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Wilo Pump Speed Setting


Wilo SE with its headquarters in Dortmund is one of the world's leading manufacturers or pumps and pump systems for heating, air conditioning and cooling technology, as well as for water supplies and sewage treatment and disposal. The company has over 65 subsidiaries and over 7,000 employees. The economic supply to buildings increasingly demands the use of innovative systems from optimally configured components. Whether in a detached or semi-detached home, industrial, commercial or public buildings, hospital or hotel.


  • Variable speed heating zone circulators: this article describes brands & models of forced hot water heating system circulator pumps whose motor speed or circulating speed can be set to varying rates. We describe both older obsolete variable speed circulator pumps and modern currently-available models including manufacturer brand, model, and circulator pump sources.
  • Flow rate Depends on the pump type, see catalogue Max. Delivery head Depends on the pump type, see catalogue Speed Depends on the pump type, see catalogue Mains voltage 1230 V ±10% as per DIN IEC 60038 Frequency 50/60 Hz Nominal current see name plate Energy Efficiency Index (EEI) see name plate Insulation class see name plate.

– Double pumps Wilo-TOP-ED C – – – – – 109 Automatic pumps – Single pumps Wilo-Smart. Autopilot Automatic adjustment of the pump output in set-back phases, e. Boiler setback operation during the night. Speed, water condition) and installation/usage situation and may re. He said that on its highest speed, it zooms through taking a lot of the heat away quicker. I have a Weil Mclean gas hot water boiler thats about 30 yrs old with baseboards. 2 zones(one for downstairs, one for up), a digital thermostat, all replacement windows, doors, blown in cellulose in walls, and energy saving window treatments.

Mr Morgan Warren Ross
Second Avenue, Centrum 100
Burton on Trent
DE14 2WJ

Wilo has launched its new CAT5 Booster set into the marketplace. Since 1999 it has been illegal for commercial organisations to put a hosepipe directly on to a tap to wash down machinery or a vehicle. It is essential to incorporate a backflow prevention device to ensure no back flow and syphonage leading to contamination of the potable water supply by bacteria returning up the hose pipe into the mains water supply.

The new Wilo CAT5 booster set incorporates a 115 litre polypropylene break tank which is supplied complete with a WRAS approved AB air gap. The overflow and weir are screened to enable connection to hygienic systems.

Applications for this equipment include such uses as no domestic hose union taps, bin and vehicle washdown, garden irrigation, laboratories, mortuary and embalming equipment, butchery and slaughter-house equipment.

The units are supplied with either a single fixed speed pump or a variable speed pump as specified. The single speed sets are controlled via a pressure switch, DOL motor starter and a run on timer, whilst the variable speed setsare controlled via a pressure transducer and motor mounted inverter.

All come complete with a non-return valve, pressure gauge, 8 litre vessel and outlet isolation valve and a tank draincock. The water level in the break tank is controlled via a BS1212 equilibrium float valve which provides a flow rate of 1.2l/s at a minimum inlet pressure of 1 bar. Low level protection is provided via a side mounted float switch.

The booster set monitors the system pressure and as demand increases the pressure will fall and the pump will start and continue to run, until demand has stopped and pressure increases to the set point. The fixed speed booster sets have a run on timer that overrides the pressure switch for a set period to minimise the number of starts per hour.

For more information on these quality units, visit or call Sales on 01283 523000.

If you’re wondering how to choose the best speed setting for your central heating pump, then you’re not alone. It’s one of the most frequently asked questions about central heating pumps.

Although it appears confusing at first, finding the most efficient speed setting for your pump is actually quite simple – and this article will show you how to do it.

What does the central heating pump do?

A central heating pump’s job is to pump the hot water that’s just been heated by the boiler around the radiators in your home, and back to the boiler to be re-heated. Read more about Central Heating Pumps.

Why does it have more than one speed?

Many central heating pumps have more than one speed setting, which can be confusing. So why do pumps have multiple speed settings?

Every central heating system is different. Different numbers and sizes of radiators. Different room layouts and lengths of pipe run. Different diameters of pipe and different sizes of boiler. Etc, etc.

All these things affect the amount of friction between the water and the system, which the central heating pump has to overcome.

It stands to reason that there’s no one perfect pump speed that works for every central heating system – therefore it makes sense for manufacturers to allow you to adjust the speed of your central heating pump so it’s just right for your system.

What if the pump is running at the wrong speed?

If the original installer set the pump speed correctly for your system, then it’s best not to change it – but since many installers seem to always set the pump to “medium” and hope for the best, many people are tempted to try to optimise the speed themselves.

If your central heating pump is running too fast, then it’s a waste of electricity, since it uses more electricity to pump the water at high speed rather than a lower speed. So your electricity bill will be higher than it needs to be.

Adobe creative cloud mac. If on the other hand your pump is running too slow your radiators may not heat up properly.

Too fast

  • Wastes Electricity
  • Noisier – Pipes as well as pump itself
  • Boiler may cycle rapidly if return temperature is too high (water has moved through the radiators too fast, so the water hasn’t had long enough to lose much heat to the radiators)
  • Air in system – one radiator often needs bleeding
  • Cavitation in pump (wears more rapidly)

Too slow

  • Radiators don’t warm up properly – water is spending too long in the radiators, and cooling down too much
  • Boiler overheats and cuts out
  • Return temperature too low

Grundfos Central Heating Pump Showing 3 Speed Settings (c) hobbs_luton via Flickr

How much electricity does a central heating pump use?

As you might expect, this varies with the size and model of central heating pump.

It also varies significantly with the pump speed – which is why, other things being equal, a lower speed setting is desirable.

As an example, this Grundfos pump (pictured) has three settings:

1. 40 Watts
2. 65 Watts
3. 105 Watts

So the highest speed uses more than double the electricity of the slowest speed.

Some modern pumps claim to use far less power, eg the Wilo Stratos PICO Commercial Circulating Pump claim to use as little as 3 Watts, though we recommend treating such claims with caution.

What different types of speed setting are available?

Single speed

It’s probably still possible to buy a central heating pump that only does one speed, but they’re not very common. Most pumps now on the market offer at least 3 distinct speeds.

Multiple fixed speed

Most central heating pumps, like the Grundfos UPS2 15-50/60 have three individual speed settings to choose from. A few have more, like the Grundfos Alpha 2L 15-60 which offers 7 pre-set speeds.

Variable speed

Wilo Usa Pumps

Some modern pumps like the Wilo Stratos PICO Commercial Circulating Pump offer just a continuously variable speed setting.



Some brands, eg Wilo offer a combination of three fixed speeds or a continuously variable speed.

How to set central heating pump speed

The actual mechanism for setting the speed varies depending on the brand and model of the pump in question. Usually there’s a control fairly clearly visible on the pump.

For example the Grundfos UPS2 15-50/60 has a button and three lights to indicate the selected speed.

Other pumps, like the Flomasta range have a rotary dial on the front of the pump which allows you to select the desired pump speed.

How to find the best speed setting



The simple answer is to use the lowest speed at which the system works properly without any problems – as that will save electricity.

So you can try reducing the speed of your pump from high to medium or medium to low, and check that all the radiators still get hot, and that the boiler doesn’t overheat and cut out. You can always increase the pump speed again if you encounter any problems.


In theory, the most efficient way to set up a central heating system is so that there’s an 11 or 12 degree difference in the temperature of the water leaving the boiler, and the water returning to the boiler from the radiators. It may not always be possible to achieve this in practice.

Changing the speed of your central heating pump will affect the temperature of the returning water.

If you have a condensing boiler, you’ll want to make sure that the return temperature doesn’t exceed 55 degrees C, or the boiler will be unable to work efficiently.

If you can measure the flow and return temperatures accurately with a thermometer, you can try the available pump settings, to see which one gets closest to the ideal efficiency.

Obviously you need to also look out for other undesirable effects, like radiators not warming up properly, or excessive noise, either from the pump, or the pipework, or any funny noises from the boiler.

Also, don’t forget that higher speed settings use more electricity to pump the water, so choose the slowest setting that works well.

Signs that pump speed may need adjusting

If your radiators have been bled, but still aren’t getting hot, it may be a sign that the pump speed is too low. Try increasing it and see if it helps, but watch out for the boiler overheating and cutting out, additional noise, and radiators needing bled more frequently.

Wilo Pump Catalog

If the pump or pipework is noisy, or one or more radiators often need to be bled, it may be a sign that the pump speed is too high. Try reducing it and see if the problems go away – but check that the radiators are heating up properly and the boiler is not cycling too fast.


Wilo Pump Distributor

Central heating pump speed selection may seem confusing at first, but once you understand why different speeds are available – and some of the problems you’re likely to see if the speed is too high or too low – it becomes quite straightforward to try the different speed settings your pump allows, and find the best speed for your system.