WaterBoost – CAT 5 range
WaterBoost CAT 5 WB-Coffin 340 Mini3 Variable Speed 2206210CT5
- Established 1975
- Trusted by thousands of customers
The WaterBoost WB-Coffin 340 Mini3 Cat 5 (Type AB Air Gap) is a complete variable-speed water boosting system that combines low-profile coffin storage with the highest level of backflow protection in common use. The Type AB air gap cistern protects the mains against fluids up to and including Fluid Category 5, making it suitable for commercial, healthcare, laboratory, agricultural and industrial premises where ordinary domestic protection is not enough.
The system pairs a 340-litre WRAS-approved Category 5 AB air gap coffin tank with the DAB Esybox Mini3 variable-speed pump, delivering 50 l/min at 3 bar and a maximum delivery pressure of 5.5 bar. The pump’s intelligent inverter adjusts continuously to match demand — constant pressure to multiple outlets, lower energy use than fixed-speed alternatives.
Tank dimensions 1500mm (L) × 600mm (W) × 630mm (H). Supplied with the float valve discharging above the air gap, weir overflow, ½” connection and 1″ brass outlet. All interconnecting pipework included as standard.
Type AB air gap
WiFi · Google · Alexa
WRAS tank & pump
630mm height
Pipework included
5.5 bar max
More about this product
The WaterBoost WB-Coffin 340 Mini3 Cat 5 is a complete, variable-speed water boosting system that delivers the highest level of backflow protection in common use in a low-profile coffin format. The Type AB air gap cistern stands just 630mm tall — fitting under stairs, inside cupboards, and in low-ceiling garages and plant rooms where an upright tank would not.
The mains supply discharges into the tank through a Type AB air gap — the float valve sits above an unobstructed air gap and the cistern carries a weir overflow sized to handle the full inlet flow. Because there is a permanent physical break between the incoming mains and the stored water, the system protects against fluids up to and including Fluid Category 5 — the most hazardous category.
The DAB Esybox Mini3 variable-speed pump draws from the tank, delivering a consistent 50 l/min at 3 bar. The intelligent inverter adjusts continuously to match demand, maintaining stable pressure across multiple outlets with low noise and reduced energy use. Supplied complete with weir overflow, ½” connection, 1″ brass outlet and all interconnecting pipework. WiFi via the DConnect app, Google Home and Alexa compatible. 3-year DAB warranty. Delivery typically 2 to 3 working days.
The Category 5 version shares the same pump, flow, pressure and smart features as the standard WB-Coffin 340 Mini3. The single difference — and the reason to choose it — is the level of backflow protection.
Which should I choose? Choose the Category 5 (Type AB air gap) version wherever a serious contamination risk exists or Category 5 is specified — commercial, healthcare, dental, laboratory, agricultural and industrial premises. For ordinary domestic installations the standard Cat 1–3 version is sufficient and more economical. Both share the same pump, performance and smart control.
How much does it cost and how is it delivered?
Please contact us via WhatsApp or phone for current pricing. Delivery is typically 2 to 3 working days.
What is a Type AB air gap and Category 5 protection?
A Type AB air gap is the highest level of backflow protection in common use. The tank’s float valve discharges above an unobstructed air gap into a cistern fitted with a weir (slot) overflow sized to handle the full inlet flow. Because there is a permanent physical break between the incoming mains and the stored water, contaminated water can never be drawn back into the public supply, whatever happens downstream. This protects against fluids up to and including Fluid Category 5 — the most hazardous category, covering serious health risks.
What is the difference between this and the standard WB-Coffin 340 Mini3?
Both are identical pump-and-tank packages built around the DAB Esybox Mini3 and a 630mm low-profile coffin tank — same flow, pressure, WiFi and warranty. The difference is backflow protection. The standard version uses a ball float valve giving Fluid Category 1–3 protection, suitable for ordinary domestic use. This version uses a Type AB air gap cistern (Cat 5) — the highest level of protection, for premises where a serious contamination risk exists or Category 5 is specified.
Why a coffin tank?
A coffin tank is a horizontal, low-profile rectangular tank. At just 630mm high, it fits under stairs, inside cupboards and in garages or plant rooms where the height available would prevent an upright tank from being installed. If height is not a constraint, an upright slimline system may offer a smaller floor footprint for the same capacity.
Is 340 litres enough storage?
For most 2–3 bathroom properties with a reasonable mains fill rate, 340 litres is more than adequate. Note that the working volume of an AB air gap cistern sits below the weir spillover level. For larger properties or higher simultaneous demand, the 500-litre option provides additional buffer.
Should I choose Mini3 or Esybox?
The Mini3 is the right choice for most 2–3 bathroom properties — compact, ultra-quiet (45 dB) and energy-efficient, delivering 50 l/min at 3 bar (70 l/min max). The Esybox delivers significantly higher performance — 80 l/min at 3 bar (120 l/min max) and 6 bar max pressure — for larger homes with 3+ bathrooms or light commercial premises with high simultaneous demand. Both are available with the Type AB air gap Cat 5 tank.
How does the WiFi work?
The DAB Esybox Mini3 connects to the DConnect app via built-in WiFi for remote pressure monitoring and control. It also works with Google Home and Amazon Alexa — “Hey Google, power shower” boosts pressure; “Hey Google, sleep mode” reduces it at night.
What warranty is included?
3 years DAB manufacturer warranty on the DAB Esybox Mini3 pump and 5 years on the tank when purchased from Anglian Pumping Services.
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Esybox Mini3 PDFDownload
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Data Sheet PDFDownload
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Manual 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 CAT 5 WB-Coffin 340 Mini3 Variable Speed 2206210CT5. 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.