Employing non-specialist contractors to maintain heat networks is problematic, argues Steve Morris of Insite Energy.
Unless correctly monitored and maintained, heat networks become less efficient over time. A host of serious problems can result, including higher energy costs. This can cause hardship for residents and leave some unable to pay, increasing financial risk for housing providers and putting vulnerable households in danger. Inefficiency also means higher emissions and potential safety issues. Plus, poorly maintained equipment fails more quickly, driving up repair costs, shortening replacement cycles and leaving residents in the cold.
Heat networks are high-value assets and must be properly looked after to ensure they live up to the substantial benefits they promise.
Skills shortage
Finding a maintenance contractor with the right expertise is hard. Even the most qualified and highly experienced engineers may not know how to keep a heat network working optimally. We’ve been working with heat networks since 2009 and hiring people with the right experience is a perennial issue. Although the technology is growing rapidly in popularity, it’s still new and there’s a skills shortage. Our solution is to train maintenance engineers in-house.
Heat network maintenance differs significantly from ordinary boiler maintenance. A heat network is not an enclosed system. All parts within it are connected to, and interact with, the whole. Engineers must be able to think in terms of the entire system – not just individual sections.
Furthermore, while a heat network plant room is similar to that of any large commercial or public building, the ways in which it connects with the individual dwellings on the network are very specific. This can cause numerous serious errors.
Common problems
Many of the mistakes we encounter relate to the return temperature in combined heat and power (CHP) systems. This must be within a certain range for the heat network to function properly. If it’s too high, the system shuts down. A very common slip up inexperienced engineers make is turning all settings up to maximum when a resident complains of having no heating or hot water. The system then tries to pre-heat to that higher temperature too often, working harder to try and meet demand. This causes inefficiencies because the return temperature is far higher than necessary.
Other problems occur because engineers don’t understand how heating interface units (HIUs) and metering and billing systems work and interact with the rest of the network. Each solution has its own idiosyncrasies and, while HIUs appear similar to traditional boilers, they can’t be treated identically. When servicing an HIU, engineers will often just check for leaks and dirt. But that’s a spot check, not a service. In fact, they should ensure the unit is operating within the recommended tolerances to achieve the CIBSE CP1 industry standard. That means checking things like whether a certain temperature is achieved at the furthest source within a certain time period.
Monitoring energy usage is another area where issues often arise. If a system fault causes a prepayment valve to shut, as it would if a resident doesn’t pay their bill, an inexperienced engineer is likely to simply bypass it instead of investigating the cause. That means the heating is on all the time, racking up big bills until the fault is noticed and an expert called in.
Despite all the potential pitfalls, the ever-increasing pressure to keep costs down for the sake of residents can make it tempting for housing providers (many of whom are new to heat networks themselves) to choose the cheapest maintenance quote. However, the energy crisis is also drawing greater levels of scrutiny to purchasing decisions and there’s often a bigger price to pay when upfront costs take precedence over long-term value.
Getting it right
Good O&M contracts are very specific about how equipment will be maintained, e.g. stripping down and checking bearings instead of simply looking for leaks. Precise terminology ensures you know exactly what you’re paying for. Draw up a tick box list of activities so everyone’s clear about the terms. A good way of doing this is to stipulate that equipment should be maintained to industry standards like CIBSE CP1 for HIUs or SFG 21 for plant.
Wherever possible, seek out maintenance teams with proven expertise in heat networks. To do so, find out what experience they have of commissioning and servicing HIUs, ask for references of current customers – and follow them up, and check potential suppliers can explain in detail how your system actually works and how they intend to maximise efficiency and reduce heat loss. If they can’t explain it, they can’t maintain it!
Consider introducing data monitoring at property level to highlight and rapidly fix inefficiencies. Data analytics applications are becoming increasingly affordable and offer incredibly quick payback. In a recent example at a client site, data analysis enabled us to pinpoint a minute error – a transport clip left on a HIU valve – that was costing around £1,000 per year in wasted energy. This is a perfect illustration of the concrete benefits that the right expertise can supply. O&M contractors proposing innovative data tools are more likely to have that kind of knowledge you need.
As more heat networks are built and commissioned, and heating contractors upskill, many of the new technology teething problems housing managers are now experiencing will resolve themselves. Until then, we’re helping as many clients as possible get the assistance they need.