WaterBoost- Slimline EXT
WaterBoost WB-EXT Slimline 300 Esybox Variable Speed 2502110
- Established 1975
- Trusted by thousands of customers
The WaterBoost WB-EXT Slimline 300 Esybox is a high-performance variable-speed boosting system for 3–4 bedroom homes combining a 300-litre WRAS-approved slimline tank (600mm dia × 1200mm high) with the DAB Esybox external variable speed pump. Delivering 80 l/min at 3 bar — with WiFi, DConnect app, H2D technology, Google Home and Alexa voice control — it is the most capable system in the WB-EXT slimline range.
The Esybox sits alongside the tank rather than inside it, keeping the pump fully accessible for servicing at any time. Running at just 43 dB(A), it is exceptionally quiet for an 80 l/min pump. The tank connects directly to the mains via the pre-fitted ¾” ball float valve. Fully pre-built — no site assembly required. At 600mm diameter, the tank fits through a standard doorway.
Supplied with union connections, ¾” ball float valve, 600mm hose, and By-law 30 kit. The tank carries a 5-year warranty and the DAB Esybox a 3-year warranty. Please contact us for delivery timescales.
WRAS tank & pump
6.5 bar max
External pump
Pre-assembled
5yr tank warranty
More about this product
The WaterBoost WB-EXT Slimline 300 Esybox is the highest-performing system in the WB-EXT slimline range. A 300-litre WRAS-approved slimline tank (600mm dia × 1200mm high) pairs with the DAB Esybox external variable speed pump, delivering 80 l/min at 3 bar and up to 6.5 bar maximum. Designed for 3–4 bedroom homes with demanding simultaneous water use and poor mains pressure.
The Esybox sits alongside the tank for full pump accessibility at all times — running at 43 dB(A), an exceptionally low noise level for an 80 l/min system. WiFi via the DConnect app and H2D technology enable remote monitoring and intelligent pressure management. Google Home and Alexa voice control included. The mains connects directly via the pre-fitted ¾” ball float valve. Fully pre-built — no site assembly required. The 600mm tank fits through a standard doorway.
Supplied with union connections, ¾” ball float valve, 600mm hose, and By-law 30 kit. 5-year tank warranty and 3-year DAB Esybox warranty. Please contact us for delivery timescales.
Three 80 l/min boosting systems with DAB Esybox-class performance. All feature variable speed and WiFi. The WB-EXT 300 Esybox combines WRAS confirmation on both tank and pump with a standard doorway-width tank and 6.5 bar maximum. The Powertank offers Fluid Category 4 and more storage. The DAB Esytank is a purpose-built DAB integrated system with 275L of useable storage.
WB-EXT 300 Esybox — the most complete specification of the three. The same DAB Esybox pump as the Esytank system, with 300L WRAS-confirmed storage, 6.5 bar max, 43 dB(A), WiFi and voice control, and named 5yr tank and 3yr pump warranties. Fits through a standard doorway. The right choice for most potable water boosting applications.
Powertank SLIMLINE 350 Variable — choose for Fluid Category 4 compliance with 350L storage. Note: 80 l/min but 3 bar max (not 6.5), and no WiFi.
DAB Esytank 300 with Esybox — the same Esybox pump in DAB’s own purpose-built integrated system. 275L useable storage (slightly less than the WB-EXT’s 300L). WRAS status not stated on product page. Choose if you specifically want the pure DAB Esytank ecosystem — for example, to link additional Esytank storage units using the DAB coupling kit.
How is it delivered?
What is the difference between this and the WB-EXT 300 Mini3?
What is H2D technology?
How does the mains connection work?
Is there a 500L version with the Esybox?
What warranties are included?
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Data Sheet PDFDownload
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Esybox Tech PDFDownload
Standard delivery:
Standard delivery is free on most orders. Some items may incur a delivery charge depending on weight, size or value. Any applicable charge will be displayed at checkout.
Deliveries will typically be made between 7am and 6pm, Monday to Friday (excluding public holidays).
Next day delivery:
Next working day delivery is available for a £16.50 + VAT delivery charge.
Orders must be placed before 12 noon to qualify for next working day delivery. Orders placed after 12 noon on Thursday but before noon on Friday will be delivered the following Monday. Orders placed after 12 noon on Friday will be delivered on Tuesday.
Pallet/Large/Difficult items:
Some large, heavy or difficult to transport items may incur an additional delivery charge. Please contact us for a delivery quote before ordering.
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Frequently Asked Questions
Quick answers to common questions about the WaterBoost WB-EXT Slimline 300 Esybox Variable Speed 2502110. For technical specifications, see the product details above; for sizing or installation advice, contact our team. If you have any other questions, we're happy to help.
What is a mains pressure boosting system?
A mains pressure boosting system increases the pressure and flow of water from the incoming mains supply into a property. It typically combines a pump and a storage or expansion tank, drawing water from the mains and delivering it to taps, showers and appliances at a stronger, more consistent pressure. They are used where the incoming mains is too weak to serve modern outlets reliably.
When do I need a mains booster pump?
You normally need a mains booster if static mains pressure is below 1.5 to 2 bar, if showers run weakly when other taps are open, or if combi boilers struggle to deliver hot water. Anglian Pumping recommends checking static pressure at the stop tap before specifying a system, then choosing a model rated for the number of bathrooms and outlets in the property.
What size mains booster do I need for my home?
Sizing depends on the number of bathrooms, the type of fittings and the static mains pressure. As a guide, a 1 to 2 bathroom property with combi boiler or single shower often needs 1.6 to 3 bar boost. A 2 to 3 bathroom property typically needs 3 to 4.5 bar with an integral break tank. Larger homes need a tank-and-pump system such as the DAB Esybox with Esytank or a Powertank set.
What is a water booster pump?
A water booster pump increases the pressure of an existing water supply to give stronger flow at taps, showers and appliances. It can be a small inline pump fitted to the incoming mains, or a larger pump and tank set that draws from a break tank to feed the whole house. Boosters do not create water – they raise the pressure of the water already coming in.
What is the difference between an inline booster and a tank-and-pump booster?
An inline booster connects straight onto the incoming mains and is limited to 12 litres per minute under UK water regulations – examples include the Salamander HomeBoost and WaterBoost WB-Compact. A tank-and-pump booster, such as the Grundfos Home Booster or DAB Esybox with Esytank, draws from a break tank and can deliver much higher flow rates for larger homes with multiple bathrooms.
What is a variable speed booster pump?
A variable speed booster uses an inverter to adjust pump speed in real time to match demand. It maintains constant pressure as outlets open and close, runs more quietly than a fixed-speed pump and typically saves up to 50 per cent of the energy a fixed-speed equivalent would use. The DAB Esybox, DAB Esybox Mini 3 and Grundfos Scala2 are common variable speed examples.