With the first cold mornings, a boiler coughing and radiators that only feel lukewarm, every autumn tradespeople see an influx of emergency calls for avoidable breakdowns. For air conditioning and plumbing specialists, the message is clear: before winter, a few simple checks are enough to prevent discomfort, excess energy use, and risks to the installation. The catch is knowing where to start and what to inspect.
HVAC and plumbing experts summarize the priority with a clear directive: “Make sure to follow these steps to guarantee optimal operation,” they explain. Open valves, no leaks, correct pressure, bleed the radiators, thermostat properly placed… This checklist, echoed by professionals in Spain and France, allows stress-free preparation for the restart of the boiler before winter. A routine of a few minutes that can prevent many unpleasant surprises.
Boiler Restart: The First Checks to Do Before Winter
Even before pressing the start button, professionals advise a visual inspection. You should check that all supply and return valves are open, that pipes and radiators show no signs of moisture or droplets on the floor. A leak, even minor, will eventually damage the installation. Radiators should also be kept clear, with no furniture, curtains, or clothes resting on them.
The flow of heat throughout the rooms also plays a key role. A radiator jammed behind a sofa or a thick curtain mainly heats the wall, not the room. Experts also recommend taking advantage of the winter sun by raising blinds and opening curtains during the day, then closing them in the evening. This simple habit reduces the need to rely on the boiler before winter.
Boiler Pressure and Radiator Bleeding: The Adjustments Referred by Pros
Another essential point: the boiler pressure. On the manometer, most manufacturers recommend a value between 1 and 1.5 bar for normal operation, as noted by the National Confederation of Installer and Fluid Associations (CONAIF). A pressure that is too low prevents proper circulation of hot water, radiators stay tepid, and the boiler may go into safety mode.
When a radiator is hot at the bottom but cold at the top, or when it makes gurgling noises, trapped air is often the culprit. “Bleeding the radiators is a fundamental task for the proper functioning of a heating system, because the presence of air can affect efficiency and increase energy consumption,” says Mario Rial Axpe, head of the technical department of CONAIF. He advises turning off the heating, gently open the bleed valve, and wait for the air to escape. “You must keep the valve open until the water exits steadily; that is how you know the operation has been performed correctly. In this way, we ensure the radiator expels the air it contains,” adds the CONAIF spokesperson, before reminding that you should then recheck the pressure on the gauge.
Thermostat, Temperature and Safety: The Final Steps for Optimal Heating
Once the boiler and radiators are set, specialists invite you to look at the room thermostat. It should be placed away from a heat source or a draft, to avoid skewing the reading and triggering the boiler too often. For comfort, they recommend a temperature around 21 °C, as each additional degree adds about 7% to the bill.
They also emphasise the value of thermostatic valves and programmable thermostats, which adjust heat by room and by time and offer, according to cited studies, energy savings of 8 to 13%. Safety matters just as much: clear air vents, a potential carbon monoxide detector, and seeking a professional if pressure often drops or if some radiators remain cold.
