38 HPM 1216

HPM-12-DEC-2016

38 T R A I N I N G & T E C H N I C A L As a continuation of a new initiative from Worcester, Bosch Group, aimed at helping installers to proactively tackle the most common reasons for call backs, Ewan Sutherland, engineering and services manager, explains the issues faced when replacing an existing regular boiler with a new one Over 300,000 gas fired regular boilers are installed across the UK every year, with the vast majority of these coming as part of a replacement. In these cases, it is important for installers to consider the differing requirements between the existing and the new boiler as, due to changes in efficiency requirements, modern boilers come with a range of necessary features that their predecessors often didn’t. At the end of a demand in new lightweight modern boilers, there is an amount of residual heat left within it. Most regular boilers on the market require a direct electrical connection to a circulating pump that will disperse this residual heat, helping to prevent any overheat issues and make use of the remaining heat efficiently. Installers will often find that older boilers do not have a pump over-run facility. This is because these older systems were significantly bigger with a higher thermal mass that could absorb this heat. Rather than putting the residual heat left in the system to use, it would just generally disperse over time through the flue or casing. However, with the regulations that are now in place and the desire for higher efficiency among smaller boilers, connection to a pump over-run facility is essential to keep the boiler working at its most efficient. What’s the problem? Although connecting a pump to a boiler may not sound difficult, if the boiler being replaced did not have a pump over-run requirement there will be no wire already in place to connect the two. This means that during installation, it will be necessary to run a wire from where the pump is currently cited down to the new boiler. Due to the most common location of the circulating pump – typically found in the loft – this isn’t always easy, especially in large houses which have more than two stories. In some cases, installers find they will need to remove floorboards and fitted carpets in order to get this wire back to the boiler, which can be a lot of disruption to homeowners. Some may even decide to go ahead and have the new boiler installed without linking the pump back to the boiler. This can result in problems in the long run, as heat building up in the boiler can lead to overheating and the system being locked out. The solution In situations where connecting the pump to the boiler with a physical wire proves challenging, there is an alternative solution which prevents the need to take up the flooring. So if you are installing a Worcester Greenstar RI boiler that requires connection to the circulating pump then it’s possible to install a radio frequency (RF) receiver and transmitter to facilitate the pump over-run. These are off-the-shelf components that can be purchased from most radio spares, and enable the pump and boiler to be connected through radio signals rather than a physical wire. First, the transmitter should be wired to the boiler, which registers its state, and a receiver is wired to the pump which is able to activate it. When in place, the connected transmitter registers when the A typical pump over-run boiler is requesting the pump to be energised and sends a RF signal in order to communicate with the receiver. This in turn registers that the pump needs to energise and activates it to disperse the residual heat left in the boiler heat exchanger, preventing the system from overheating and making it more efficient. The benefits This option presents both a time effective and cost-effective solution to a fairly common problem, with most standard RF devices costing between £40 and £50. Installing a transmitter and receiver means there is no physical wire connecting the two parts of the heating system and installers don’t have to worry about taking up flooring in order to connect the two. Additionally, since this method of installation gives the boiler a permanent live connection, it also ensures long-term durable operation that homeowners can be confident in. Pump over-run options www.hpmmag.com December 2016 enquiry number 133 “Over 300,000 gas fired regular boilers are installed across the UK every year, with the vast majority of these coming as part of a replacement”


HPM-12-DEC-2016
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