Name: WaterBoost WB-EXT Slimline 300 Mini3 Variable Speed 2502210
Brand: WaterBoost
SKU: GROUP-slimline-1
Price: 816 GBP
Availability: InStock

WaterBoost WB-EXT Slimline 300 Mini3 Variable Speed 2502210

WaterBoost WB-EXT Slimline 300 Mini3 Variable Speed 2502210 - Image 3

WaterBoost WB-EXT Slimline 300 Mini3 Variable Speed 2502210 - Image 4

WaterBoost WB-EXT Slimline 300 Mini3 Variable Speed 2502210 - Image 5

WaterBoost WB-EXT Slimline 300 Mini3 Variable Speed 2502210 - Image 6

In stock

Established 1975
Trusted by thousands of customers

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 DAB Esybox Mini3 external variable speed pump. It delivers a reliable 50 l/min at 3 bar with WiFi, DConnect app, and Google Home and Alexa voice control — making it the best-value variable-speed option in the slimline range for 3–4 bedroom homes.

The Esybox Mini3 sits alongside the tank rather than inside it, providing easy access for servicing and maintenance. At 600mm diameter the tank fits through a standard doorway and can be installed under stairs, in a garage, or in a utility room. The mains connects directly via the pre-fitted ¾” ball float valve. Supplied fully pre-built with no site assembly required.

Includes 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.

50l/min

@ 3 bar

300L

Tank storage

45dB(A)

Ultra quiet

3yr

Pump warranty

WiFi · Google · Alexa
WRAS tank & pump
Variable speed
Fits through doorway
Pre-assembled
5yr tank warranty

Full Description

More about this product

Full Description

Product overview

The WaterBoost WB-EXT Slimline 300 Mini3 brings variable-speed performance, WiFi, and voice control to an upright slimline format that fits through a standard doorway — at a lower price than comparable fixed-speed alternatives. A 300-litre WRAS-approved slimline tank (600mm dia × 1200mm high) pairs with the DAB Esybox Mini3 external variable speed pump, delivering 50 l/min at 3 bar. Designed for 3–4 bedroom homes with poor pressure or restricted mains flow.

The Esybox Mini3 sits alongside the tank — not inside it — keeping the pump fully accessible for servicing or replacement at any time, and running at a whisper-quiet 45 dB(A). The mains connects directly via the pre-fitted ¾” ball float valve. Supplied fully pre-built — no site assembly needed. The 600mm diameter tank fits through a standard doorway for installation under stairs, in a garage, or utility room.

Includes union connections, ¾” ball float valve, 600mm connection hose, and By-law 30 kit. 5-year tank warranty and 3-year DAB pump warranty. Please contact us for delivery timescales.

50^l/min

Flow @ 3 bar

300^L

Tank storage

45^dB

Noise (1m)

5.5^bar

Max pressure

WRAS tank & pump · Direct mains · Pre-assembled

What’s included

DAB Esybox Mini3 pump

External variable speed pump — sits alongside the tank. 50 l/min @ 3 bar, 5.5 bar max, 45 dB(A), WiFi via DConnect app, Google Home, Alexa. Pre-fitted plug. 3-year DAB warranty.

300L slimline tank

WRAS-approved 300-litre upright slimline tank — 600mm dia × 1200mm high. Fits through a standard doorway. ¾” ball float valve, 600mm hose, 2× union connections, 1″ pre-fitted tank outlet, By-law 30 kit. 5-year warranty.

Key features

50 l/min @ 3 bar — variable speed

Higher flow than fixed-speed competitors (40 l/min) with automatic speed adjustment to match demand — energy-efficient and stable pressure.

WiFi and voice control

DConnect app, Google Home, and Alexa — remote monitoring, pressure control, and voice commands like “Hey Google, power shower.”

External pump — easy servicing

Mini3 sits alongside the tank — fully accessible for inspection or replacement without tank disturbance. Runs at 45 dB(A).

Fits through a standard doorway

600mm diameter × 1200mm high — passes through a standard UK doorway pre-assembled. Under stairs, garage, utility room.

Direct mains connection

Tank fills automatically via the pre-fitted ¾” ball float valve. Minimum 0.5 bar incoming pressure required.

WRAS approved — potable water

Both tank and pump carry WRAS approval — fully compliant for potable water use in the UK.

5yr tank + 3yr pump warranty

5-year warranty on the WRAS slimline tank and 3-year DAB warranty on the Esybox Mini3 pump.

Fully pre-built

Arrives ready to install — no site assembly. Includes union connections, ¾” ball float valve, 600mm hose, and By-law 30 kit.

Also available in 500L

The WB-EXT Slimline 500 Mini3 (£770 + VAT) provides 500L storage with the same external Mini3 pump for higher-demand properties.

Typical applications

3–4 bedroom homes

Strong all-round performance for multiple simultaneous outlets — 50 l/min @ 3 bar with variable speed efficiency.

New and existing properties

Passes through a standard doorway pre-assembled — easy to install in both new builds and existing properties without specialist access.

Where pump access matters

External pump layout means the Esybox Mini3 is always accessible for inspection, servicing, or replacement without disturbing the tank.

Under stairs, garage, utility room

600mm diameter and 1200mm tall — fits neatly in standard domestic spaces without structural alterations.

Slow or restricted mains supply

300L fills overnight as a buffer — ready for peak morning and evening demand even on a restricted or slow mains supply.

Smart home integration

WiFi, DConnect app, Google Home, and Alexa voice control for convenient, remote management of water pressure throughout the day.

Technical specifications

DAB Esybox Mini3 pump

Flow rate	50 l/min @ 3 bar
Max pressure	5.5 bar
Pump type	Variable speed — external
Noise	45 dB(A) at 1m
Connectivity	WiFi — DConnect, Google, Alexa
Supply	240V, 50Hz — pre-fitted plug
WRAS	Yes
Warranty	3 years (DAB)

Slimline tank

Capacity	300 litres
Dimensions (dia × H)	600mm × 1200mm
Mains inlet	Direct — ¾” BSP ball float valve
WRAS	Yes — WRAS-approved material
Assembly	Fully pre-built
Min inlet pressure	0.5 bar recommended
Warranty	5 years

How it compares

Three upright slimline systems in the 200–350L range. The WB-EXT 300 Mini3 is the cheapest, has the most storage, the highest flow, and adds variable speed and WiFi — at £680 compared to £744.60 and £775 for the fixed-speed alternatives. The Powertank options offer Fluid Category 4 compliance for those who specifically require it.

Feature	WB-EXT 300 Mini3 this product	Powertank SLIMLINE 200 Fixed	Powertank SLIMLINE 350 Fixed
Tank capacity	300L WRAS upright	200L WRAS upright	350L WRAS upright
Pump type	Variable speed (Mini3 — external)	Fixed speed (Presflo Multi — external)	Fixed speed (Presflo Multi — external)
Flow rate @ 3 bar	50 l/min	40 l/min	40 l/min
Max pressure	5.5 bar	3 bar	3 bar
WiFi / app	Yes — DConnect, Google, Alexa	No	No
Noise	45 dB(A)	Not stated	Not stated
Fluid Category	Cat 1–3 (potable)	Up to Cat 4	Up to Cat 4
Tank warranty	5 years	Contact us	Contact us
Pump warranty	3 years (DAB)	Contact us	Contact us
Price (ex VAT)	£680.00	£744.60	£775.00

Which should I choose?
WB-EXT 300 Mini3 — the outstanding choice at £680 + VAT. Lower price than both Powertank alternatives, more storage than the 200 (300L vs 200L), higher flow (50 vs 40 l/min), 5.5 bar max, WiFi and voice control, variable speed, named 5yr tank and 3yr pump warranties. The right choice for potable water boosting in 3–4 bedroom homes.
Powertank SLIMLINE 200 Fixed — choose only if Fluid Category 4 compliance is a firm requirement. 200L, 40 l/min. £744.60 + VAT.
Powertank SLIMLINE 350 Fixed — choose for Fluid Category 4 with more storage (350L). Still 40 l/min, fixed speed, no WiFi, at £775 — more expensive than the WB-EXT 300 Mini3 with lower performance. Choose only if Cat 4 is a specific requirement.

Frequently asked questions

How much does it cost and how is it delivered?

£680.00 + VAT (£816.00 inc VAT). Please contact us via WhatsApp or phone for delivery timescales on this product.

Why is the pump external rather than inside the tank?

The “EXT” in the product name means the DAB Esybox Mini3 is mounted alongside the tank, not submerged inside it. This keeps the full Mini3 pump unit fully accessible at all times for inspection, servicing, or replacement — without any need to open or disturb the tank. It also means the pump can benefit from all the Esybox Mini3’s features including WiFi and variable speed without the cost of an internal variable speed design.

How does the mains connection work?

The mains supply connects directly to the tank via the pre-fitted ¾” ball float valve. The tank fills automatically. The Esybox Mini3 draws from the tank via the 600mm connection hose and boosts pressure throughout the property. A minimum of 0.5 bar incoming pressure is required.

Is there a 500L version in the same EXT format?

Yes — the WB-EXT Slimline 500 Mini3 (£770 + VAT) uses the same external Esybox Mini3 pump with a larger 500L tank (700mm dia × 1500mm high). For 80 l/min, the WB-EXT Slimline 500 Esybox (£1,084 + VAT) steps up to the full DAB Esybox pump.

How does the WiFi control work?

The Esybox Mini3 connects to the DConnect app via built-in WiFi for remote monitoring and pressure adjustment. It integrates with Google Home and Amazon Alexa — “Hey Google, power shower” to boost pressure, or “Hey Google, sleep mode” to quieten it at night.

What warranties are included?

5 years on the WRAS slimline tank and 3 years DAB warranty on the Esybox Mini3 pump, when purchased from Anglian Pumping Services.

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Delivery Information

Standard delivery:

Standard delivery is free for all orders except for some low cost/low margin items where standard delivery is £6.75. Some difficult to transport goods also have a varying carriage charge applied.

Please contact us for the estimated standard delivery times of the products that we have in stock, by dropping us a message on our Whatsapp or Live chat.

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 £15.00 + 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.

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