Recalculating after an extension
A single-storey rear extension with large glazing can add 1.5–3kW of heat loss on its own, and it often sits at the end of the flow circuit where temperatures are already lowest. Correct practice is to recalculate room-by-room loss, check the existing radiators are still adequately sized for a lower flow temperature, and upsize where they are not. This is why an extended Walsgrave semi sometimes needs two new radiators rather than a larger boiler.
Vented to sealed system conversion
Converting a traditional gravity-fed system means removing the feed-and-expansion tank and cold-water storage tank, fitting an expansion vessel and pressure relief, verifying every radiator and joint can hold sealed-system pressure, and reworking the hot-water arrangement — either to a combi or to an unvented cylinder. Old joints that leaked slowly at gravity pressure will announce themselves at 1.5 bar, so we pressure-test before making good.
Unvented cylinders in larger CV2 2 homes
For a four-bedroom Woodway Park house with two bathrooms, a system boiler around 18–24kW with a 210–250 litre unvented cylinder gives mains-pressure hot water everywhere at once. It requires a G3-qualified installer, a compliant tundish and discharge route, and an annual check on the safety devices. Recovery time matters more than raw storage for a family — a well-matched boiler reheats the cylinder while the household is getting ready.
Flow temperature, condensing and running cost
A condensing boiler only condenses when the return temperature is below roughly 55°C. Many are commissioned at 75–80°C flow, which effectively disables that efficiency. Where radiators allow, we set flow temperature lower and use weather or load compensation, which typically cuts gas use by several percent for no extra hardware cost in the right setup.
Loft tank removal and freeze prevention
Post-war Walsgrave lofts often have tanks perched above the insulation. Removing them during a combi conversion eliminates the annual freeze risk, the overflow pipe and the stored-water contamination question. Where a cylinder is retained, we insulate the pipework and check the tank lid and jacket instead.
What you receive on completion
Completed benchmark checklist, Gas Safe building-regulations certificate, manufacturer warranty registration, commissioning readings including gas rate and combustion analysis, and an itemised invoice matching the quote you approved.
