Mark Schlotel, Marketing Manager at Cistermiser and Keraflo, talks to School Building about the importance of managing water safety in schools and explains how sometimes it’s the smallest things that can make the biggest difference.


Providing safe stored water in schools

As the saying goes, good things do come in small packages and it’s the products that we don’t necessarily see on a day to day basis that make the biggest difference. Float valves are a good example. A small component that most of us would have no need to consider and yet the implications to water safety and efficiency are significant.

Controlling water levels in cold water storage tanks is essential but becomes particularly important in schools where there is a large number of users and variable demand – for example during school holidays, there are significant periods of non-use or far reduced usage.

Conventional Vs delayed action 

Conventional equilibrium valves can potentially create problems when water is drawn from the tank. The float-operated valve opens slightly, and a dribble of water refills the tank. This doesn’t happen quickly enough for the water entering the tank to mix forcibly with the existing tank water, which can lead to stagnation. Add this to low or no-usage through the summer months and the temperature of the water in the storage tank can rise to above 22°C which places it in the risk zone for proliferation of bacteria, such as legionella.

Delayed-action valves provide an excellent alternative and only activate when the water falls to a pre-set level in the tank, opening fully to achieve a fast refill at a velocity that will mix the water in the tank and prevent stagnation. Keraflo have developed the leading range of delayed-action mechanical float valves on the market and these proven devices are ruggedly built to last, providing unbeatable value in terms of cost-in-use over considerable periods of time.

St Andrew’s School retires old Aylesbury float valve after 24 years

A primary school in Uxbridge has retired its Aylesbury cold water storage tank valve after 24 years of service, so its successor can now take the strain. The original Aylesbury K-Type delayed-action mechanical float valve had been in constant daily use since the 1990s, meeting all the water needs of the school’s staff and 200+ children.

Spare parts were no longer readily available to fit a valve of that age, so manufacturers Keraflo recommended that the best solution was to upgrade the system by fitting the modern version of the Aylesbury K-Type valve.


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The school’s water tank valve was originally installed when the London Borough of Hillingdon carried out a project to upgrade all water tanks across the Borough’s school premises in 1994. Many of those Hillingdon schools have long since been refurbished or replaced, but the valve at St Andrew’s Church of England Primary School has been “going strong” and working every day to ensure the water demands at the site are met.

The school’s Site Manager, Gerard McGuire, told Keraflo that he had experienced very little trouble with the valve at all.  He said “It’s been going for 24 years, which is not bad. You can’t argue with that as it’s been working constantly over that time.”

A small leak caused by wear and tear could have led to possible flooding in the offices and school rooms sited adjacent to the water tank, so the decision was taken to install a brand new Aylesbury K-Type valve. A local plumber installed the new replacement valve quickly and easily. This was the most efficient and practical way to solve the problem and ensure the school’s daily life was not disrupted.

Durability & longevity

Neil Weston, Keraflo’s Technical Sales Manager, remembers the original London Borough of Hillingdon’s upgrade and refurbishment project. It was one of his first work assignments on joining Keraflo. “Whilst not unusual, it is still a pleasant surprise to visit a site and see a float valve of this age in such an excellent general condition,” says Neil. “The only component that had worn at St Andrew’s School has long been replaced by one of a different material that will not wear in the same way. We can be confident that our latest Aylesbury valve models will continue to deliver durability and longevity. In this day and age of a ‘disposable society’ it’s still good to see a British manufacturer building products to last the life-cycle of a building.”

For more information on choosing the correct valve for your school building, contact Keraflo on 0118 921 9920 for specification advice or visit the website. 

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