WaterBoost ATX Whole-House Mains Pressure Booster
WaterBoost ATX-300 Whole House Mains Pressure Booster
- Established 1975
- Trusted by thousands of customers
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 a 300-litre sealed accumulator vessel with a variable speed pump in a single compact unit — 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 system delivers a peak burst flow of up to 45 l/min and up to 27 l/min at 3.2 bar for up to 11 minutes — before settling to a continuous boosted flow of 12 l/min at 3 bar until the vessel recharges. The 300-litre vessel provides 180 litres of useable working capacity. Variable speed inverter technology means the pump only generates the pressure your mains can’t already deliver, keeping running costs to a genuine minimum. Operation is measured at a quiet 40 dB(A). WiFi via the DConnect app enables remote monitoring and control. A mains bypass fits in seconds using 2 clips if the unit ever requires attention.
WRAS approved product. Fully sealed system — zero air contact with stored water, no hygiene management required. Completely maintenance free. Suited to 2-4 bed homes upwards, combi-boiler properties and unvented cylinder systems. 5-year tank warranty, 3-year pump warranty. Step up to the ATX-450; step down to the ATX-250 for smaller properties.
WRAS approved
Zero maintenance
Sealed — no air contact
Variable speed
300L · 180L useable
No overflow
Dry run protection
Bypass fits with 2 clips
More about this product
What is the ATX-300?
The WaterBoost ATX-300 is the second largest model in the ATX integrated accumulator booster range. It connects directly to your incoming cold water mains supply, combining a 300-litre sealed accumulator vessel with a variable speed pump in a single compact unit — automatically boosting both pressure and flow throughout the property the moment a tap or shower is opened. No break tank, no overflow arrangement, and just two water connections required.
The 300-litre vessel provides 180 litres of useable working capacity, enabling the ATX-300 to sustain a boosted flow of 27 l/min at 3.2 bar for up to 11 minutes — sufficient for two or more showers running simultaneously — before the vessel recharges automatically. Peak burst flow at the moment of demand is up to 45 l/min. Once the stored volume is exhausted, the system continues to deliver a boosted 12 l/min at 3 bar until demand ceases and the vessel refills.
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.
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 ATX-300 reflect exactly what is needed — nothing more.
Sealed system — zero air contact with your water
The ATX operates as a fully closed pressurised circuit from mains inlet to outlet. The accumulator vessel is sealed and pressurised — there is no open water surface, no air gap, and no point at which atmospheric air contacts the stored water. This is a fundamentally different design to an open storage tank system, with important advantages for water quality and safety.
The pump body is constructed from WRAS-approved materials throughout, confirming suitability for contact with potable water. The complete system carries WRAS approval.
✗ Open water surface — air, dust and debris can enter
✗ Requires periodic tank cleaning and inspection
✗ Overflow pipe required — ongoing hygiene risk point
✗ Water sits static — Legionella risk management may apply
✓ Fully sealed vessel — zero air contact with water
✓ No open surface, no dust or debris ingress
✓ No overflow pipe required
✓ WRAS approved product
WRAS approved product. Confirms the system meets UK Water Supply (Water Fittings) Regulations, is safe for use with potable water, and will not cause contamination of the mains supply.
Zero maintenance — fit it and forget it
The ATX 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 design removes the hygiene maintenance obligations of open storage, and the built-in anti-seize exercise function and dry run protection mean the system manages its own long-term health automatically.
What happens after installation
| Day 1 — Installation | Two water connections. Unit installed and commissioned. That’s it. |
| Year 1 — Nothing | No service visit. No filter change. No tank clean. 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. 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
The ATX-300 stores a ready supply of pressurised water in its 300-litre accumulator vessel. 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.
Phase 1 — Stored volume
Instant high-flow boost
27 l/min
at 3.2 bar — for up to 11 minutes
Delivered directly from the pre-charged accumulator. Sufficient for two or more showers running simultaneously.
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. Vessel recharges automatically when demand stops.
How it compares — WaterBoost ATX-300 vs Stuart Turner Stormboost 300
Both systems target the same market — 300-litre direct mains boosters for 2-bed homes upwards.
| Feature | WaterBoost ATX-300 | Stuart Turner Stormboost 300 |
|---|---|---|
| Pump type | Variable speed inverter ✔ | Fixed speed induction motor |
| Energy efficiency | Only boosts the shortfall ✔ | Fixed output regardless of mains |
| Sealed system | Fully sealed — zero air contact | Fully sealed — zero air contact |
| Noise | 40 dB(A) rated ✔ | Quiet — no dB rating stated |
| WiFi / App control | Yes — DConnect app + HMI ✔ | No |
| Overflow required | No ✔ | No |
| Maintenance bypass | 2-clip fit — 30 seconds ✔ | Integral bypass |
| Maintenance required | Zero — maintenance free ✔ | Periodic maintenance advised |
| Warranty | 5yr tank · 3yr pump ✔ | 3 years total |
Technical specifications
| Brand / Model | WaterBoost — ATX-300 |
| System type | Integrated accumulator booster — direct mains |
| Water connections | 2 — inlet & outlet |
| Accumulator capacity | 300 litres total · 180 litres useable working capacity |
| Peak burst flow | Up to 45 l/min |
| Sustained boosted flow | 27 l/min at 3.2 bar for up to 11 minutes |
| Continuous flow (post-discharge) | 12 l/min at 3 bar |
| Max pressure | 3.2 bar |
| Pump type | Variable speed inverter |
| Noise level | 40 dB(A) |
| WiFi / connectivity | Yes — DConnect app + on-unit HMI display |
| Sealed system | Yes — no overflow required |
| Air contact with water | None — fully sealed pressurised vessel |
| WRAS approved | Yes — complete system |
| Dry run protection | Yes — built in |
| Anti-seize exercise function | Yes — automatic |
| Maintenance bypass | Fitted in under 30 seconds using 2 clips |
| Maintenance required | None — completely maintenance free |
| Suited to | 2-4 bed homes upwards · combi-boiler properties · unvented cylinder systems |
| Warranty | 5-year tank · 3-year pump |
Flow rates are dependent on incoming mains supply. Continuous flow of 12 l/min applies after stored volume is exhausted.
Frequently asked questions
What is the difference between the ATX-300 and ATX-250?
The ATX-300 has a 300-litre vessel (180 L useable) compared to the ATX-250’s 250 litres, and delivers a higher sustained flow of 27 l/min versus 24.5 l/min. All other specifications — pump type, peak pressure, noise, WiFi and warranty — are identical across the ATX range.
Why is the ATX more energy efficient than a storage tank booster?
A storage tank booster always runs at full output regardless of mains conditions. The ATX’s variable speed pump measures incoming pressure and produces only the shortfall — if your mains provides 2 bar, the pump adds 1 bar. Over a year this makes a meaningful difference to running costs, particularly where mains pressure varies by time of day or season.
Why is a sealed system better for water hygiene?
An open break tank has an exposed water surface where airborne dust, debris and microorganisms can enter, and requires regular cleaning and inspection. The ATX has no open surface — the accumulator vessel is sealed and pressurised, operating as a closed circuit throughout with no point at which air contacts the stored water. WRAS-approved materials confirm suitability for potable water contact with no hygiene management requirements.
What maintenance does the ATX need?
None. There are no service intervals, no consumable parts, no filter changes and no annual engineer visits required. The anti-seize exercise function runs the pump automatically during inactivity to prevent impeller seizure. Dry run protection safeguards the pump if the mains supply is interrupted. The DConnect app allows remote monitoring. The system looks after itself.
What happens if the pump needs replacing?
The unique 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 mains bypass keeps your property on water throughout.
Is the ATX suitable for a combi-boiler or unvented cylinder property?
Yes. The ATX is designed for direct mains connection and is well suited to both combi-boiler homes and properties with unvented hot water cylinders. Installation should comply with Water Regulations and be carried out by a qualified plumber.
What happens after the 11 minutes of boosted flow?
Once the stored volume is used, the system continues to supply water at a boosted 12 l/min at 3 bar directly from the mains — there is no sudden drop to unboosted pressure. When demand stops, the accumulator recharges automatically. Actual flow rates depend on the incoming mains supply available.
-
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-200 is the second smallest model in the ATX integrated accumulator booster range, connecting directly to the incoming cold water mains. It combines…
The WaterBoost ATX-250 is the mid-range model in the ATX integrated accumulator booster range, connecting directly to the incoming cold water mains. It combines a…
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 AWB-300LV is a 300-litre WRAS-approved vertical accumulator vessel for mains-connected water systems. Accumulators store mains water under pressure — so when you open…
Related products
The WaterBoost WB-INT Slimline 300 is a complete, pre-built variable-speed water boosting system designed to solve low water pressure and flow in 3–5 bedroom homes.…
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-Coffin 320 Mini3 is a compact, variable-speed water boosting system engineered to overcome low water pressure or inadequate flow in domestic and light…