Boiler maintenance before the season, not during it

Boiler callouts cluster in the first genuinely cold week of the year. That is not bad luck. It is the annual service being scheduled for autumn, when engineers are already busy, and the plant being asked for full output before anybody has proved it can deliver.

Do the annual work in summer

Move the service to the quietest month you have. You get better engineers, better prices, and a fault found in July is an order rather than an emergency. This one scheduling change removes more winter callouts than anything else on this page.

The annual service, in outline

• •Combustion analysis with the readings recorded, not just an adjustment made
• •Burner strip, clean and nozzle or electrode replacement as the readings justify
• •Heat exchanger and flue ways cleaned and inspected
• •Safety controls proved: pressure, temperature, low water, flame failure, and the time each takes to act
• •Expansion vessel charge checked with the system depressurised, which is the step most often skipped
• •Flue integrity and the room ventilation openings, which get blocked by stored goods

Monthly, in season

• •Operating pressure and temperature, written as numbers
• •Any lockouts since the last visit, and what caused them
• •Water level and feed operation on steam plant
• •Visible leaks at pumps, valves and joints
• •Combustion air openings clear

Water treatment is the long game

Most premature boiler and heat exchanger failures come from water quality rather than from firing. Scale reduces efficiency and then destroys the heat exchanger. Oxygen corrodes the system from inside. Neither shows up on a monthly walk round until it is expensive.

Sample and test on the interval your treatment programme sets, record the results as numbers, and look at them as a trend. Two years of readings tells you whether the treatment is working. One reading tells you nothing.

Statutory work is separate

Pressure systems, gas safety and insurance inspections carry their own required intervals and their own certificates, and they sit outside the maintenance schedule you are free to tune. Keep them marked as such, keep the certificates where somebody can find them in a minute, and diary the expiry rather than the inspection.

Before the first cold week

Run the plant at full output for an afternoon in early autumn, with somebody watching. Every fault this finds is one you get to fix in normal working hours, at a normal price, with the building still warm.