Solid fuel boiler install with buffer tank and safety group

I install solid fuel boilers the way they are meant to work: with a buffer tank, a proper anti-condensation loop and a safety group that is never optional. Work starts before a single pipe is cut. I walk the house, measure the heated area, look at the walls, the glazing and the insulation of the roof, and calculate the real heat loss. A wood or coal boiler cannot be throttled like a gas one — once the fire is lit it will give out what it gives out, so an oversized unit does not make the house warmer, it makes it swing between overheating and smouldering. Smouldering is the worst mode a solid fuel boiler has: it tars the heat exchanger, kills the draught and produces carbon monoxide, a gas with no smell and no colour that has killed people in their sleep. Correct sizing, a working safety group and a chimney with correct draught are what stand between the house and that risk, and I do not cut corners on any of the three.

The buffer tank is the heart of the scheme. The boiler burns a full load at its nominal output, in its clean and efficient mode, and the heat goes into the water store instead of being dumped into overheated rooms. After that the house is heated from the tank for hours, the radiators stay even, you load the firebox two or three times a day instead of feeding it constantly, and the emergency discharge of a boil-over stops happening at all. Between boiler and tank I fit a loading loop with a three-way thermostatic valve, so the water returning to the boiler is never colder than the dew point of the flue gases. Without that valve cold return water makes moisture and acid condense on the cast iron or steel, the exchanger clogs with sticky tar and rusts through in a couple of seasons.

The safety group goes on the boiler flow with no shut-off valve between it and the boiler: a relief valve, an automatic air vent and a pressure gauge on one manifold, plus a discharge pipe routed where scalding water cannot reach anyone. I size and mount the expansion vessel, pressurise it to the static head of the system, install the circulation pumps with isolating valves and a dirt separator, connect the heating circuits, fit the thermostats and the boiler control, and check the chimney: cross-section, height, insulation, a tee with a condensate drain and a cleaning hatch for inspection. If the flue is undersized or blocked, I say so before the install rather than after. I fill and pressure test the system, bleed it thoroughly, run a first firing with the owner present, set the valve and pump curves, and explain load sizes, tank charging and the cleaning routine. Anything involving gas equipment — a gas backup boiler, a gas line, a gas meter — is connected only by the authorised utility service, never by me.

What the job includes:
• heat loss calculation and boiler and buffer tank sizing;
• boiler room layout, mounting, pipework and insulation;
• anti-condensation loading loop with a three-way valve;
• safety group, expansion vessel, pumps, dirt separator;
• chimney inspection, connection, cleaning hatch and draught check;
• connection of heating circuits and controls;
• pressure test, first firing, commissioning and owner training.

Typical timing is five to nine working days for a private house, depending on whether the boiler room is ready and how far the pipe runs go.