Turning the Heating On for Winter: Your 10-Point Checklist

Most boiler breakdowns we’re called to in late autumn have the same story: the heating hasn’t run for months, the first cold night arrives, and something that could have been spotted in September stops it working. Turning the heating on before you really need it gives you time to fix small problems at normal prices.

✅ The 10-Point Checklist

1. Do a test run now. Turn the heating up and let it run for an hour on a mild day. Every radiator should get warm. If the boiler won’t fire, you’ve found the problem before the engineers’ diaries fill up.
2. Check the boiler pressure. On most sealed systems the gauge should read about 1 to 1.5 bar when cold, rising a little when hot. Below 1 bar, top it up following your boiler’s instructions — see boiler pressure low. If it keeps dropping, there’s a leak to find.
3. Bleed radiators that are cold at the top. That’s trapped air. With the heating off and the radiators cool, open the bleed valve with a radiator key until water appears, then close it. Bleeding lowers the pressure, so check the gauge again afterwards.
4. Cold at the bottom or patchy? That usually points to sludge in the system, which bleeding won’t fix. It’s worth mentioning at your service. See radiator cold at the bottom or top.
5. Check the thermostat and timer. The clock may be an hour out after the clocks change, and batteries in wireless thermostats run down over summer. Around 18–21°C suits most homes; keep living areas at least 18°C if someone is elderly, very young or unwell.
6. Turn the radiator valves up. Thermostatic radiator valves (TRVs) left on low or “*” all summer can stick. Turn each one fully up and down a few times to free it.
7. Find the condensate pipe. The thin plastic pipe from a condensing boiler to the drain can freeze in a cold snap and stop the boiler. If it freezes, pour warm (never boiling) water along it, then reset the boiler.
8. Lag exposed pipes in the loft, garage or outside walls, and know where your stopcock is in case one bursts.
9. Test your carbon monoxide alarm and replace it if it’s past its end-of-life date. Watch for warning signs: lazy yellow or orange flames instead of blue, soot or staining around an appliance, or a pilot light that keeps going out.
10. Book the annual service. If it’s been more than 12 months, book before the cold weather. Many manufacturers’ warranties also need a yearly service.

🚨 Carbon Monoxide: Know the Signs

Carbon monoxide has no colour and no smell. Symptoms — headaches, dizziness, nausea, breathlessness and tiredness — are easily mistaken for flu, and they often get better when you leave the house.

If you suspect carbon monoxide: switch off the appliance if it’s safe to, open windows and doors, get everyone outside into fresh air, call 0800 111 999 and get medical advice. Don’t use the appliance again until a Gas Safe registered engineer has checked it.

💡 Run It Efficiently

• Combi boiler? The radiator (flow) temperature is often set higher than needed. Many homes stay warm at around 60°C, and lower in mild weather. Note the current setting first, lower it a little at a time, and turn it back up if rooms don’t get warm.
• Hot water cylinder? Don’t set the boiler below about 65°C — the cylinder must store water at 60°C or more to stop legionella bacteria growing. If you’re unsure which system you have, ask your engineer.
• Use the timer and TRVs to heat rooms when and where you need them, rather than turning the whole house up.
• Bleed and balance — a system without air and sludge heats up faster and uses less gas.

Not sure whether to stick with your current boiler? See combi vs system boiler or repair or replace.

📞 When to Call an Engineer

• The boiler won’t fire, keeps locking out, or shows a fault code that comes back after a reset.
• The pressure keeps dropping, or goes above 3 bar when hot.
• Banging, kettling or gurgling noises — see boiler noises.
• Any sign of carbon monoxide, soot or a lazy yellow flame.
• Water leaking from the boiler or any pipework.

Never take the casing off a gas boiler. Only a Gas Safe registered engineer may work on gas appliances.

🏠 For Landlords

• Heating and hot water are your responsibility — you must keep them in repair and working order, and a breakdown in winter needs a quick response.
• The annual gas safety check is a legal requirement. Booking it in the autumn, with a boiler service, catches problems before winter. See what happens during a gas safety check.
• CO alarms are required in any room with a fixed fuel-burning appliance such as a boiler or gas fire (not gas cookers), and must work at the start of each tenancy. See smoke and CO alarm rules.
• Give tenants a short winter note: how to top up the pressure, where the stopcock is, and how to thaw the condensate pipe.

🏆 Get Winter-Ready with FE Maintenance

• Gas Safe registered engineers across North, West and Central London
• Boiler service from £80 (system boilers from £90)
• Landlords: boiler service + gas safety certificate from £120, certificate emailed the same day
• Emergency call-out from £99, 7 days a week
• Free online client portal — every certificate stored in one place, with reminders before renewals. See how it works

Book a boiler service or ask for a quote.