Commercial Plant Room Upgrade — Belgravia

There's a particular anxiety that comes with managing a residential block in Belgravia. The residents expect a great deal — and rightly so. When the heating infrastructure underpinning eight high-value apartments is kept together with increasingly scarce spare parts and institutional optimism, that anxiety becomes acute.

The freeholder of this eight-apartment block had been managing exactly that situation for two years. The plant room in the basement contained two Potterton commercial boilers dating from the early 2000s. One had already been repaired three times in 18 months; the other had a pump that was being held in reserve — the last one the engineer could source before that model was discontinued. Both units were failing intermittently, and neither had parts availability that would last another winter.

Beyond the equipment itself, the plant room had accumulated 20 years of piecemeal interventions: redundant pipework from a previous DHW cylinder that had been decommissioned years ago, a pressurisation unit that needed manual attention quarterly to stay within operating range, and a flue arrangement that had grown organically rather than been designed. It was functional — just barely — but it was not the plant room of a building that should be able to offer its residents confidence in their heating infrastructure.

The brief was unambiguous: design and install a plant room that would provide reliable, efficient, properly documented heating for the next 15 to 20 years — and do it without leaving eight occupied apartments without heat.

RARE's specification centred on twin Viessmann Vitodens 200W 49kW boilers in a cascade configuration. This decision was driven by two principles that are often in tension: efficiency and resilience. A cascade of two matched boilers can modulate output far more precisely than a single large unit — firing one boiler at low load rather than cycling a single oversized boiler — which significantly improves efficiency and reduces wear. It also provides built-in redundancy: if one unit requires servicing, the other continues to provide partial heating to all apartments.

The three-day programme was planned with military precision around one non-negotiable constraint: the residents. Temporary electric space heaters were arranged for the common areas, and the installation was sequenced so that each boiler was connected and operational before the other was taken offline. At no point over the three days were all eight apartments without any form of heating.

Beyond the boilers themselves, the plant room was fundamentally reorganised: all redundant pipework was removed and the primary circuit was reconfigured for optimal hydraulic performance; a new Reflex pressurisation unit replaced the failing existing unit; and the flue arrangement was completely redesigned and updated to current Building Regulations, properly documented and photographed throughout.

On completion, RARE issued Gas Safe certificates for both new boilers, CP12 certificates for all gas appliances in the building, and a comprehensive plant room log book covering all equipment, service intervals, commissioning data and emergency procedures — everything the managing agent needed to take the plant room from a liability to an asset.