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Aylesbury KB Type Float Valve

delayed action float valve suitable for tanks with or without raised valve chambers

Price(s) From
£ 921.60
Price (incl. VAT)

Aylesbury KB Type Float Valve

delayed action float valve suitable for tanks with or without raised valve chambers

Price(s) From
£ 921.60
Price (incl. VAT)

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Product Information

Aylesbury™ KB Type fully variable float valves are specified for commercial water systems and are designed to provide an accurate and efficient method of controlling the level of stored cold water in tanks with or without raised float valve chambers.

Precision-engineered and built to last, all Keraflo Aylesbury™ patented delayed action float valves are manufactured under Quality Management Systems certified to ISO.9001:2015 and designed to operate for long periods of time without maintenance.

The valves are easy to install with an ‘up and over’ discharge arrangement which assists in facilitating Type AA, AB, AF, or AG air gap requirements under the Water Regulations.

The Aylesbury range is ideal for pumped systems because the open to closed ‘on/off’ valve operation avoids pump hunting and water hammer. The selected water level is unaffected by pressure fluctuation and the patented ceramic disc sealing mechanism means that there is no seat or washer to wear.

The positive action and full-bore flow delivered by the KB Type valve provide a range of benefits including good water turnover, fast refill, the eradication of water hammer and reduced noise, a virtually unlimited range of opening and closing levels (ideal for larger tanks) and easy adjustment of variables (capacity can easily be matched to demand).

The KB Type is ideal for fitting into a tank without a lid or raised valve chamber and where the vertical drop from the valve to the water level may be considerable, so this unique valve is ideal for use with pumped systems, water treatment plants and many other applications including: Industrial tanks, Pumped systems, Underground tanks, Rain (grey) water tanks and reservoirs, Industrial feed and expansion tanks and Process tanks.

The flexibility of KB Type valves can assist with improving water quality where buildings are partially commissioned or occupancy varies at different times of the year.

Pumped Systems – The adjustable and potentially large difference between opening and closing levels can allow a large volume of water to be admitted to the tank each filling cycle. Pumps and pump sets are often controlled to run for a minimum of 3 minutes. If the water demand is satisfied before this time and an auxiliary hydraulic accumulator is not fitted, the pumps will run against a closed valve head at zero efficiency.

The fill volume can be set to equal or exceed this volume to ensure the pump(s) run for at least 3 minutes. Where a pump set is used solely for transferring water from a break tank to an elevated storage tank, the KB valve can dispense with the need for an auxiliary hydraulic accumulator.

Pump efficiency and initial sizing can be further enhanced using a float valve with little internal resistance. Consequently the High Flow version is often better suited to these applications than the Standard Flow version which is ideal for mains water pressure applications.

Aylesbury KB Type fully variable delayed action float valve, suitable for tanks with or without raised valve chambers
Opening and closing operating differential
Fully variable, up to 1,820mm (and longer on request)
Water pressure range
Suitable for 0-10 bar
Float specification
Puncture-proof float, made from polyethylene closed cell foam which is CFC-free, air retardant and both chemically and biologically inert
Back-siphonage protection
Up and over discharge to BS1212 Part 2, which helps to facilitate air gap compliance
Product Features
Virtually indestructible, the heart of the valve incorporates pressure compensated rotating ceramic discs which are aligned in the open position
Reduced stress on the tank wall fixing point, due to the Aylesbury valve's radical design
Extended durability, with a non-wearing ceramic disc seal in a DZR brass housing
Maintenance free, designed to operate for long periods without maintenance
Improved water turnover, ideal for pumped systems, plus energy savings with positive pump control, maximised tank capacity, full flow during fill and reduced risk of Legionella
No valve bounce, dribble or incidence of water hammer
Ensures compliance with the Water Regulations

When water is taken from the tank and the water level falls (when a tap is opened for example), the Aylesbury KB Type float valve does not immediately open (at a dribble) as would happen with a BS1212 equilibrium valve. There is, instead, a delay; the valve does not open until the water level has fallen to the user-selected level.

When this opening water level is reached the KB Type valve moves from a ‘fully closed’ position into a ‘fully open’ position, allowing water to flow into the tank at a maximum flow rate. When the water level has returned to its original full level, the valve immediately closes from the ‘fully open’ position, preventing any of the ’dribbling’ associated with equilibrium valves.

Here is a selection of documents, designed to ease specification and installation:


Keraflo Product Range Guide

Download PDF
Product Leaflet

Aylesbury Delayed Action Float-Activated Valves

Download PDF
Installation Guide

Aylesbury KB Valve (20-50 DN)

Download PDF
Installation Guide

Aylesbury KB Valve (50-80 DN)

Download PDF
Quick Reference Guide

Keraflo Spares Kit

Download PDF
Specification Wordings

Cistermiser and Keraflo Product Ranges

Download PDF
Specification Catalogue


Download PDF
How the KB valve works

Aylesbury KB Valve

Benefits of using Aylesbury Valves

Keraflo Aylesbury Valves

BIM objects are available for download from the NBS National BIM Library, in both Revit and IFC formats.

Click here to view Keraflo products on the National BIM Library

Warranty Cover

Parts only warranty (no labour) for equipment purchased in the United Kingdom, Ireland, Isle of Man and the Channel Islands. Components of the unit which are proven to be faulty or defective in manufacture will be exchanged or repaired.

Warranty Period

1 Year from Date of Manufacture

Extended Warranty Period (available on Registration)

5 Years from Date of Installation

Extended Warranty Terms

To register and qualify for Extended Warranty cover, a photograph of the Keraflo Installation Label (included with the product and affixed to the Cold Water Storage Tank) with all installation and commissioning checklist activities completed should be sent via email to

The Keraflo Installation Label affixed to the Cold Water Storage Tank should be signed and dated with the installer’s name and the following details also provided to enable warranty registration: Keraflo product serial number, installation date and tank installation address/location.

Extended Warranty can also be registered online (via the Warranty section of this website).

What Our Customers Say...

We have been dealing with Keraflo since 2006 and have found both their products and customer service second to none.

Stuart Clark, Quality Manager, Nicholson Plastics Ltd

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Having dealt with Keraflo for over 16 years, we (Fraser & Ellis) are proud to be associated with and to offer a guaranteed quality product.

Paul Fraser, Managing Director, Fraser & Ellis Ltd

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The Keraflo valve has been and is a ground-breaking high quality product which never fails to deliver.

Norman Ross, Sales Director, Balmoral Tanks Ltd

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Catalogue Download
View our product range by downloading our Specification Catalogue!
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Product Warranty
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