Name: WaterBoost 300 Litre Horizontal Accumulator Vessel AWBH-300LH
Brand: WaterBoost
SKU: AWBH-300LH
Price: 685.2 GBP
Availability: InStock

WaterBoost 300 Litre Horizontal Accumulator Vessel AWBH-300LH

WaterBoost 300 Litre Horizontal Accumulator Vessel AWBH-300LH - Image 2

WaterBoost 300 Litre Horizontal Accumulator Vessel AWBH-300LH - Image 3

WaterBoost 300 Litre Horizontal Accumulator Vessel AWBH-300LH - Image 4

WaterBoost 300 Litre Horizontal Accumulator Vessel AWBH-300LH - Image 5

WaterBoost 300 Litre Horizontal Accumulator Vessel AWBH-300LH - Image 6

In stock

Established 1975
Trusted by thousands of customers

The WaterBoost AWBH-300LH is a 300-litre WRAS-approved horizontal accumulator vessel for mains-connected water systems. The horizontal orientation makes it ideal where headroom is limited — fitting neatly in a loft, cupboard, or plant room on its side. Accumulators store mains water under pressure so you draw instantly at full mains pressure the moment you open a tap or shower, delivering noticeably stronger, more consistent flow even during peak demand periods.

The AWBH-300LH operates on a 60% usable volume ratio — delivering approximately 180 litres of high-pressure water before returning to normal mains flow. At a typical shower flow of 12 l/min, 180L supports two simultaneous showers for approximately 7.5 minutes before returning to normal mains flow. Diaphragm design, WRAS-approved construction, maintenance free. The AWBH-300LH is the largest in the horizontal range, suited to 3 bedroom+ homes with higher simultaneous demand.

Requires a minimum 2 bar static mains pressure to operate effectively. If your static pressure is below 2 bar, add the WaterBoost ACF1 accumulator booster pump to charge the vessel to the required working pressure.

300L

Vessel size

180L

Usable output

10bar

Max pressure

WRAS

Approved

WRAS approved
Horizontal — low headroom
Maintenance free
3 bedroom+ homes
ACF1 pump if <2 bar

Full Description

More about this product

Full Description

Product overview

The WaterBoost AWBH-300LH is a 300-litre WRAS-approved horizontal accumulator vessel for mains-connected cold water systems. The horizontal orientation means it installs on its side — ideal for lofts, low-ceiling cupboards, and plant rooms where a vertical vessel would not fit. It stores mains water under pressure so that when you open a tap or shower, water discharges immediately at full mains pressure rather than waiting for the street main to respond.

The vessel operates on a 60% usable volume ratio, delivering 180 litres of high-pressure water per charge before recharging automatically from the mains. Diaphragm design, WRAS-approved construction, maintenance free and completely silent — no pump, no electronics, no servicing required once installed.

Requires a minimum 2 bar static mains pressure. If your pressure is below 2 bar, add the WaterBoost ACF1 boost pump to charge the vessel to the required working pressure.

300^L

Vessel size

180^L

Usable output

10^bar

Max pressure

Horiz.

Low headroom

WRAS approved · Maintenance free · Silent operation

Why choose horizontal?

Loft installation

The horizontal design fits in low-headroom loft spaces where a vertical vessel of equivalent capacity would not stand upright.

Cupboard & plant room

Fits neatly inside a standard airing cupboard or plant room on its side — where vertical height is limited but floor footprint is available.

Identical performance

The horizontal orientation has no effect on performance — the vessel delivers the same pressure and flow as an equivalent vertical model.

How it works

1 — Vessel fills under mains pressure

The accumulator connects to the mains and fills automatically. The internal diaphragm compresses as water enters, storing energy as pressure.

2 — Water discharges at full pressure

When a tap or shower opens, pressurised water discharges immediately from the vessel — delivering strong, consistent flow from the first moment.

3 — Vessel refills from mains

Once demand ceases, the mains refills the vessel automatically. No pumps, no controls, no maintenance — entirely self-managing.

60% usable volume rule. WaterBoost accumulators operate on a 60% usable ratio — multiply vessel size by 0.6 to find usable litres per charge. The AWBH-300LH delivers 180 litres per charge. At a typical shower flow of 12 l/min, 180L supports two simultaneous showers for approximately 7.5 minutes before returning to normal mains flow.

Key features

WRAS approved

Fully compliant for use with potable (drinking) water in the UK. WRAS-approved construction throughout.

Maintenance free

No pump, no electronics, no moving parts outside the diaphragm. Once installed, the vessel operates without servicing.

Diaphragm design

Internal diaphragm separates the pressurised air charge from the water supply, ensuring clean potable water delivery at all times.

10 bar max working pressure

Rated to 10 bar maximum — well above any domestic mains supply, with a significant safety margin built in.

Completely silent

No pump means no noise. Suitable for any room — including lofts directly above bedrooms and living areas.

ACF1 compatible

Fully compatible with the WaterBoost ACF1 boost pump for installations where mains static pressure is below 2 bar.

Sizing guide

Recommended vessel sizes for the AWBH horizontal range, based on property type.

Property	Recommended vessel	Usable output
1–2 bedroom home	60L, 100L or 150L	36L, 60L or 90L
2–3 bedroom home	150L, 200L or 250L	90L, 120L or 150L
3+ bedroom home this product	250L or 300L	150L or 180L
3+ bedroom home	250L or 300L	150L or 180L

To calculate your own usage: Multiply vessel size × 0.6 to get usable litres. Divide by your total flow demand to find duration. For example: AWBH-300LH delivers 180L usable. With two showers at 12 l/min each, that is approximately 7.5 minutes of simultaneous boosted flow.

Technical specifications

Brand / Model	WaterBoost — AWBH-300LH
Vessel capacity	300 litres
Usable output (60% rule)	180 litres per charge
Orientation	Horizontal
Max working pressure	10 bar
Internal design	Diaphragm
WRAS approved	Yes — potable water
Maintenance	Maintenance free
Min mains pressure required	2 bar static (resting)

Frequently asked questions

How much does it cost?

£571.00 + VAT (£685.20 inc VAT). Please contact us for delivery timescales on this product.

Does the horizontal orientation affect performance?

No. Accumulator vessels perform identically whether oriented vertically or horizontally. The horizontal AWBH range delivers the same pressure, flow, and usable volume as an equivalent vertical AWB vessel of the same capacity.

What mains pressure do I need?

A minimum 2 bar static (resting) mains pressure is required. If your static pressure is below 2 bar, add the WaterBoost ACF1 accumulator booster pump to charge the vessel to a higher working pressure.

Should I choose this size or a larger vessel?

The AWBH-300LH is the largest in the horizontal range, suited to 3 bedroom+ homes with higher simultaneous demand. For higher demand, consider the AWB vertical range (up to 450L). If headroom allows a vertical installation, the WaterBoost AWB vertical range offers sizes up to 450L.

Does the accumulator need any ongoing maintenance?

No. WaterBoost accumulators are maintenance free. The pre-charge pressure can be verified periodically using a standard tyre pressure gauge on the Schrader valve and topped up if necessary — no specialist knowledge required.

Downloads

data sheet PDF
Download
Manual PDF
Download

Delivery Information

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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