Boiler Repair, Service & Installation in Kennington (SE11)

The 2021 Census counted 10,197 households in SE11, and 73.7% of them live in purpose-built flats, more than four times the share across England (17.1%). 60.1% heat with mains gas alone, so a gas combi in a kitchen cupboard is the usual set-up. The Valuation Office puts 21.1% of the district’s properties at 2009 or later, and 17.6% between 1930 and 1939.

Small homes, big boilers.

Short cycling in a small flat

A combi is usually chosen for the hot water. Filling a shower or a bath as fast as the mains allows takes far more heat than warming a flat, so a boiler big enough for the taps can be several times bigger than the radiators need. Modern boilers turn themselves down to suit, but only so far: each has a lowest output it can hold, and on a mild day a flat in a block, with warm neighbours above, below and to the side, may need less than that. The boiler lights, heats the radiator water to its target in a minute or two, has nowhere to put the heat, shuts down, waits, and lights again. That on, off, on pattern is short cycling. You see it as a boiler that fires and stops many times an hour, radiators that go hot and cool in turns, and a room that never settles. Each start is wear on the ignition, the fan and the gas valve, and a boiler that never runs steadily wastes some of the gas it burns. The smaller and snugger the flat, the more often it happens.

Much of the fix is setting, not parts. Many boilers let the engineer cap the heating output well below the hot water output, so the heating suits the flat while the taps still get the full rate; some makers call this range rating. Many also have a setting for how long the boiler waits before it relights. Both sit in the boiler’s own menus, so the engineer sets them, and the yearly service is a good time to ask for them to be checked.

Valves and pipework matter too.

If every radiator has a thermostatic valve and they all close at once, the water has nowhere to go and the boiler cycles harder still. A radiator left without a thermostatic head, often the towel rail, or a bypass valve on the pipework, keeps a path open. Those are our work, and we check them before anyone touches the boiler’s settings.

When the boiler is due for replacement anyway, the answer is a model whose heating output turns down low enough for the flat, and we also arrange boiler installations in SE11 chosen that way.