Site Drainage Pump Kit | EVAK Drainox 400 & 750

Site drainage pump kit for excavations, footings and site water The workhorse of the range, in two sizes, with the hose already matched to it. This FPS Engineered™ kit pairs an EVAK Drainox with 20m of 50mm layflat hose and a stainless-steel hose clip. The pump arrives with its own 2 inch hose tail, so the kit connects with nothing else to buy. The Drainox is built for arduous site work: a stainless steel strainer base, cover and handle over an FC20 cast iron pump housing, with an abrasion-resistant Hytrel vortex impeller that keeps working in water carrying grit, silt and suspended solids. Choose the pump to match how high you need to lift the water. That decision is set out below. Part of our wider site drainage, dewatering and EVAK ranges. Which pump: 400 or 750? Both kits are identical apart from the pump. The difference is what happens as the lift increases. Every centrifugal pump delivers less as it has to push water higher, and each has a point where it effectively maxs out. For the Drainox 400 that arrives at around 8 to 10 metres. The 750 has four more metres of head in reserve, so at the lifts where the 400 is struggling it is still working normally. Measure from the water surface to the point where your hose will discharge. That figure, is what should decide it. Uphill lift Drainox 400 Drainox 750 Difference 2 m 190 L/min 257 L/min 35% more 4 m 167 L/min 236 L/min 41% more 6 m 141 L/min 213 L/min 51% more 8 m 109 L/min 188 L/min 72% more 10 m 63 L/min 158 L/min Two and a half times Choose the Drainox 400 for lifts up to about 6m, which covers most footings, trenches and surface water on a site. It is the better value and it will not be working hard. Choose the Drainox 750 if you are lifting higher than that, running the discharge a long way as well as up, working a deep excavation or basement dig, or dealing with water arriving faster than the smaller pump can clear it. At a glance 190 to 257 litres per minute: Through the 20m of layflat supplied, at a typical 2m lift, depending on the pump chosen. Built for site use: Stainless steel outer cover, handle and strainer base over a cast iron pump housing. Hytrel vortex impeller: Highly abrasion resistant, which is what grit-laden water demands. Automatic operation: Starts and stops with the water, so it can be left in an excavation working. Friction almost irrelevant: At 50mm bore the full 20m run costs under 1m of head, so the pump's capability goes into lift rather than the hose. What's included 1 × EVAK Drainox automatic submersible site drainage pump, 400 or 750 as selected 1 × 2 inch, 50mm hose tail, supplied with the pump 1 × 20 m length of 50mm layflat hose 1 × 40 to 60mm stainless-steel hose clip How the kit connects The Drainox has a 2 inch BSP female outlet with the hose tail supplied. Slide the layflat over the tail and tighten the clip. That is the whole assembly. Lay the layflat out before switching on and check it is not doubled back on itself. Layflat firms up under pressure but will hold a kink if it starts folded. Why 20 metres, and why there is no length to choose Because at 50 mm bore, hose length barely changes the answer. Friction loss depends heavily on bore. On a narrow hose every extra metre costs real flow, which is why our 19 mm garden kits let you pick a length. At 50mm, doubling the run from 10m to 20m costs around 3 percent, which is inside the margin of error on the figure itself. So rather than ask you to choose between options that perform the same, we supply the longer one. Running 10m short stops a job. Running 10m long costs nothing you would notice, and 20m gets water clear of an excavation, over a kerb or out to a road gully on most sites. Expected performance Estimated flow through the supplied 20m of 50mm layflat, discharging freely. Lift is measured from the water surface to the point where the hose discharges. Uphill lift Typical situation Drainox 400 Drainox 750 2 m Shallow footings, ground level discharge 190 L/min, 11,400 per hour 257 L/min, 15,400 per hour 4 m Excavation up to a kerb or gully 167 L/min, 10,000 per hour 236 L/min, 14,200 per hour 6 m Deep excavation or basement slab 141 L/min, 8,500 per hour 213 L/min, 12,800 per hour 8 m Deep dig with a high discharge point 109 L/min, 6,500 per hour 188 L/min, 11,300 per hour 10 m At or near the 400's limit 63 L/min, 3,800 per hour 158 L/min, 9,500 per hour Estimated using the published Drainox curves and Hazen-Williams friction for 50 mm bore. Friction across the full 20 m run is under 1 m of head, so almost all the pump's capability goes into lift rather than being lost in the hose. At 167 litres per minute a 3 m × 2 m excavation holding a metre of water, around 6,000 litres, clears in roughly 36 minutes with the 400 and 25 minutes with the 750. Work out a specific run with our pump performance calculator. Technical specification Specification Drainox 400 Drainox 750 Maximum flow 225 litres per minute 300 litres per minute Maximum head 11 metres 15 metres Motor power 400 W, 0.5 HP 750 W, 1 HP Current at 230 V 4 A 5.4 A Weight 13 kg 16 kg Operation Automatic, 230V single phase Free passage 5 mm Outlet 2 inch, 50 mm BSP female, hose tail supplied Motor speed 2,850 rpm Impeller Hytrel vortex, highly abrasion resistant Construction Stainless steel strainer base, outer cover and handle; FC20 cast iron pump housing; ADC12 alloy motor housing and seal casing Seals Double mechanical seal in oil chamber, SIC/SIC Motor protection Auto-reset thermal protector Trenchman or Drainox? Both are EVAK contractor site drainage pumps, the difference is not really flow or head, it is what the pump is built to do. Drainox Trenchman Built for Longer-term dewatering and harder-wearing installations Silty water and settled sediment Agitator No Yes, keeps solids in suspension Free passage 5 mm 15 mm Construction Stainless steel vortex Cast iron and alloy, Hytrel-coated impeller Control options Manual, automatic or 400 V three phase Automatic only Put simply: Drainox where the pump has to stay in. Trenchman where the silt has to come out. If the water has settled and gone thick at the bottom, a Drainox will pump the clear water off the top and leave the silt behind. That is the job the Trenchman kit exists for. What can I use it for? Construction site drainage and dewatering Civil engineering, mining and tunnelling Pumping out excavations, trenches and flooded areas Public works and contractor hire fleets Flood response and emergency dewatering Long-term dewatering where abrasive water is involved Installation and use Set the pump on a firm level base at the lowest point, clear of loose silt and debris. Run the hose to an approved discharge point and avoid tight bends, which restrict flow more than length does. Keep the plug and connections dry and above any possible water level, and never lift the pump by its cable. Check the intake and discharge periodically. A pump nobody inspects is not reliable protection. Flush through with clean water at the end of an abrasive job. Water quality limits Clean and dirty water, solids to 5 mm. The Drainox handles the grit and sand that comes with site water, but it is not a solids-handling or sewage pump. Not for foul water, sewage or salt water. Where the water carries settled silt and fines, use a pump with an agitator instead. Frequently asked questions Should I choose the 400 or the 750? The 400 if you are lifting up to about 6m, which covers most site work, because it is better value and will not be straining. The 750 if you are lifting higher, running a long discharge as well as a high one, or if water arrives faster than the 400 clears it. At 10 m of lift the 750 moves two and a half times as much. Is the kit the same apart from the pump? Yes. Both come with 20m of 50mm layflat hose and a stainless-steel clip, and both pumps supply their own 2 inch hose tail. Only the pump changes. Drainox or Trenchman? Drainox for a stainless steel vortex pump suited to longer-term dewatering and harder-wearing installations. Trenchman where the water is silty and sediment settles, because its built-in agitator keeps solids in suspension and it passes 15 mm rather than 5 mm. Do I need to buy a hose tail? No. The Drainox comes with its own 2 inch hose tail, so the layflat goes straight on with the supplied clip. Why is there no choice of hose length? Because at 50mm bore it would not change anything. Doubling from 10m to 20m costs around 3 percent of the flow, which is smaller than the margin of error on the estimate, so we supply the longer one. Will it clear a floor completely? No, and it is not meant to. A drainage pump needs a working depth of water and leaves a layer behind. For taking a floor down to a millimetre or two you want a residue or puddle pump, such as the EVAK Residox. Can I leave it in an excavation? Yes, that is what automatic operation is for. Keep the pump clear of loose silt, use an RCD-protected supply, and keep the plug dry and above any possible water level. Are 110 V or three-phase versions available? Yes. The Drainox range includes 110 V in manual or automatic and 400 V three phase in manual.