DWP Services have been using a range of variable speed pump controller for many years. We have found many of them have some advantages and some disadvantages. Here we will discuss a few to give you some guidance on what can be used.

After some years we have narrowed down inverters keeping in mind cost and performance, here is a short guide.
Motor mounted and wall mounted inverters –

Grundfos MGE and Saver

Grundfos are the biggest pump company in the world. Their reliability cannot be beaten and the technology has clearly been heavily invested in. This ensures Grundfos stays as the household name of pumps and inverters bringing complete peace of mind. The main variable speed drives is the soon to be discontinued MGE inverter and the new Saver 1 and 2 inverter. The MGE inverter has a deep parameter list for a knowledgeable engineer to fine tune to the maximum for complete efficiency and peace of mind.  But on the other hand the MGE inverter will work with the right configuration file and basic set up. It may not be running to maximum efficiency but will deliver water where you want it year after year.

The Saver inverter is the newer edition to the Grundfos family, this has a hugely expanded menu giving the customer complete configuration. Reliability and quality has not been compromised and reliability is still at the top of its game.

Grundfos are notoriously expensive to their top end products but believe you get what you pay for, if you want a long term reliable solution this may be the manufacture for you.

Xylem Lowara Hydrovar

We are now on the 5th generation of hydrovar. The years have seen complete redesigns of the hydrovar inverter but in all truth the menu and performance values have not changed too much. If you have a hydrovar it is most lijeky its the 3rd 4th or now 5th generation. Luckily enough no matter which one of these you have you can now buy an inverter to communicate with any model through its compatability software. The hydrovar is a motor or wall mounted inverter that has a pump specific set up generally used for water boosting. The excellent mulit-pump communication RS-485 is a real game changer in the pump world due to its ability to constantly keep system pressure whilst adjusting parameters or switching between units. The Hydrovar is most definitely a highly regarded inverter in the market although fairly expensive.

Coelbo Speedomatic

DWP Services is a fan of the speedomatic water cooled inverter. These units are cost effective, user friendly and reliable. The speedomatic can supply up to a 10AMP water pump and has an integral pressure and flow sensor so no need for extra wiring. They may be made out of plastic and a little bulky but now come with a LCD backlight display and a Volt Free fault contact giving the customer the ability to install and alarm to the unit in fault conditons.

Nastec Vasco

We believe this is a strong competitor in the variable speed market. This unit is wall or motor mounted just like the hydrovar and is very cost effective. The menu system is easy to navigate whilst giving a huge amount of adjustable parameters


If you require technical advise or any more information on any of these products contact DWP Services now for expert advice.

Xylem 214

Hoping to answer a few of your questions here. Anymore questions get in touch

Q – What are some different types of water pumps?

Well pumps, borehole pumps, sump pumps and multistage pumps are some of the different types of water pumps that you can find. Water pumps can be useful in both businesses and homes to bring or move out water. That’s where DWP services come in. Here is a bit about each of the above.

Well pumps These are often used in more remote areas. Wells used to be a main source of water for many people and are still widely used across the world. Well pumps were designed to create a high flow of water and a substantial pressure to ensure even the most modern of homes can run directly from a single well pump.

Borehole Pumps Invented for high pressure at low flow for the deepest of boreholes. In most cases these pumps are installed in a borehole and the water is then pumped into a holding tank. The water is then either gravity fed to its final destination or pumped once again to ensure a sufficient flow are pressure for the end user.

Submerisble pumps can remove water in a basement or an external underground tank. They come in many sizes to work in a domestic application right up to the most demanding commercial installations. No matter if you have a basement that floods now and then or a storm a sewage application there is a submersible pump that can can for you.

Multistage pumps Found in higher pressure at high flow applications, these pumps come in end suction (horizontal) or vertical orientations. They are used across the world for pump clean water to its final destination from a water authority application right through to hotel.

Q – How much of a submersible Water Pump is submersed?

The whole thing is submersed. A submersible pump must be fully and completely submerged in fluid, including the motor which is fixed to the body of the pump.

Q – What happens if a Water Pump runs dry?

Pumps use water to cool the internal impellers, when a water pump runs dry it is no longer being cooled. Impellers are either metal or plastic, and both of these materials do not cope to well and getting hot! The mechanical seals are made of ceramic which then start to quickly wear and end up leaking. Ceramic used throughout a multistage pump can also shatter causing critical failure forcing the entire element to be repaired or in a lot of cases replaced.

Q – How high can I lift Water with a Pump?

A common question I get asked without doubt. Even though we refer to it as suction lift, pumps actually do not lift liquid. What they do is create a void by evacuating the air in the line. Atmospheric pressure on the liquid then pushes it up the hose and into the pump. Simple, right?!

Pumps tend to lift higher than most manufactures will recommend but if possible it is always best to avoid suction lift. When a pump is lifting water and not variable speed your pump does not know if it gets air locked it therefore runs dry and unless you spot it early and prime it once again critical failure is likely. Luckily we have many other solutions to hand such as inverters to set dry running alarms or even well pumps!

 Q – What is Bar?

The bar is a unit of pressure equal to 100 KiloPascals (kPa is the abbreviation). This is roughly equal to the atmospheric pressure on Earth at sea level.
Most mains municipal water suppliers within the UK provide water pressure at an average of 2 bar. Some areas get mains water pressure as high as 3 bar. 1 bar is equal to 14.5psi.

Q – What is Cut In and Cut Out Pressure

Cut In Pressure is the set pressure that the water pump turns on at. Alternatively, the Cut Out Pressure is set pressure that the water pump turns off at. Simple as that!

Q. Any common reasons for Pump failure?

The most common reasons are probably from the following list:

  1. The tank size being too small for the job it has to perform
  2. Wrong choice of pump
  3. Running dry
  4. Short cycling

Q. What size or horsepower of pump do I need? 

Generally higher horsepower pumps put out more water. You’ll find different models of jet pump are designed differently. A ½ HP pump can provide water to a small house with one bathroom and just a couple people.

If you add to that a second bathroom that might be used at the same time as the first, then going with higher horsepower is going to provide the extra water you’ll need.

With examples of a houses with multiple bathrooms, multiple people, then you probably need to go with one of the 1 HP models.

Differences between submersible and immersible pumps

The terms submersible and immersible sound similar, however, these two are strikingly different and I want to explain to you why.

Submersible pumps are a heavy-duty type pump for heavy-duty jobs. Immersible pumps are a more cost-effective option for lighter-duty applications in a nutshell but let’s delve into further detail.

Submersible Water Pumps

Submersible water pumps have many industrial uses. They are completely enclosed and the motor is integral with the pump which is designed to run continuously submerged in water.

Submersible pumps are built with frames that are precision machined to ensure a tight fit between every component of the motor and pump. Submersible pumps typically have a specially designed dual seal design where the outer seal is lubricated and the second seal is located in an oil bath chamber in, or below, the motor housing for seal lubrication.

Although built for continual submersion generally these water pumps can also be placed in dry environments that only flood under rare circumstances. Based on their design, the motor may require an external source of liquid for cooling or have an intermittent run time rating when run un-submerged.

These pumps are typically used in applications where they help manage things like sewage, storm & drainage water and oily water.

Immersible Water Pumps

Immersible water pumps have motors that are built with the intent that they may be submerged and continue running in the event of the rare flood. They are, however, not meant to be submerged under normal everyday circumstances.

These motors are built specifically to operate in a dry environment. They are built with a sealing system that can withstand being submerged under up to 30 feet of water for up to two weeks. Immersible water pump motors are designed with a drive endplate packed with moisture-resistant grease, instead of the oil chamber found in a submersible water pump.

Immersible water pumps are generally easier to service and are cheaper to operate and maintain than the aofrementioned submersible water pump. They are appropriate for use in underground storm water pump stations where the pump gallery is designed to function as an incidental secondary wet well for the very rare major flooding event. After this motor is immersed, it must be removed for inspection and a bearing change.

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