www.heatingandventilating.net Accommodating old and new
The existing heating system is open vented. As is common with this type, oxygen ingress can occur, causing corrosion and the build-up of sludge. For this reason, and as it already suffered from poor circulation and was prone to blockages, a system chemical clean and flush was carried out. Due to its age, the concern was what problems would occur when the system was pressurised. For this reason, a plate heat exchanger, connecting (and hydraulically separating) secondary and primary circuit, was installed. This allows an adequate system flow through the boilers and protects them from magnetic sludge and debris present in the secondary circuit. New pipework has been used in the primary circuit which the Upton is connected to. The old system is fed from a tank located in the
roof from where it gets its static head pressure which was kept for the secondary circuit. As part of the boiler replacement design, numerous valves are installed at low and high points of the system. This allows to isolate sections and flush them again at a later point when the proposed plan is to replace the existing heat emitters. To create the pressurised primary circuit which the Upton boilers require, a Hamworthy Burstock expansion vessel and Chesil wall mounted single pump pressurisation unit were installed. A Hamworthy Clenston air and dirt separator to catch any further debris and Horton dosing pot to introduce chemicals such as corrosion inhibitor into the system have also been added to the secondary circuit. To accommodate the new boiler, the gas supply had to be upgraded, too. Additionally, a new flue was required to deal with the condensate and pressure in the new system which posed another challenge.
Refurbishment vs conservation
As a Grade II* listed building, Upton House is subject to rules ensuring that any works do not affect its appearance. This means the new flue had to meet strict guidelines and aesthetic requirements. It was designed and relocated from its original position and moved to the middle of an internal quad, so it could not be seen from outside the building. Mike comments: “While we do understand the
conservationists’ concerns of visual impact on the building, we have to make sure that health and safety isn’t compromised. We’re pleased to have found a solution. The design managed to let the flue terminate at a relatively low level. It was also painted, so it matches the colour of the building. It looks much better now – the old flue was rather unsightly and the new one is basically entirely hidden from visitors’ sight.” Any development of the building also requires a
refurbishment and demolition survey which is intrusive, as there is always a risk that a wall that is being drilled into can contain asbestos. Health and safety, costs and quality are of concern
for the council when choosing who they are working with and what products to use. Mike continues: “We have to not only watch the
money we spend but also make sure the contractors we choose carry out quality work, following all health and safety guidelines. It’s about quality, price and getting the right people.”
www.heatingandventilating.net
The old flue at Upton House
Listed buildings
Built-in boiler controls and further planned work
Upton House PHE and the Upton boiler
While the old heating system had a finite form of control, the new boiler modules are set up to run in sequence from the built-in boiler controls. Both running at minimum modulation allow for better system efficiency than only one operating at high capacity. The boiler is connected to combined room sensor controllers, also provided by Hamworthy, installed in the basement (storage of materials and consumables), on the ground floor (function rooms, often used for conferences and other events such as weddings) and first floor (office space for the co- ordination of council activities). These three different so-called ‘heat zones’ have been set up with different temperatures and start up times to accommodate individual area use.
The new flue at Upton House The new boiler controller
Everything is much more comfortable for staff and visitors
The old boilers at Upton House
Before, the building users had to turn the heating in the entire building on or off. With the new zone control, each floor can now be operated at different hours and reduce energy wastage thanks to dedicated room sensors and control valves. With the installation of an external air sensor, the heating flow temperature now also regulates depending on outside temperatures (weather compensation), reducing energy wastage. Generally, the new boiler modulates its output depending on the heat requirement. However, owing to the existing installation of temperature-sensitive fan convectors in the building which inadvertently shut off when flow temperatures are too low, the boiler’s ability to fully compensate is currently constrained. While the Upton operates at 85/65°C maximum flow and return temperature, the maximum secondary system flow and return temperature is then at 80/60°C for the heat transfer to take place on the plate heat exchanger. This is why a limited flow and return temperature weather compensation setting has been used. BCP Council is planning to remove the fan convector
heaters as part of its ongoing refurbishment to enhance the aesthetic aspect of Upton House, and to improve the weather compensation They are going to be replaced with period-style radiators made from steel for an authentic look.
Noticeable improvements and the Hamworthy experience
Mike commented: “We’re experiencing better circulation. The heating zones and control accuracy of the system is a vast improvement. Everything is much more comfortable for the staff and visitors. We’ve also improved the visual aspect by upgrading the flue.” About working with Hamworthy he concludes:
“I’ve known Hamworthy all my life, I really wouldn’t want to go anywhere else. Their support was exceptionally good. Trevor Struck, our local contact, is quick to respond and always happy to assist. As a council, we’re keen on building long-term relationships and working with Hamworthy has been what we’re looking for.“
June 2019 35
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