Setting and flow regulation of the Avansa pump after installation
Setting and flow regulation of the Avansa pump after installation
Installing the Avansa circulation pump is only the first step. The truly important part begins only after that – by correctly setting the performance and regulating the flow according to the specific conditions in the system. It is precisely here that it is decided whether the pump will work efficiently, quietly and economically, or whether it will unnecessarily waste electricity, generate noise and shorten its service life. In practice, we see many installations where the installer mounted the pump, turned it to the highest speed and left. The result? A noisy system, an overheated pump, unbalanced circuits and unnecessarily high energy consumption.
This article will guide you through the entire process of setting and regulating after installation – from understanding the hydraulics of your system through the physical setting of speed levels to fine-tuning and checking the correct function. We will also focus on the differences between manual and electronic models, as the procedure differs between them.
Why is correct flow setting so important
The circulation pump fulfils the role of the heart in every heating system – it ensures the circulation of the heat transfer fluid between the heat source (boiler, heat pump, solar collectors) and the heat exchangers (radiators, floor heating, fancoils). The flow must be set so that it corresponds to the actual hydraulic and thermal requirements of the system.
Too low a flow causes the heat transfer fluid to be overheated in the boiler and too cooled in the radiators. Large temperature differences between the supply and return (so-called large delta T) arise, which can lead to uneven heating, boiler burner shutdowns and in the extreme case even to boiler overheating. On the other hand, too high a flow means increased electricity consumption, hydraulic noise in the pipes and fittings, cavitation in the pump and faster wear of the entire system. In addition, with unnecessarily high flow, the water does not manage to deliver enough heat in the radiators – the supply and return have almost the same temperature, which is a sign of an unbalanced, oversized flow.
Correct setting means finding a balanced state – enough flow to meet the thermal needs of the building at the lowest possible pump power consumption and acceptable hydraulic resistance of the system.
What you need to know before the first start-up
Before you start turning the speed switches, it is necessary to have clarity about several basic parameters of your system. You can either find these information in the project documentation or you can estimate them from the character of the building and the heating system.
Thermal power and required flow
The basic physical relationship: the flow required to transfer a certain thermal power is calculated according to the formula Q = P / (ρ × c × ΔT), where P is the thermal power in kW, ρ is the density of water (≈ 1 000 kg/m³), c is the specific heat capacity of water (≈ 4 187 J/kg·K) and ΔT is the temperature difference between the supply and return in Kelvins.
In practice, for a standard heating system with a temperature drop of 80/60 °C (ΔT = 20 K), we get approximately: for every 1 kW of thermal power, we need about 0.043 m³/h of water flow. For a house with a required capacity of 10 kW, we need a flow of about 0.43 m³/h. For modern condensing boilers with a low-temperature system (55/45 °C, ΔT = 10 K), the required flow is double – about 0.086 m³/h for every 1 kW.
For floor heating with a temperature drop of 40/30 °C (ΔT = 10 K), the flows are even higher, but there are usually separate circulation pumps with their own balancing valves in use there.
Head – hydraulic resistance of the network
The second key parameter is the head (H), which expresses the hydraulic resistance of the entire pipe, fittings, heat exchangers and bodies in meters of water column. The longer the pipe, the smaller the diameter, the more elbows, valves and inserted elements – the higher the resistance.
In simple family houses with radiator heating and a main circuit length of up to 50 m, a head of 2–4 m is usually sufficient. Larger objects, systems with regulating valves before each body or extensive floor heating may require up to 5–6 m. The value of the head is ideally determined by a hydraulic calculation. If you do not have it, you can use the rule of 0.06–0.08 m/m of pipe length for typical heating pipes DN15–DN25 as an estimate.
If you are considering the choice of the correct model, in the article What do the numbers in the name of the Avansa pump mean – power, head and spacing you will find a detailed explanation of what the individual numerical designations in the name of the pump mean and how to use them when selecting.
Physical control elements on Avansa pumps
Manual Avansa pumps (e.g. AVANSA 15-6/130, AVANSA 25-4/130, AVANSA 25-6/130) are equipped with a rotary switch with three positions (1, 2, 3), or a small button or sliding switch directly on the pump head. Position 1 corresponds to the lowest performance (lowest flow, lowest power consumption), position 3 to the highest performance.
On most models you will find a switch on the top or side of the motor head. It is important to switch only when the pump is at rest (turned off), or at least at normal operating temperature – not on a cold pump right after the first start, because the mechanical resistance may be higher on cold bearings and the bearings need to warm up and be lubricated by the operating fluid first.
Step-by-step procedure for setting the speed level
Step 1 – Pump air venting before starting
The first step after installation is not setting the speed, but thorough air venting. Air in the pump causes cavitation, noise and in the worst case damage to the bearings (rotating without cooling and lubricating function of water). On Avansa pumps you will find an air vent screw (usually a small slotted screw) on the side or top of the motor head.
Air venting procedure: Close the inlet and outlet (if you have ball valves with the pump set), fill the system with water, open the valves and let the pressure rise to the operating level (typically 1–1.5 bar for a two-storey house). Then carefully loosen the air vent screw – air or a mixture of air and water will come out. Let it flow until only clean water without air bubbles comes out. Tighten the screw. Repeat this procedure after the first 15–30 minutes of operation, as some air will still be released from the pipes.
Step 2 – First start at the medium level (2)
A rule that is almost universal: the first start should always be at speed level 2. There are two reasons for this. First, level 2 is the correct choice for most standard heating systems in family homes and you can immediately see if the system is working. Second, you will not unnecessarily start the pump at full capacity in a system that is not yet fully vented and not yet stable.
Listen after starting. A quiet, soft hum of the motor is normal. Gurgling, cracking or metallic sounds indicate air – return to the venting procedure.
Step 3 – Measuring and evaluating temperatures
Let the system run for at least 20–30 minutes until it stabilizes thermally. Then measure the temperature on the supply pipe (before the boiler) and on the return pipe (before the last radiator, before the boiler inlet). The difference between these two temperatures is your operating temperature difference – delta T.
- ΔT = 15–25 °C – Ideal state for most classic heating systems with a boiler 80/60 °C. The flow is correctly set.
- ΔT > 25 °C – The flow is too low. Increase the speed level or check if some of the circuits have closed balancing valves.
- ΔT < 10 °C – The flow is too high. Reduce the speed level. The system is working unnecessarily intensively.
- For condensing boilers and low-temperature systems it is desirable to maintain ΔT = 10–15 °C, which requires a higher flow.
- For floor heating ΔT = 5–10 °C at low temperatures (35–45 °C supply).
Step 4 – Fine adjustment of the level
If you are at level 2 and delta T is out of range, switch to level 1 or 3 and measure again after another 20 minutes. The goal is to get into the ideal delta T range and at the same time ensure that all radiators in the system receive enough heat – i.e. that heat is distributed evenly.
Note: Setting the pump alone cannot replace the hydraulic balancing of the system. If some radiators are significantly warmer than others, the problem is in the unbalanced valves, not just the pump flow. Pump setting is a global parameter – all circuits will get more or less, but the relative distribution between them does not change.
Setting up the electronic circulation pump AVANSA AUTO
The electronic circulation pump AVANSA AUTO 25-4/180 E operates on a completely different principle than manual models. Instead of fixed speed settings, it features a frequency inverter and an integrated microprocessor that continuously evaluates system conditions and automatically adjusts motor speed to current demand.
Operating modes of AVANSA AUTO
The electronic pump Avansa AUTO typically offers the following operating modes, which you can set using the control button and LED indicators on the display:
- AutoAdapt (automatic adaptive mode) – The pump automatically and gradually searches for the optimal Q/H curve for your system. This process takes several days of operation. It is the simplest way to set up the pump – simply activate this mode and the pump will adjust itself. We recommend it for most standard installations.
- Constant pressure (Δp-c) – The pump maintains a constant head regardless of flow. Suitable for systems with thermostatic heads, where flow varies according to demand.
- Proportional pressure (Δp-v) – The head decreases as the flow decreases. Advantageous for systems where parts of the system are switched off (e.g., floor heating loops with separate control). More efficient than constant pressure.
- Constant speed – Equivalent to manual speed settings 1, 2 or 3. You set a fixed speed and the pump maintains it. Suitable for simple non-zoned systems.
For a standard radiator system with thermostatic heads, we recommend the proportional pressure mode (Δp-v) or AutoAdapt. For floor heating without thermostats and with a fixed flow diagram, the constant speed mode with a lower set output may be more suitable.
Setting the desired head for the electronic pump
When manually setting the pump in Δp-c or Δp-v modes, you must also enter the desired head (setpoint). This should correspond to the hydraulic resistance of the most unfavourable (hydraulically furthest) loop at full opening of all control valves. If you do not have this calculation, start with a value of 2 m and gradually increase it until heating is evenly functioning in all rooms.
Do not set the value too high – the electronic pump does regulate, but if the setpoint is unnecessarily high, it will work unnecessarily hard even at low system load. The advantage of electronics is then lost. Proper setpoint setting is key to energy savings.
A more detailed comparison of manual and electronic Avansa circulation pumps can be found in the article Electronic vs. standard Avansa circulation pump – is it worth paying extra for the AUTO version, where specific electricity savings calculations for the season are also included.
Hydraulic balancing of the system – an essential step that the pump does not replace
Even if you set the pump to the ideal performance, without hydraulic balancing you will never achieve even heat distribution. Hydraulic balancing means setting the flow through each radiator (or floor heating loop) so that each one receives exactly the amount of heat it needs according to its capacity and the room's heat loss calculation.
Hydraulic balancing is carried out using pre-set thermostatic valves (e.g. Danfoss RA-N, IMI Heimeier Regulux) or balancing valves on the return (e.g. Stad from TA Hydronics). Each valve has a scale for setting the flow in l/h or m³/h. The values to be set are based on the heat loss calculation for each room.
Practical balancing procedure in short: Set all valves to maximum opening. Start the system. Measure the temperatures in all rooms after 1–2 hours of operation. Rooms that are warmer than desired should be throttled (reduce flow via the valve), and vice versa. Repeat this iterative process several times until the temperatures are balanced. Only then fine-tune the pump performance according to delta T.
Specific settings for typical installations
Single-family house 120 m², boiler 15 kW, radiators, temperature drop 80/60 °C
For such a typical system, the optimal flow is around 0.64 m³/h (ΔT = 20 K at 15 kW). The head for a 60 m DN20 pipe loop will be about 3–4 m. Suitable pump: AVANSA 25-4/130 or AVANSA 25-6/130. Setting: speed 2. If ΔT exceeds 22 °C, switch to speed 3. If it is below 12 °C, keep it on speed 1.
Apartment in a panel building, boiler 8 kW, floor heating 70 m², temperature drop 40/30 °C
Floor heating with ΔT = 10 K at 8 kW requires a flow of approximately 0.69 m³/h. The hydraulic resistance of a collector system with 6 circuits is typically 2–3 m. The ideal choice here is the smaller model AVANSA 15-6/130. Setting: stage 2, or possibly stage 3, if distant circuits are cold. Note that with floor heating, the pump usually operates through a mixing three-way valve – the pump setting must also be consistent with the setting of this valve.
Old apartment building, gravity system converted to forced circulation
When renovating gravity systems (older pipes DN32–DN50, short runs, large radiators), hydraulic resistances are low, but required flows are higher. In such cases, stage 1 or 2 is suitable, with monitoring of delta T. An unnecessarily high stage causes noise in the pipes and, with old radiators, even abrasive damage from corrosion loosened deposits.
Most common errors in setting and their consequences
From practice, we know that the most common error is leaving the pump permanently on stage 3, justified by the phrase "better safe than sorry". Result: unnecessary electricity consumption (the difference between stage 1 and 3 can be up to 3–4 times in power), a noisy system, shortened pump life and of other components. We have often seen pumps whose motors were overheated after years of operation at full power, precisely because the minimum flow for cooling was exceeded in the opposite direction – the pump was operating in a zone of too low resistance and thus too high flow, which is also not ideal.
Second error: switching speeds when the system is cold or fully heated without subsequent delta T check. You set stage 2, turn the thermostats to maximum, and leave. After a week, you return and the radiators are unbalanced. The correct procedure is always to check delta T and the uniformity of heating after each setting change.
Third error: ignoring hydraulic noise. If the pump hums, gurgles or makes other sounds, it is not normal and changing the speed setting will not solve it. Causes may include air in the system, an unbalanced system, cavitation or mechanical failure. More about diagnosing faults can be found in the article Common faults of Avansa circulation pumps and their solutions.
Energy efficiency and setting optimization
Correct setting of the Avansa pump has a direct impact on annual heating operating costs. The difference in power consumption between individual stages is not small: a typical manual pump 25-6 has a power consumption of around 35–45 W at stage 1, around 65–80 W at stage 2, and up to 90–110 W at stage 3. The pump operates during the heating season (5–6 months) 24 hours a day. At stage 3, this means a consumption of about 450–530 kWh/year, while at stage 1 it is only 150–200 kWh/year – a difference of 250–350 kWh/year. At an electricity price of 0.22 €/kWh, this is a saving of 55–77 € per year. Over 10 years, this gives 550–770 € in savings just by correctly setting the pump stage.
The electronic pump AVANSA AUTO goes even further – in adaptive mode, it can operate with a power consumption of only 5–15 W in warm weather (when thermal demand is low), which is a dramatic saving compared to fixed manual settings. When comparing the entire season, the electronic pump can consume only 50–80 kWh compared to 300–500 kWh of a manual model at a medium stage.
Seasonal adjustment of settings
A single setting for the entire year is not optimal. Most experienced installers recommend:
- Fall/spring (transition period) – Stage 1 or 2. Heat losses are low, the system does not need maximum flow.
- Winter (freezing period) – Stage 2 or 3. Higher thermal output requires higher flow for heat transfer.
- Summer (possibly active cooling or DHW heating) – If the pump is used only for heating domestic hot water through a heat exchanger, stage 1 is usually more than sufficient.
With the electronic model AVANSA AUTO, this change is handled by the automation – another argument for investing in the electronic version, especially for long-term operation.
Verifying correct setting – check list
After completing the setting, check the following points:
- The pump operates quietly without unusual sounds (humming is normal, gurgling is not)
- Delta T between supply and return is in the range of 10–25 °C (depending on the type of system)
- All rooms are evenly heated within 1 hour after starting
- Pressure in the system is stable (the manometer on the boiler shows a constant value, without drops)
- The safety valve does not open – pressure does not exceed the set value
- Power consumption of the pump (if you have a wattmeter) corresponds to the declared values for the given stage
- With an electronic pump: the LED indicator shows the active selected mode
Special situations and their solutions
The pump starts, but heating does not work
If the pump is running (you can feel the vibration, hear the motor), but the radiators are cold, the most likely causes are: an underventilated system (airlock blocks the flow), closed ball valves on some section, or incorrect flow direction (the pump is reversed – check the flow arrow on the pump body and compare it with the actual connection direction).
Noisy pump despite correct setting
If you have set the correct stage and bled the system, but the pump still makes noise, check: Is the pump securely mounted and vibration-isolated from the piping? Do you have flexible connections or rubber seals that dampen vibrations? Is the noise related to hydraulic noise in the fittings (thermostatic valves turned to zero, which causes so-called singing)?
The pump overheats and shuts off
The thermal protection of the pump may react to long-term operation with zero flow (closed system, blocked valves) or to excessively high medium temperature above 110 °C. Check the temperature of the working medium and ensure minimum flow even when thermostats are closed (e.g., a bypass or at least one permanently open radiator).
Frequently asked questions (FAQ)
To what stage should the Avansa pump be set for a new family house?
For most new builds with a condensing boiler and a low-temperature system (floor heating or low-temperature radiators), we recommend starting at stage 2. After 30 minutes of operation, measure the temperature difference between the supply and return pipes. If the difference (delta T) is 10–15 °C, the setting is correct. For older houses with high-temperature radiators and a temperature drop of 80/60 °C, the target delta T is 18–22 °C at stage 2 or 3.
Can I leave the pump permanently on stage 3?
Technically yes – the pump will not be damaged by running at the highest stage. The problem is unnecessarily high electricity consumption (up to 3–4 times higher than stage 1), noise in the system, and faster wear of fittings and thermostatic valves, which are subjected to higher pressure stress. Also, excessively high flow causes a low temperature drop, which reduces the efficiency of the condensing boiler. Permanent use of the highest stage is justified only during strong frosts when the thermal load is maximum.
What is the difference in electricity consumption between stages 1, 2 and 3?
For a typical Avansa 25-6 pump, the power consumption is around 35–45 W at stage 1, around 65–80 W at stage 2, and around 90–110 W at stage 3. During annual operation during the heating season (5 months, 24h/day), this gives a difference of 200–300 kWh between stages 1 and 3, which at current electricity prices represents a saving of 44–66 € per year. Over the lifetime of the pump (10–15 years), this is 440–990 €.
Why are some radiators still cold after setting?
The pump setting affects the overall flow in the system, but does not affect the distribution of flow between individual circuits. If some radiators are still cold, the cause is hydraulic imbalance – nearby radiators "take" a larger flow at the expense of distant ones. The solution is hydraulic balancing through pre-setting of thermostatic valves, not increasing the pump stage. Increasing the stage will give the warm radiators even more heat, but the distant ones still won't get enough.
How can I tell that the pump has an incorrectly set performance?
Signs of excessive performance: hydraulic noise in the pipes and valves (whistling, gurgling), very small temperature difference between the supply and return pipes (less than 5–8 °C), pipe vibrations. Signs of insufficient performance: large temperature difference (over 25–30 °C), uneven heating, the boiler switches to safety shutdown due to overheating, slow system response to thermostat setting changes.
Do I need to reset the pump before the heating season after summer?
For manual pumps Avansa, we recommend that you always unscrew the air vent screw before the season and check that the system is not air-locked (air naturally escapes from the system during the summer). The speed setting usually does not need to be changed, unless the system conditions have changed. For the electronic version AVANSA AUTO, no intervention is necessary – the pump automatically adjusts its performance to the current demand after a few days of operation. In any case, it is useful to check the pressure in the expansion tank and inspect the pressure gauge.
Conclusion
Correct setting and regulation of the Avansa pump flow is not a one-time action – it is a process that starts with deaeration, continues with setting the level according to the measured delta T, and is completed by hydraulic balancing of the entire system. The result of a properly set system is even and comfortable heating, minimal electricity consumption, and long service life not only of the pump, but also of other system components.
If you are considering the installation of a new pump or the replacement of an old one, take a look at the full range of Avansa models on the page atria.sk/avansa-2/ – from the compact AVANSA 15-6/130 for small apartments up to the powerful AVANSA 25-4/180 for larger family homes and two-storey buildings. If you are looking for maximum energy efficiency without manual interventions, the electronic version AVANSA AUTO 25-4/180 E will take care of optimal settings by itself.
Further practical information on installation, selection and maintenance can be found in the articles
Having trouble making a decision or dealing with a specific situation in your home? Write to us – we are happy to help.Do you have a question about this topic?