As the first chilly mornings arrive, the boiler coughs, radiators only run warm, and every autumn the tradespeople see a surge of emergency calls for avoidable breakdowns. For specialists in air conditioning and plumbing, the message is clear: before winter, a few simple checks are enough to prevent discomfort, unnecessary energy use and risks to the installation. It remains to know where to start and what to check.
Experts in air conditioning and plumbing summarize the priority in one clear directive: “Make sure to follow these steps to guarantee optimal operation,” they explain. Valves open, no leaks, correct pressure, purging of radiators, thermostat properly placed… This checklist, echoed by Spanish and French professionals, helps prepare without stress the boiler restart before winter. A routine of a few minutes that can avert many unwelcome surprises.
Restarting the Boiler: The First Checks to Do Before Winter
Even before pressing the start button, professionals recommend a visual inspection. It’s important to verify that all supply and return valves are open, that pipes and radiators show no signs of moisture or drops on the floor. A leak, even small, ends up damaging the installation. Radiators should also be kept clear, with no furniture, curtains or clothes resting on them.
The circulation of heat through the rooms also plays a key role. A radiator wedged behind a sofa or a thick curtain mainly heats the wall, not the room. Experts also advise taking advantage of the winter sun by raising shutters and opening curtains during the day, then closing them in the evening. This simple habit reduces the need to call on the boiler before winter.
Boiler Pressure and Radiator Bleeding: the Settings Pros Recommend
Another essential point: the boiler pressure. On the pressure gauge, most manufacturers recommend a value between 1 and 1.5 bar for normal operation, a guideline recalled by the Confederation of National Associations of Installers and Fluids (CONAIF). Too-low pressure prevents proper circulation of hot water, radiators stay lukewarm and the boiler may enter safety mode.
When a radiator is hot at the bottom but cold at the top, or when it makes gurgling sounds, trapped air is often the culprit. “Bleeding the radiators is a fundamental task for the proper functioning of a heating installation, because air presence can affect efficiency and raise energy consumption,” stresses Mario Rial Axpe, head of the technical department of CONAIF. He advises turning off the heating, slowly opening the bleed valve, and waiting for the air to escape. “Keep the valve open until water comes out steadily; that is how you know the intervention has been carried out correctly. In this way, the radiator releases the air it contains,” explains the CONAIF spokesperson, before adding that the pressure on the gauge should then be rechecked.
Thermostat, Temperature and Safety: The Final Steps for Optimal Heating
Once the boiler and radiators are set, the specialists turn attention to the room thermostat. It should be placed away from a heat source or a draft, or the measurement will be distorted and the boiler will be triggered too often. For comfort, they recommend a temperature around 21 °C, with each extra degree adding about 7% to the bill.
They also highlight the value of thermostatic valves and programmable thermostats, which adjust heat to the rooms and the times and offer, according to the cited studies, energy savings of 8 to 13%. Safety also matters: ensure ventilation openings are clear, consider a carbon monoxide detector, and call a professional if the pressure regularly drops or if some radiators stay cold.
