Lullington Boiler Installation

What a proper heating quote should include

A quote worth relying on states the specific boiler or equipment model, the labour and materials it covers, whether a system flush and magnetic filter are included, what happens to old equipment removal and disposal, and what's excluded — an unexpected gas pipe upsizing or asbestos-containing material discovered during removal, for example, which can't always be known before work starts. It should also state who's completing the Gas Safe or OFTEC notification and Benchmark commissioning record, since that's the paperwork that protects both the manufacturer's guarantee and the property's compliance history when it's sold. A vague one-line quote makes comparing genuinely different offers difficult, because two prices that look similar can cover very different scopes of actual work.

• Specific make and model, not just "combi boiler"
• Flush and magnetic filter stated as included or excluded
• Old equipment removal and disposal covered
• Notification and Benchmark record responsibility stated

What different boiler noises usually mean

A kettling or rumbling sound from a boiler is most often scale or sludge build-up on the heat exchanger causing localised boiling as water is trapped and overheated in restricted channels — the heating equivalent of a kettle furring up. A banging or knocking sound in pipework, sometimes called water hammer, is usually caused by a valve closing too quickly or trapped air rather than the boiler itself. A whining or humming sound tends to point to the circulating pump, either from wear or from air in the system reducing lubrication at the bearing. Diagnosing correctly from the noise alone isn't reliable enough to act on without checking system pressure, inhibitor condition and the pump directly, but the noise itself is a useful first indicator of which of those to check first.

Gas pipe sizing and working pressure drop

Swapping to a higher-output combi or adding an extra gas appliance means the existing gas pipe has to be checked against the new total demand, not just the boiler's own rating plate. Gas Safe installation procedures require a working pressure test at the appliance under full load, and IGE/UP/2 tables set the maximum permitted pressure drop over the pipe run length and diameter. A run that was adequate for a 24kW back boiler can be undersized once a modern combi with a larger instantaneous hot water draw is fitted on the same 15mm supply. Where the test shows an unacceptable drop, the fix is upsizing to 22mm or shortening the run — not turning the boiler down, which just masks the underlying restriction.

Pumped-oil versus gravity feed: does it matter?

Older oil systems sometimes still rely on gravity feed, where the tank sits higher than the burner and oil flows down to it under its own weight; a pumped system uses the burner's internal pump to draw oil up from a tank at any level, including below the boiler. Gravity feed limits where a tank can be sited and is more prone to airlocks if the line runs dry, while a pumped system is more flexible on tank position but needs the pipe run and lift height kept within the burner pump's rated capacity — usually no more than a few metres of lift and a set maximum run length. When we replace an oil boiler we check which type the existing tank and pipework support before assuming a straight swap, because a tank sited for gravity feed may need repositioning or a different pump to suit a modern burner.

Radiator sizing after lowering the flow temperature

Running a boiler at a lower flow temperature — typically 55°C or below rather than the old default of 70-80°C — improves condensing efficiency measurably, but it also reduces the heat output of every radiator in the house, because a radiator's output falls roughly with the square of the temperature difference to the room. Radiators sized correctly for a 75°C flow can end up unable to heat the room properly at 55°C unless they're upsized or supplemented. We check each radiator against the lower design flow temperature before recommending it, and where a room falls short we look at whether a larger single panel, a double panel, or an additional radiator on that circuit closes the gap, rather than pushing the flow temperature back up and giving away the efficiency gain.

What a flue gas combustion analysis actually tells us

A combustion analyser measures the flue gases leaving a boiler — oxygen, carbon dioxide, and carbon monoxide content, along with flue temperature — and from those figures calculates the boiler's actual combustion efficiency and confirms it's burning cleanly rather than producing dangerous carbon monoxide. It's a required part of every gas and oil service and commissioning visit, not an optional extra, because visual inspection alone can't detect incomplete combustion. Readings outside the manufacturer's specified range point to a specific fault — a partially blocked burner, incorrect gas or oil pressure, or a fouled heat exchanger — rather than a general sense that something's wrong. We record the readings on every service so any drift between visits is visible, not just the pass/fail result on the day.

Nozzle replacement and baffle cleaning on oil burners

An oil burner's nozzle atomises fuel into a fine spray for combustion, and it wears from constant fuel flow at pressure, gradually changing the spray pattern away from the burner manufacturer's specification even before it visibly fails. A worn nozzle burns less cleanly, producing more soot that coats the heat exchanger's baffles, and a sooted heat exchanger loses efficiency in the same way scale does on a gas boiler's plates. Standard practice on an annual oil service is to replace the nozzle as a matter of course, rather than wait for a fault, and to remove and clean the baffles so the heat exchanger surfaces are exposed to combustion heat properly again. Skipping nozzle replacement to save a service visit's minor parts cost is a false economy against the fuel wasted by a poorly atomising burner.

Commissioning checklist and the Benchmark record

Every new boiler installation comes with a Benchmark commissioning checklist that has to be completed and signed at the point of installation — recording gas or oil pressure readings, flue gas analysis results, system flush confirmation and control settings. It's not paperwork for its own sake: manufacturers require a fully completed Benchmark record as a condition of the boiler's guarantee, and an incomplete or missing record is one of the most common reasons a warranty claim gets refused later. We complete and hand over the Benchmark log, along with the Gas Safe or OFTEC notification, on the day of installation rather than promising to send it on, specifically so the paperwork exists from day one if it's ever needed.