WaterBoost- Slimline EXT
The WaterBoost Slimline EXT range is a cost-effective, space-saving solution to low water pressure or flow, with the pump mounted externally — neatly beside the storage tank — for easy access and straightforward maintenance. It arrives prebuilt and ready to use, ideal for the customer looking to save on installation cost without compromising on quality.
Powered by a DAB variable-speed pump — the best-selling Mini3 or the full-size Esybox — the range delivers up to 120 l/min and 6.5 bar. At 600–700 mm wide it fits through a standard doorway and tucks neatly under the stairs, in a garage or a utility room — ideal for 3–5 bedroom homes with poor pressure and limited floor space.
Why choose Slimline EXT?
Key specifications
| Pump options | DAB Esybox Pop — up to 65 l/min · 3.2 bar (150 L) DAB Mini3 — up to 80 l/min · 5.5 bar (150 / 300 / 500 L) DAB Esybox — up to 120 l/min · 6.5 bar (300 / 500 L) |
| Tank sizes | 150 / 300 / 500 L · WRAS approved |
| Pump mounting | External, beside the tank — easy access & maintenance |
| Width | 600 mm (700 mm on the 500 L) — fits through a standard doorway |
| Supply | Prebuilt — ready to use |
| Siting | Under stairs, garage or utility room |
| Best for | 3–5 bedroom homes with poor pressure and limited floor space |
For easy-access maintenance and a prebuilt, ready-to-use system that fits indoors, the WaterBoost Slimline EXT range is a cost-effective answer to low pressure and flow. Choose your model below.
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6 products
The WaterBoost WB-EXT Slimline 150 with DAB Esybox Pop is a compact, variable-speed water boosting system combining a 150-litre WRAS-approved slimline tank (600mm dia ×…
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…
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-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 ×…
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 ×…
The WaterBoost WB-EXT Slimline 500 Esybox is a high-performance, high-storage variable-speed boosting system for 3–5 bedroom homes. A 500-litre WRAS-approved slimline tank (700mm dia ×…
Frequently Asked Questions
Quick answers to common questions about the WaterBoost- Slimline EXT. 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.