Customer Services FREEPHONE: 0800 008 6405 Email:

Pump Sales Direct Blog

  • How does a coolant pump work?

    Think you might need a coolant pump? You’ve come to the right place. By coolant pumpleaning on our years of experience in the pumps industry, we have created this post that will tell you everything you need to know about coolant pumps. For everything from sizing requirements to compatibility with different materials, you’ll find it all here.

    What is a coolant pump?

    As you can probably guess by the name, the role of the coolant pump is to ensure that coolant is distributed evenly throughout the structure in which it is situated. Coolant is any substance (generally speaking a liquid or gas though) that is used to regulate the temperature of a system. In industrial processing, the term ‘heat transfer fluid’ often replaces the term ‘coolant.’ Coolant pumps are used in a range of industries, which has led coolant pumps to specialise in a number of different ways.  Typically though, a coolant pump is a submersible multistage centrifugal pump. Put in simpler terms, a coolant pump is capable of operating fully submerged in liquid, and works by imparting energy from the rotation of multiple shaft-driven impellers to the coolant.

    Secondly, it is important to differentiate machine tool coolant pumps (which are the kind we deal in here at Pump Sales Direct) from the coolant pumps you might find in your car, or further still, in a nuclear reactor. Although functionally similar - they all work by pumping a coolant around - there are a number of subtle differences that distinguish them from one another in practice. A coolant pump designed for a pressurised water reactor for example, is more elaborate and technical as it needs to be able to transfer heat in a steam generator to water across different pressure circuits. Meanwhile, in car engines and machine tools, the role of the coolant pump is more straightforward as they are only needed to circulate coolant irrespective of pressure differentials.

    How do I know if I need a coolant pump? And if so, what kind do I need?

    Because coolant pumps have so many industrial applications (everything from boiler feeds to industrial washing machines) it can be difficult to work out whether you actually require one, and narrowing it down to a specific model can be even tougher. However, once you have established your flow, pressure and length requirements, picking out the right coolant pump is relatively uncomplicated. On the other hand, if you are still unsure when it comes to the technical details, the flexibility of the Grundfos range of SPK coolant pumps makes them a feasible choice in a multitude of scenarios.

    At Pump Sales Direct, alongside the very popular Grundfos SPK range, we stock a variety of machine tool coolant pumps. Have a look at this extensive range of machine tool coolant pumps here.

  • Condensate Pumps Explained

    condensate pumpcondensate pump could be the only thing standing between you and the overdue resolution of the dampness issue in your home that has been lingering for far too long. Unfortunately, the inner workings of condensate pumps aren’t exactly common knowledge, and this lack of familiarity and understanding on the part of homeowners can often be the stumbling block that prevents an issue like this from being resolved much quicker. With this in mind, Pump Sales Direct have put together this guide that covers everything you need to know about condensate pumps.

    How is condensate formed?

    In the process of heating your home, heating systems also produce latent water vapour. As is inevitable in any form of HVAC process, steam is produced - giving rise to the welcome temperature change that the product is designed to. However, when this same steam cools, it condenses into water droplets and becomes a waste product.

    Why is it so important to remove condensate?

    As well as causing dampness or even flooding in large quantities, the latent water vapour (or condensate) that accumulates below your boiler can also contain traces of potentially dangerous contaminants. These factors serve to underline the importance of finding a way to dispose of condensate properly.

    What are condensate pumps and how do they work?

    Put simply, condensate pumps help get rid of all of the steam (or condensate) that can build up in your HVAC (heating, ventilation and air conditioning) system, condensing boiler or refrigerator over time. By transferring energy from a motor to the condensate itself via a rotating impeller, the pump is able to remove condensate quickly and effectively. Generally speaking, there are only relatively small amounts of liquid involved and condensate pumps often have small tanks for exactly this reason. The tanks allow them to store condensate until levels increase enough to activate the float valve, whereupon the condensate is released into a drain.

    How do I know if I need a condensate pump?

    Assuming it isn't the fault of your own central heating pump, finding dampness or worse in the pipes that service your HVAC is the clearest illustration you can find of the need for a condensate pump, but there is another important telltale sign you should be on the lookout for.

    What normally distinguishes a condensing boiler that is in need of an accompanying condensate pump, and one that isn’t, is location. Enough distance from a convenient drain, or positioning well below ground level, will prevent a boiler from ridding itself of condensate on its own.

    Typically, boilers are reliant on the natural action of gravity to drain condensate away. A condensing boiler located in a basement then, is poorly placed to take advantage of the gravitational pull that so many others boilers rely on. If your condensing boiler is in your basement, or a similarly ill-equipped location, and is not currently being serviced by a condensate pump, it is well worth exploring the possibility of purchasing one.

    For a range of condensate pumps, shop online at Pump Sales Direct.

  • Managing the global water shortage crisis in 2018 and beyond

    flotec pumps

    Whilst some areas are weathering widespread flooding, others, like Cape Town and California, are experiencing water shortage crises. How we choose to manage our most precious commodity may well define us as a species over the coming century. But in order to address the crisis, we first need to understand what it is.

    The causes of the coming water shortage crisis

    Overconsumption, an over-burgeoning global population (and its subsequent demands on agriculture), and anthropogenic climate change are the main contributors leading to global water shortage problems. The current crisis in Cape Town for example—a City on course to set records as the first to officially run out of water—is partly to blame on population growth, coupled with three years of very low rainfall.

    A consequence of the water crisis

    More than two-thirds of our planet is covered in water. Yet it is a remarkable fact that as little as 2.5 per cent is suitable for our drinking—and the vast majority of that small fraction is also inaccessible to us, being stored away in the glaciers of Greenland or Antarctica, or as permafrost or groundwater.

    We have already seen the first of the resource wars of the twenty-first century, those played out in Middle East over oil. It’s possible in the future wars may be waged over possession of water. This may not be as far off as one would think: Ethiopia is in the process of constructing a dam over the River Nile—much to the chagrin of Egypt. And there is at least some evidence linking the Syrian migrant crisis of 2015 to a prolonged drought.

    So, though it doesn’t seem obvious at first, a lack of water can trigger unrest in areas of national security for the Western powers.

    How we, the global community, can prevent the crisis

    Education is key, and farmers across the world are already learning about more sustainable ways to raise livestock, in addition to planting drought-resistant crops, turning to drip-irrigation practices and taking measures to capture and store as much rainfall as possible.

    It might seem this crisis will disproportionately affect the developing world, but that is not to say the education programmes should end there. On the contrary, it is vital that we take the necessary steps, so that citizens of the developed world learn to understand the importance of water, to respect it, not to waste it and—most importantly, not to take it for granted.

    How you can do your bit with Flotec pumps

    A perverse flip-side of the global weather conditions coin is that, where some regions are set to endure exacerbating droughts and dryness, other regions will experience more intense rainfall, with flooding being a likely consequence.

    Flotec pumps are ideal for dealing with dirty water. Even water that contains large, suspended solids as flood run-off generally does. This makes it ideal for draining pools or ponds overwhelmed with detritus in the flood, as it operates as normal even at fully-submersed depths of up to seven metres. And, as the pressure grows for us to collect and do more with our freshwater, pumps such as this one may play an increasingly important role in the recycling processes.

    If this post has interested you, take a look at some of the articles on our blog which further explore the topic of water management, such as how we treat wastewater here and how centrifugal pumps will become increasingly relevant in humankind’s management of the crisis.

  • Fighting off floods: Six tips and tricks

    Floods count as some of the biggest and most costly natural disasters to befall the British people—and the long-term forecast is bleak as climate change predicates longer and more intense rainfall.

    So, get your wellies on, your umbrella out, and give this a good read. The chances are, unfortunately, you’ll need it.

    Know the risk

    In England and Wales more than five-and-a-half million homes are at risk of flooding, and despite the increasing concerns over exacerbated flooding more than 10,000 new homes are built across flood-prone areas in Britain every year.

    Some areas, however, are more prone than others. And though the Environment Agency has said it is impossible to completely protect your property, the Agency can help homeowners with a “flood plan” that could keep you and your property safe.

    Make your house less permeable

    Arguably the best form of damage limitation is to prevent the water from entering your home in the first place. Water often seeps in through doors, air bricks, and other gaps. A form of reverse pressure can even force water to back-up through the sinks, even the dishwasher.

    Fortunately, guards and covers can be fitted in times of emergency, and “non-return” values can be fitted to pipes susceptible to backing up. Be sure to look for any flood-prevention products with the “kitemark” accolade. The kitemark is a symbol that the product has been tested to the rigorous standards of the Environmental Agency.

    Limit the damage with Clarke pumps

    clarke pumps

    The Clarke pumps available in our catalogue are submersible and known for their durability; they operate in dirty water—even water containing solids in suspension—as flood water undoubtedly will have. Now for the ingenious part: the pump has a float switch that enables it to operate automatically, whenever it detects a rise in the water level. So, if disaster strikes, this pump will be one step forward on the road to recovery.

    For more information on the kinds of pumps we sell, check out our article about it here.

    Keep the important belongings safe

    Expensive electrical gadgets, that handmade rug from overseas—any sentimental/irreplaceable belongings should be kept far from range of any floodwater; ideally upstairs, in waterproof cases, even in a different building. The plug sockets, if they aren’t already, should be relocated to higher ground.

    Prepare an emergency flood kit

    Ideally this should contain your ID, a change of clothes, any medication you should require, and some first-aid equipment—in addition to a list of useful contacts such as Floodline and your home insurance and policy number.  

    Be wary of the hidden costs for homeowners on a floodplain

    In addition to the already enormous cost of buying a home in Britain, an increasing number will require substantial investment into flood deterrents. Think, are you buying a home in a flood-prone area? Is it flood-resistant and, is it worth the price if not? It can cost anything up to £5,000 to resist quick, flash floods and this number can be expected to accumulate to as much as £40, 000 in the long term, in the more vulnerable flood hot spots. So think carefully before you commit.

    Do you live in a high-risk flood area? Read our blog here to find out, then take the appropriate measures.

  • How to create and maintain the perfect garden pond

    garden pond

    A pond is an attractive proposition for many homeowners. A body of water brings with it a burgeoning ecosystem of aquatic wildlife and vegetation, as well as aesthetic value. Despite the obvious advantages of having a garden pond, the effort required to actually build and maintain a thriving pond is an insurmountable stumbling block for many. Creating the perfect pond may not be as painstaking a task as you may have anticipated. With this quick guide as a head start, you may find it a great deal easier than expected.


    The construction aspect of installing a pond into your garden is far and away the most costly and arduous component of the whole endeavour. Before lining the pond, the turf itself has to be excavated to your desired shape and depth by hand - whether you choose to dig it yourself or hire someone else is completely up to you. From there, a pond filter has to be installed to keep the water clean. A not altogether essential but nevertheless significant step is to surround the pond with rocks, stones or slabs as both a practical and decorative addition.


    The type of wildlife you intend to attract to your pond will also dictate how you maintain it. Koi fish, while relatively hardy and resilient, require a finely tuned set of conditions in order to flourish. Neutral pH levels, excessive filtering and sterilisation of bacteria are all prerequisites for a koi pond.

    And while your instinct may agree to this in order to cultivate glistening crystal-clear waters, much of the wildlife typical of British ponds actually prefer to operate in much more congested waters full of vegetation. Tadpoles for example, depend on a bountiful source of algae as their primary food source. The Royal Horticultural Society recommends that only around 50% of surface water should be free from vegetation.


    Any plants that you choose to inhabit your pond serve a practical purpose as well as an ornamental one. Certain plant species will help oxygenate your pond and some will even attract other species and wildlife. Other pond plants with unassuming names like water fern and floating pennywort are actually invasive and can have a devastating impact on the surrounding ecosystem - be extremely careful which plant life you choose to introduce.


    Costs can vary wildly depending on the size of your pond and the type of life you want to live in it. Even within a single species, costs can differ dramatically from one purchase to another. Koi fish for example, a hugely popular pond species, can range in price from £10 to thousands and thousands; it all depends on your preferences.


    submersible dirty water pump

    Even the most unkempt garden pond requires a certain amount of maintenance. Thinning out overgrown plants and removing any debris that may accumulate in the water are minimum requirements for a healthy pond. A full and thorough overhaul in which a submersible dirty water pump is used to drain the pond is required once every five years.

  • Positive Displacement Pumps vs Centrifugal Pumps

    Whilst positive displacement pumps and centrifugal pumps are two disparate branches of pumps that are also two of the most commonly used, the differences between them are slight, making it tricky at times to decipher exactly which one should be used in which scenario. To establish the differences and similarities between the two, as well to clarify which pump is more cost-effective and which is best at handling high-viscosity fluids, we have put together this guide.

    What are the fundamental differences?

    Centrifugal pump Centrifugal pump

    Centrifugal pumps are rotodynamic, which means they work by constantly imparting energy to the liquid through the movement of a propeller, rotor or impeller. Centrifugal pumps are used more frequently than positive displacement pumps, and they owe this status to the simplicity of their design, which also makes them cheaper. With few moving parts, maintenance and repair costs are limited. They are also relatively compact, making them ideal in situations in which space is at a premium.

    Positive displacement pumps meanwhile are not rotodynamic, and rely on trapping on a fixed volume of liquid and forcing it through the pump’s discharge. They can be distinguished further from centrifugal pumps by the means by which they impart energy to the liquid. Rotary pumps work through rotation of the pump element, while reciprocating pumps work through a constant back-and- forth motion.

    How else do they differ?

    The simple structure of centrifugal pumps allows it to be easily replicated in a variety of different materials that cater to a number of different purposes. For example, plastic and cast iron replicas are used for less intensive applications whilst bronze and stainless steel editions are better equipped to cope with more corrosive fluids. The popularity of centrifugal pumps can also then be attributed to this unique kind of versatility.

    Positive displacement pumps operate at a slightly lower speed, they are superior in a number of ways.What separates positive displacement pumps from centrifugal pumps (and justifies the gulf in cost) is their ability to maintain their efficiency in spite of varying viscosity, pressure and flow. Their flow rate remains high thanks to their internal clearances.

    What are they used for?

    Centrifugal pumps are best suited to pumping low viscosity liquids at low pressure at a high flow rate.  When faced with a fluid with high viscosity, the flow rate of centrifugal pumps drops dramatically due to frictional losses within the pump and damage and cavitation can even occur. Similarly, if any variations in pressure arise, the performance of the pump will fall. For these reasons, centrifugal pumps are normally used in the transfer of water, or even thin fuels and chemicals.

    Positive displacement pumps' ability to keep a constant flow rate makes them far better suited to pumping fluids with higher viscosities than centrifugal pumps; making them ideal for pumping slurries, oils and sewage. The petrochemical and wastewater industries are popular destinations for positive displacement pumps. One widely respected and esteemed manufacturer of a form of positive displacement pump, progressive cavity pumps, is mono pumps.

    mono pumps Positive displacement pumps

  • The Wastewater Treatment Process

    Over time, the pressure imposed on water supplies in the UK by climate change has facilitated the construction of close to 9000 wastewater treatment plants. Slowly but surely, they are becoming an important and even ingrained part of how we as a society push back against global warming. Yet so few of us understand or are even aware of the process that transforms the wastewater that leaves our toilets, sinks and showers into potable drinking water. To provide you with a bare-bones look at the basics of the process, we have put together this summary of the role of the wastewater treatment plant.

    wilo pumps

    Screening process

    After wastewater is carried away from homes and, via a network of pipes and submersible wilo pumps, arrives at a wastewater treatment plant, it undergoes a screening process. To separate all of the biggest debris that so often accumulates, from the wastewater itself, the wastewater travels through a screen that essentially acts a sieve.  The type of screen used varies from plant to plant but the most commonly used screens include both coarse and fine screens, as well as the newer step screens.

    Primary treatment stage

    At the primary treatment stage, the mixture, newly relieved of its biggest and most easily extracted debris, is placed in a sedimentation tank. Within the settlement tanks, the heaviest material sinks to the bottom to form a layer of sludge. Large arms or scrapers then push this sludge towards the centre of the tank, where it can be disposed of or treated further, leaving a more refined fluid behind. The purpose of the primary treatment stage is to remove solids from wastewater in order to

    Secondary treatment stage

    The secondary treatment stage involves treating the wastewater to rid it of any remaining organic matter. This happens two ways - through the aeration of the wastewater and through the addition of bacteria. By pumping air into a large tank containing wastewater, bacteria are allowed to grow and thrive, where they break down any remaining nasty substances into harmless organic matter.

    Final treatment stage

    After undergoing this chemical treatment, wastewater is placed into a humus tank which separates the wastewater into its final constituents. Any remaining bacteria sinks to the bottom, forming sludge, which is then sent for secondary treatment, leaving clean water behind. Depending on which body of water the cleansed wastewater is sent to, an additional step is sometimes carried out - the remaining water can be filtered through a bed of sand to remove any resolute particles.

    Once the entire water reclamation process has been completed, the treated water can be sent to any number of different locations. The majority of treated wastewater in the UK goes back into the country’s streams and rivers and some is even discharged into the sea. Because treated water is subject to such rigorous testing by regulatory bodies, all reclaimed water bolsters the quality of water throughout the UK, not to mention availability.

  • The UK Locations Most At Risk of Flooding

    As global warming continues its march relatively unimpeded, sea levels and the incidence of tumultuous weather will continue to rise. And while many may assume that coastal regions of the UK are far and away the most susceptible to flooding, data collected by the Environment Agency actually shows that the network of rivers and tributaries that wind their way throughout Britain make inland areas just as vulnerable.

    Boston and Skegness

    It is however, a coastal region that is most in dangerous in terms of flooding. Boston and Skegness, both perched precariously on the Lincolnshire coast, are subject to frequent storm surges that plague that particular stretch of the east coast. When deep depressions track across the Atlantic Ocean (resulting in lower pressure and rising sea levels) winds push the surface waters forward as part of a process known as wind drift. When these depressions reach the North Sea, they are forced southwards. Because this water cannot escape through the Dover Strait, it accumulates in this region and causes sea levels to rise dangerously, afflicting the east coast in the process. Just earlier this month, over 3000 residents were forced to evacuate their homes in the face of warnings of gale force winds and high tides.


    Nottingham is perhaps the most populous area that is perpetually under threat of sustaining damages from flooding. The city has been associated with flooding throughout its history, so much so that indentations marking the height of its historic floods have been engraved into Trent Bridge since 1852, and had been marked into the Hethbeth Bridge before it. The concern over flooding is so dire that £1 million of funds have been invested into flood defences to protect the Mapperley Park region of Nottingham. Everything from flood-resistant doors to storm gullies is under consideration.

    Vale of Clwyd

    The low-lying nature of the Vale of Clwyd puts it in jeopardy of regular flooding. The Welsh region owes this unenviable status not only to how low-lying it is, but also to its proximity to both the River Clwyd and the Irish Sea. Any time flash floods are forecast, more than 137,000 properties are at risk of being enveloped by water. The floods that devastated the region in 2012 are just one example of the area being affected by flooding.


    lowara pumps uk

    The River Thames continually threatens to put the residents of Windsor at risk. The 5000 residents that call the river’s banks their home have experienced severe flooding numerous times over the course of the last decade - the worst of which was the floods of 2012. The majority of residents were affected and train lines were wrought with delays and cancellations.

    If you live in an area that poses a risk of flooding, it is well worth opting to buy from lowara pumps UK. With a wide range of drainage and sump pumps available, a Lowara pump is a dependable ally for anyone who is wary of flooding affecting their home.

  • The Importance of Centrifugal Pumps in Industry

    As the name suggests, a centrifugal pump uses centrifugal force to pump a liquid containing solids. Centrifugal force is generated by the rotation of the impeller, which causes the liquid to leave the impeller’s vanes at a higher velocity than it had when it entered. In turn, this outward flow creates a pressure differential. Pressure is lowest at the impeller eye, which allows more liquid to enter - resulting in a constant flow of liquid through the pump.

    What differentiates a self-priming centrifugal pump from a standard centrifugal pump is the ability to pump liquid without the pump casing being entirely filled with liquid - thanks to the inclusion of a partial vacuum that allows self-priming pumps to rid themselves of air. Both standard and self-priming centrifugal pumps are an integral part of the water desalination, mining and petrochemical industries amongst others.

    Water desalination plants

    Water desalination

    With the UN predicting that 14% of the global population will be suffering from water scarcity by 2025, water desalination plants are set to become more vital than ever. By separating dissolved salts and other minerals from otherwise unusable water, water desalination plants are able to recover potable water for the areas that need it most. And, although desalination methods vary dramatically (from nanofiltration to electrodialysis), what unites these processes is the inclusion of centrifugal pumps. More than capable of transporting solid-containing seawater efficiently, self-priming centrifugal pumps are especially popular with high capacity water desalination plants.

    Mining industry

    The mining industry is unconventional in that it uses centrifugal pumps in an altogether different manner to similar industries. In the context of mining, despite being the same mechanism structurally, a centrifugal pump is known as a froth pump, because of the product it is altered to produce. Mineral processing owes the separation of precious minerals from gangue and bitumen to the intervention of centrifugal pumps. As well as actually playing a part in processing the minerals themselves, centrifugal pumps are also used to transport the slurries and solid-containing fluids that accumulate during the mining process.

    Petrochemical plants

    The petrochemical industry is worth well over $500 billion, and it is also an industry with a heavy reliance on centrifugal pumps. Given not only the value of the petrochemical components at play, but also the very real danger of them igniting means that the robustness of the centrifugal pumps involved is of utmost importance. Consequently, the production of plastics, rubbers and dyes is indebted to the use of well-designed centrifugal pumps.

    varisco pumps

    If you are an organisation looking for a robust self-priming centrifugal pump you can rely on, then look no further than Varisco pumps. The Italian brand has been a world leading pump manufacturer for seven decades. What separates Varisco from their competitors, besides their wealth of experience, is their commitment to variety - without sacrificing quality. Both stainless steel and bronze centrifugal pumps are available for industrial use, as well as a range of different power options for each edition - ensuring that you will find a centrifugal pump that is ideal for your use.

  • Money-Saving Tips for Winter

    Winter is a time where we all get to relax more than we should, eat more than we should and spend more than we should. When it comes to spending money though, we want to be sure that it goes on gifts for our closest friends and family – not on mundane but essential updates to our home. Unfortunately, the festive period also brings with it some of the worst weather the year has to throw at us, making repairs to plumbing and heating apparatus all too common. To ensure none of this seasonal reaches you over the winter months, you may want to consider some of the following changes to keep your bank balance as healthy as possible.

    Shower pumps

    salamander shower pump

    Salamander are one of the leading pumps brands around, and from their base in the South East, they have been providing UK homes with the highest quality pumping products for years. A core part of their range that will guarantee you perfectly pressured showers in spite of any boiler problems that may arise during the colder months, is the salamander shower pump. A shower pump of this quality is as effective as they get, and will keep your water pressure intact without any of the associated extra cost that you might otherwise expect.

    Circulating pumps

    circulating pump

    Whilst you may not be familiar with circulating pumps, they are actually one of the most cost-effective heating products money can buy. By ensuring that hot water is distributed evenly throughout the home, any additional and unnecessary expense is circumvented. Not only does the efficiency of a circulating pump minimise the cost of your water bill, it also ensures that extra energy won't be expended heating up water that won’t be used - allowing you to rest assured that your actions aren’t taking a toll on the environment.

    Grey water recycling

    grey water recycling

    Similarly, a grey water pump is ideal not just for those of us who are desperate to safeguard the health of the planet for the foreseeable future; it is also perfect for those of us who are more conscious than ever of exactly how much money we are spending (which is especially true during the festive period). A grey water recycling pump achieves both of these things by repurposing all of the grey water that would otherwise go to waste (from your baths, showers, dishwashers and sinks) for use elsewhere in the home. Given that a grey water recycling system is more than capable of reducing water usage by up to 50%, the upfront investment is miniscule and one you should be certain of considering.

    Sump pumps

    sump pump

    The threat of flooding is never higher than over the bitterly cold and wet winter months - whether that is from a particularly heavy downpour or pipes frozen to the point of bursting. Fortunately, there is one simple step you can take to stave off costly water damage. Installing a sump pump provides a hardy barrier to flooding by automatically casting away any water that may accumulate in the home. Once again, it is an essential initial investment that will easily repay itself over time.

1-10 of 130

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. ...
  7. 13