WaterBoost ATX Whole-House Mains Pressure Booster
WaterBoost ATX-450 PURE Twin Whole House Mains Pressure Booster
- Established 1975
- Trusted by thousands of customers
The WaterBoost ATX-450 Twin Pure is the highest-capacity Pure system in the range, pairing two 450-litre Flow-Thru™ anti-Legionella vessels with a single variable speed pump — connecting directly to the incoming cold water mains. Patented scoops and water vanes recirculate both vessels continuously, so the water in your home stays as fresh as the day it arrived. No break tank, no overflow, just two water connections required.
Peak burst flow reaches up to 140 l/min, with 60 l/min sustained for up to 11 minutes — before settling to a continuous boosted flow until the vessels recharge. The twin-vessel arrangement provides 540 litres of useable working capacity — double the single ATX-450 Pure. Variable speed inverter technology means the pump only generates the pressure your mains can’t already deliver, at a quiet 40 dB(A). WiFi via the H2D App enables remote monitoring and control. A mains bypass fits in seconds using 2 clips.
Twin Flow-Thru anti-Legionella vessels — total recirculation, no stagnation, the freshest water quality possible. Completely maintenance free. Ideal for high-occupancy properties, large homes, HMOs, hotels, care, hospitality and healthcare under a Legionella duty. 5-year tank warranty, 3-year pump warranty. Need less capacity? See the single-vessel ATX-450 Pure.
3yr pump
Anti-Legionella
Freshest water
WRAS approved
Zero maintenance
Sealed — no air contact
Twin Flow-Thru
Variable speed
900L · 540L useable
No overflow
Dry run protection
Bypass fits with 2 clips
More about this product
3yr pump
What is the ATX-450 Twin Pure?
The WaterBoost ATX-450 Twin Pure is the highest-capacity Pure system in the WaterBoost range — engineered for properties where a single Pure cannot keep up. It connects directly to your incoming cold water mains, combining two 450-litre Flow-Thru™ anti-Legionella vessels with a single variable speed pump, automatically boosting both pressure and flow throughout the property the moment a tap or shower is opened. No break tank, no overflow arrangement, just two water connections required.
The twin-vessel design doubles the stored capacity over the single ATX-450 Pure — providing 540 litres of useable working capacity — while sharing a single high-performance variable speed pump for delivery. The result is a sustained boosted flow of 60 l/min for up to 11 minutes, with a peak burst flow at the moment of demand reaching up to 140 l/min. Sufficient for five or more showers running simultaneously, or for buildings with sustained multi-outlet demand.
Both vessels feature the patented internal scoop and water vane that force fresh water through the chamber every time the system runs, so the water in your home stays as fresh as the day it arrived — with no stagnation, no dead volume, no static stored water. Variable speed inverter technology means the pump only generates the pressure your mains can’t already provide, at a quiet 40 dB(A), with WiFi monitoring via the H2D App.
Why twin vessels?
A single Pure ATX-450 is a high-capacity system for most homes. The Twin Pure is specified where peak flow, sustained duration, or simultaneous-outlet demand goes beyond what a single vessel can meet — without moving to a tank-and-pump break tank installation.
| Performance | ATX-450 Pure | ATX-450 Twin Pure |
|---|---|---|
| Peak burst flow | Up to 80 l/min | Up to 140 l/min |
| Sustained boosted flow | 36 l/min for 11 min | 60 l/min for 11 min |
| Useable working capacity | 270 litres | 540 litres |
| Vessels | 1 × 450L Flow-Thru | 2 × 450L Flow-Thru |
| Pump | Single variable speed | Single variable speed |
Energy efficiency — only boosts what your mains can’t deliver
The variable speed pump continuously measures incoming mains pressure and adjusts its output to produce only the shortfall. If your mains delivers 1 bar and your target is 3 bar, the pump generates 2 bar. If your mains delivers 2 bar, the pump generates 1 bar. No wasted energy, no fixed worst-case output — even with twice the storage capacity behind it.
This is a fundamental advantage over water storage tank boosters, which run at the same full output regardless of what the mains already provides. Running costs with the Twin Pure reflect exactly what is needed — nothing more.
Freshest water — twin Flow-Thru anti-Legionella recirculation
Stagnation is the enemy of stored water. In a standard sealed accumulator the deepest water in the diaphragm can sit undisturbed for long periods. The patented Flow-Thru design removes that risk: every time water moves through the system, an internal scoop diverts it up into the chamber and a water vane drives total turnover. In the Twin Pure, both vessels recirculate — so even at twice the storage capacity, no part of the system holds static water.
At the heart of each vessel is the patented CAD-2 controlled-action diaphragm. Its steel clench ring regulates membrane movement and keeps the diaphragm off the tank wall for a long, reliable service life, and the air-valve cap is sealed with closed-cell foam for a leak-free pre-charge. The Flow-Thru series conforms to European and UK recommendations for the elimination of stored-water stagnation.
Incoming system water is diverted up into each tank chamber rather than parking at the inlet.
The patented water vanes drive full recirculation across both vessels — no dead volume, no stagnant pockets.
Continuously turned-over water leaves the manifold to the property at high boosted flow.
Anti-Legionella by design — on twin vessels. Both Flow-Thru vessels constantly recirculate their full contents, eliminating the static, stagnant volume found in conventional stored-water systems — the freshest water quality possible at the highest capacity. WRAS approved for use with potable water.
How it compares — hygiene by design
Every WaterBoost booster is a sealed, pressurised system and already beats open storage on hygiene. The Twin Pure delivers active recirculation across both vessels — the right choice wherever freshness, demonstrable water turnover, or sustained high-flow capacity matters.
| Hygiene credential | Open break tank | Standard ATX (sealed) | ATX-450 Twin Pure |
|---|---|---|---|
| No open water surface | ✗ Exposed | ✓ Sealed | ✓ Sealed |
| No overflow / hygiene risk point | ✗ Required | ✓ None | ✓ None |
| No static / stagnant stored volume | ✗ Sits static | − Reduced | ✓ Total recirculation ×2 |
| Active anti-Legionella turnover | ✗ | − | ✓ By design |
| Constant fresh-water turnover | ✗ | − | ✓ Across both vessels |
| Routine tank cleaning required | ✗ Yes | ✓ No | ✓ No |
The Twin Pure is specified wherever the freshest possible water, a documented Legionella control regime, or sustained high-capacity boosted flow is the priority.
Zero maintenance — fit it and forget it
The ATX-450 Twin Pure is a completely maintenance-free system. There are no consumable parts, no filters to replace, no annual service requirements and no engineer visits needed. The sealed, twin-recirculating design removes the hygiene maintenance obligations of open storage and leaves no static volume to manage, while the built-in anti-seize exercise function and dry run protection mean the system manages its own long-term health automatically — across both vessels.
What happens after installation
| Day 1 — Installation | Two water connections. Twin vessels and pump installed and commissioned. That’s it. |
| Year 1 — Nothing | No service visit. No filter change. No tank clean. Both Flow-Thru vessels keep the water fresh; system self-monitors via app. |
| Year 2 — Nothing | Anti-seize function runs automatically during low-demand periods. No action required. |
| Years 3 & 4 — Nothing | Pump warranty active. Dry run protection monitoring. Still no maintenance. |
| Year 5 — Warranty | 5-year tank warranty still in force across both vessels. System continues to operate without scheduled maintenance. |
⚡
30-second pump swap — unique dock system
If a pump replacement is ever needed, the ATX dock system allows the pump unit to be removed and replaced in under 30 seconds using two clips — no draining, no tools, no plumber required. The built-in bypass keeps the property on mains supply throughout.
How it works — two-phase operation, twin storage
The Twin Pure stores a ready supply of pressurised water across two manifolded 450-litre Flow-Thru vessels. When demand occurs, it delivers instant high-flow boosted water immediately, then continues at a sustained flow once the stored volume is used, before recharging automatically — with the stored water continuously recirculated across both vessels throughout.
Phase 1 — Stored volume
Instant high-flow boost
60 l/min
sustained — for up to 11 minutes
Delivered from the two pre-charged Flow-Thru vessels. Peak burst flow reaches up to 140 l/min. Suited to five or more showers running simultaneously or sustained high-demand whole-property use.
Phase 2 — Continuous mains
Sustained boosted flow
12 l/min
at 3 bar — continuous
Once stored volume is exhausted, the system continues boosting from mains. Both vessels recharge automatically when demand stops.
Technical specifications
| Brand / Model | WaterBoost — ATX-450 Twin Pure |
| System type | Twin-vessel integrated accumulator booster — direct mains |
| Vessels | 2 × Flow-Thru™ anti-Legionella, steel (GFU-450LV) — manifolded — patented recirculation + CAD-2 diaphragm |
| Water connections | 2 — inlet & outlet · 1¼” BSP outlet (through-flow vessels) |
| Accumulator capacity | 900 litres total (2 × 450L) · 540 litres useable working capacity |
| Peak burst flow | Up to 140 l/min |
| Sustained boosted flow | 60 l/min for up to 11 minutes |
| Continuous flow (post-discharge) | 12 l/min at 3 bar |
| Max pressure | 3.2 bar (vessels rated to 8.6 bar) |
| Pump type | Single variable speed inverter pump (shared across both vessels) |
| Noise level | 40 dB(A) |
| WiFi / connectivity | Yes — H2D App + on-unit HMI display |
| Hygiene | Sealed pressurised circuit + twin Flow-Thru recirculation — anti-Legionella by design |
| Vessel dimensions (each) | 1537 mm (H) × 660 mm dia · ~70 kg empty · ~340 kg filled. [Overall height with controller — confirm] |
| In-service weight | ~690 kg total (filled, both vessels) — confirm floor loading |
| Dry run protection | Yes — built in |
| Anti-seize exercise function | Yes — automatic |
| Maintenance bypass | Fitted in under 30 seconds using 2 clips |
| WRAS approved | Yes |
| Maintenance required | None — completely maintenance free |
| Warranty | 5-year tank · 3-year pump |
| Suited to | High-occupancy properties, large homes, HMOs, hotels, B&Bs, care, hospitality, healthcare, education · 5+ bed & high simultaneous-demand buildings |
Flow rates are dependent on incoming mains supply. Continuous flow of 12 l/min applies after stored volume is exhausted.
Frequently asked questions
What makes the Twin Pure different from the single ATX-450 Pure?
The Twin Pure uses two 450-litre Flow-Thru vessels on a single variable speed pump — doubling the useable working capacity to 540 litres, raising peak burst flow to 140 l/min, and sustaining 60 l/min for up to 11 minutes (vs 36 l/min on the single Pure). Both vessels recirculate, so anti-Legionella performance scales with capacity.
Why one pump for two vessels?
The vessels are the storage; the pump is the delivery. A single high-performance variable speed pump draws from both manifolded vessels and delivers the boosted output, which keeps installation, electrical requirement, footprint, and capital cost lower than a twin-pump arrangement — while still providing 540 litres of useable Flow-Thru capacity behind it.
Will the water really stay fresh across both vessels?
Yes. Both vessels are Flow-Thru — each has its own internal scoop and water vane forcing constant turnover during normal use. There is no part of the twin system where water sits static.
Does it help with Legionella risk assessments?
It supports your control measures — a sealed circuit with no open surface, no overflow, and continuous recirculation across both vessels rather than static storage. It does not replace a competent Legionella risk assessment, which remains the duty-holder’s responsibility under ACoP L8 / HSG274.
What does installation look like with two vessels?
Both vessels are manifolded behind the single pump assembly — the property still sees just two water connections (inlet and outlet). Allow for the footprint of two 660 mm diameter vessels side by side, and confirm doorway clearance during pre-install. In-service weight is approximately 690 kg total; confirm floor loading.
Is it noisier than the single Pure?
No — the Twin Pure runs the same single variable speed pump at the same 40 dB(A). The added capacity is in the storage vessels, which are silent.
Is a single-vessel version available?
Yes — the single-vessel ATX-450 Pure offers the same Flow-Thru hygiene specification with one 450L vessel at a lower price point. Choose the Twin Pure where peak flow, sustained capacity, or simultaneous-outlet demand justifies the additional vessel.
-
Data Sheet PDFDownload
-
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.
You may also need
The WaterBoost ATX-450 Pure is the hygiene-specification version of our highest-capacity ATX booster, connecting directly to the incoming cold water mains. It pairs a 450-litre…
The WaterBoost ATX-450 is the highest-capacity model in the ATX integrated accumulator booster range, connecting directly to the incoming cold water mains. It combines a…
The WaterBoost ATX-170 Pure is the hygiene-specification version of our 170-litre ATX booster, connecting directly to the incoming cold water mains. It pairs a 170-litre…
The WaterBoost ATX-300 is the second largest model in the ATX integrated accumulator booster range, connecting directly to the incoming cold water mains. It combines…
Related products
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-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-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 ×…
Frequently Asked Questions
Quick answers to common questions about the WaterBoost ATX-450 PURE Twin Whole House Mains Pressure Booster. 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.