WaterBoost- Slimline EXT
WaterBoost WB-EXT Slimline 500 Mini3 Variable Speed 2503210
- Established 1975
- Trusted by thousands of customers
The WaterBoost WB-EXT Slimline 500 Mini3 is a high-storage variable-speed water boosting system for 3–5 bedroom homes. A 500-litre WRAS-approved slimline tank (700mm dia × 1500mm high) pairs with the DAB Esybox Mini3 external variable speed pump, delivering 50 l/min at 3 bar with WiFi, DConnect app, and Google Home and Alexa voice control.
The Esybox Mini3 sits alongside the tank rather than inside it — keeping the pump fully accessible for servicing and maintenance at any time. The tank connects directly to the mains via the pre-fitted ¾” ball float valve, and the system arrives fully pre-built with no site assembly required.
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 Mini3 a 3-year warranty. Please contact us for delivery timescales.
WRAS tank & pump
Variable speed
5.5 bar max
Direct mains
5yr tank warranty
More about this product
The WaterBoost WB-EXT Slimline 500 Mini3 is the larger sibling of the WB-EXT 300 Mini3 — a complete, pre-built variable-speed boosting system for 3–5 bedroom homes with high daily demand or a slow-filling mains supply. A 500-litre WRAS-approved slimline tank (700mm dia × 1500mm high) pairs with the DAB Esybox Mini3 external variable speed pump, delivering 50 l/min at 3 bar and up to 5.5 bar maximum.
The Esybox Mini3 sits alongside the tank — fully accessible for servicing and maintenance at any time — running at a quiet 45 dB(A). WiFi via the DConnect app enables remote pressure monitoring and control, with Google Home and Alexa voice commands included. The mains connects directly via the pre-fitted ¾” ball float valve. Fully pre-built — no site assembly required.
Includes union connections, ¾” ball float valve, 600mm hose, and By-law 30 kit. 5-year tank warranty and 3-year DAB pump warranty. Please contact us for delivery timescales.
Two upright slimline systems in the 450–500L range. The WB-EXT 500 Mini3 has more storage, significantly higher flow, a higher max pressure, WiFi and voice control, variable speed, and named warranties. The Powertank SLIMLINE 450 Fixed offers Fluid Category 4 compliance for those who specifically require it.
WB-EXT 500 Mini3 — the better choice for most potable water boosting. More storage (500L vs 450L), higher flow (50 vs 40 l/min), higher max pressure (5.5 vs 3 bar), WiFi and voice control, variable speed energy efficiency, 45 dB(A) noise rating, and named 5yr tank and 3yr pump warranties.
Powertank SLIMLINE 450 Fixed — choose only if Fluid Category 4 compliance is a specific requirement for your installation. 450L, 40 l/min, fixed speed, 3L integral pressure vessel.
How is it delivered?
What is the difference between the 300L and 500L EXT Mini3 systems?
Why is the pump external rather than inside the tank?
How does the mains connection work?
I need 80 l/min — which system should I choose?
What warranties are included?
-
DAB Mini3 PDFDownload
-
Data Sheet 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.
You may also need
The WaterBoost WB-EXT Slimline 300 Mini3 is a variable-speed water boosting system combining a 300-litre WRAS-approved slimline tank (600mm dia × 1200mm high) with the…
The WaterBoost WB-INT Slimline 500 is a complete, pre-built variable-speed water boosting system for high-demand 3–5 bedroom homes. A 500-litre WRAS-approved upright slimline tank pairs…
The WaterBoost WB-Coffin 450 Mini3 is a compact, variable-speed water boosting system engineered to overcome low water pressure or restricted flow in domestic and light…
The WaterBoost WB-EXT Slimline 150 Mini3 is a compact, variable-speed water boosting system combining a 150-litre WRAS-approved slimline tank (600mm dia × 650mm high) with…
Frequently Asked Questions
Quick answers to common questions about the WaterBoost WB-EXT Slimline 500 Mini3 Variable Speed 2503210. 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.




