bleed again)
Setting the speed and regulation after installation
Common three-speed Avansa models (e.g., AVANSA 25-4/130) have a three-speed switch on the terminal box or on the side panel. The correct speed selection depends on the size and characteristics of the system. For a smaller family house (up to 150 m²), speed I or II is usually sufficient. For larger systems or underfloor heating with higher hydraulic resistance, speed III is used.
Detailed instructions for setting and hydraulic balancing can be found in the topic Setting and regulating the flow of Avansa pump after installation. General rule: start at the lowest speed and gradually increase it until the radiators reach the desired temperature evenly. Excessive speed = a noisy system, higher consumption and faster wear.
The electronic model AVANSA AUTO 25-4/180 E has automatic regulation – the pump automatically adjusts its performance to the current demand. After installation, it is sufficient to set the operating mode (AUTO, constant pressure, or constant curve) according to the instructions. More about the advantages of electronic regulation can be found in the topic Electronic vs. standard circulation pump Avansa – is it worth paying extra for the AUTO version.
Common installation errors – from real practice
Over the years of practice and hundreds of customers who contact us with problems after self-installation, a few errors keep repeating. Here are the most common ones:
1. Reversed mounting direction
The pump is mounted "backwards" – the arrow points in the opposite direction of the water flow. The system works, but with significantly reduced performance. The customer thinks they have a bad pump. Solution: turn the pump 180 degrees (easy with flanges, problematic with welded flanges).
2. Air in the system after installation
Imperfect bleeding is the cause of bubbling noise and insufficient circulation. The problem is usually solved by re-bleeding the pump and radiators. In new systems, we recommend letting the pump run for 30 minutes, then re-bleeding the system – air can be released gradually.
3. Terminal box oriented downward
A classic error when installing in a tight space, where it is not easy to rotate the pump position. Water or condensation runs into the electrical part and causes a fault or short circuit. When installing in a complex space, it is necessary to rotate the terminal cover (if the design allows) or the entire pump to a position where the terminal box points to the side.
4. Missing ball valves
Installation without shut-off valves at the pump. Every future pump replacement means draining the entire system. Valves are cheap, adding them during installation takes 15 minutes extra, but they will save hours during every service later.
5. Over-tightened or under-tightened threads
Over-tightened flanges break the seal, under-tightened ones leak. Use the correct tightening technique: tighten by hand, then with a wrench with a feeling – when the seal is compressed and resistance increases, tighten at most an additional ¼ turn.
6. Wrong pump selection
A pump with too low a head for the given system, or on the contrary, a too powerful pump in a small circuit. How to choose the right model is explained in the topics How to choose an Avansa circulation pump for your heating system and What pipe thread do I need – 1" or 6/4" for Avansa pump.
Installation in special situations
Replacing an old pump with a different spacing
If you are replacing an old pump with a 130 mm spacing with a new one with 180 mm spacing (or vice versa), simply replacing the pump is not enough – you must shorten or extend the pipe section, or use a compensating transition flange. In practice, the same spacing is most often used – 130 mm for 130 mm, which is standard for Avansa models. Models with 180 mm spacing (e.g., AVANSA 25-4/180) are used where the original connection or specific layout requires it.
Installation in a tight technical space
Boiler rooms in family homes are notoriously cramped. When installing in a narrow space, it is good to first connect the pump to the flanges outside the piping, set the orientation of the terminal cover, and then mount the rest into the circuit. If the flanges can be easily removed from the pump, work with them separately and install the pump last.
Installation in a system with magnetite and corrosion
An older system without a filter may have a significant amount of magnetite (dark sludge) and metal particles in the circulating water. These impurities can damage the bearings of the new pump very quickly – sometimes within a few months. Before installing the new pump, flush the system, install a magnetic filter (sludge trap) at the pump inlet, and consider using corrosion inhibitors. Otherwise, you risk the new pump failing just as quickly as the old one.
Most Frequently Asked Questions (FAQ)
Can I replace the Avansa pump myself, without a plumber?
If you have basic plumbing skills, the system has shut-off valves near the pump, and you can safely work with electricity (or leave the electrical part to an electrician), then yes – pump replacement is technically accessible to a skilled DIY enthusiast. We still recommend having the first start-up and system check performed by a professional, especially if it is a gas boiler. Please note that improper installation can lead to water leaks and damage – follow this guide and call a plumber if you have any doubts.
The Avansa pump makes noise after installation – is that normal?
A soft, even hum is normal. A bubbling or gurgling sound indicates air in the system – bleed the pump and radiators. Tapping or grinding may indicate a foreign object in the rotor (impurities from the system) or damaged bearings. A noise resembling "moving balls" after a few months of operation usually indicates worn bearings due to contaminated circulating water – install a filter. For more troubleshooting tips, read the topic Common faults of Avansa circulation pumps and their solutions.
How long does it take to install an Avansa circulation pump?
An experienced plumber can replace the pump in 30–60 minutes, including bleeding and checking the system. A DIY enthusiast with all the necessary tools and materials should expect 2–3 hours, especially for the first time. If the system does not have shut-off valves and you have to drain the entire circuit, add time for draining and refilling (another hour or two, depending on the size of the system).
Do I need to refill the entire system with water after replacing the pump?
If there are shut-off valves near the pump, it is sufficient to add only the water that drained from the pump area (usually less than 1 liter). If there are no valves and you had to drain the entire system, check the pressure in the expansion tank and refill the system to the operating pressure (typically 1.0–1.5 bar when cold). Do not forget to bleed all radiators and the pump.
Can I install a pump with a different thread than the original one?
Technically yes, but it requires using a reducer (transition from G 1" to G 6/4" or vice versa). This is a common plumbing reducer, but each additional connection is a potential leak point. In practice, we recommend choosing a pump with the same thread as the existing piping. A detailed comparison of threads can be found in the topic What connection thread do I need – 1" or 6/4" for the Avansa pump.
What is the correct pressure in the system after installing the pump?
The operating pressure in the system depends on the building height and the setting of the expansion tank, not the pump itself. For a typical single-story house, the correct pressure when cold (before heating the boiler) is 1.0–1.5 bar. When the system is hot, the pressure will rise to 1.5–2.0 bar – this is normal. If the pressure drops or rises outside these values, the problem is not with the pump, but with the expansion tank or a leak.
Conclusion – what does this mean in practice
Installing an Avansa circulation pump is a manageable task with proper preparation. The key is attention to detail in each step: correct pump orientation, quality sealing of threads, safe electrical connections, and thorough bleeding. These details determine whether the pump will operate quietly and for a long time.
If you are unsure about choosing the right model for your system – whether you need a 130 mm or 180 mm spacing, a G 1" or G 6/4" thread, a three-speed or electronic model – we recommend reviewing other topics in this Knowledge Center. You will find detailed comparisons and practical advice there to help you choose the right one before placing an order.
The complete range of Avansa circulation pumps, including all models mentioned in this article, can be found in the category Avansa on atria.sk.
Do you have a question about this topic?
Having trouble deciding or dealing with a specific situation in your home? Write to us – we are happy to help.