No Heating in a Cold Snap: Emergency Steps

No Heating in a Cold Snap: What to Do Right Now

Waking up to a freezing house is more than uncomfortable — in very cold weather it can become a genuine risk, particularly for young children, elderly residents, or anyone with a health condition. Before you call an engineer, there are a handful of quick checks you can do yourself in under ten minutes. Work through them in order.

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1. Check the Thermostat First

It sounds obvious, but it is the most common cause of a sudden heating failure.

• Make sure the thermostat is set above the current room temperature — if it is set to 18 °C and the room is already 19 °C, the boiler simply will not fire.
• Check any timer or programmer on the boiler or a wall controller. A power cut or a clocks-change event can reset schedules without warning.
• If you have a smart thermostat (Nest, Hive, etc.), open the app and confirm it is connected and calling for heat.

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2. Check the Boiler Pressure

Low pressure is one of the most frequent reasons a boiler locks out and stops heating.

• Look at the pressure gauge on the front of the boiler. Most combi and system boilers need to sit between 1.0 and 1.5 bar when cold.
• If the needle is below 1 bar (or in the red zone), the boiler may have cut out as a safety measure.
• Most modern boilers can be repressurised using the filling loop — a small silver or grey braided hose underneath the boiler with one or two valves. Open the valves slowly until the gauge reads around 1.2 bar, then close them firmly.
• If you are unsure or cannot locate the filling loop, do not guess — call us and we can talk you through it, or send someone out.

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3. Try a Boiler Reset

If the pressure is correct but the boiler is showing a fault light or error code, a reset will sometimes clear a temporary lockout.

• Press and hold the reset button (usually marked with a flame symbol or the word Reset) for around three seconds.
• The boiler will attempt to fire. Listen for the ignition click and the sound of the burner starting.
• If it fires and then locks out again within a few minutes, stop resetting. Repeated resets on a faulty boiler can cause further damage. Note down any error code displayed and call an engineer.

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4. Check the Condensate Pipe (In Freezing Weather)

Modern condensing boilers produce a small amount of acidic water that drains away through a white plastic pipe — usually running down an outside wall or into a drain.

• In freezing temperatures this pipe can ice up, causing the boiler to lock out with a gurgling noise.
• You can carefully pour warm (not boiling) water over the external section of the pipe to thaw it, then reset the boiler.
• This is one of the most common call-outs during a cold snap and is straightforward to resolve.

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5. Check Your Gas Supply

• Try a gas hob ring if you have one. If there is no gas at the hob either, the issue is with your supply rather than your boiler.
• Check whether your gas meter has a emergency control valve that may have been accidentally turned off.
• If you suspect a gas leak at any point — you can smell gas, hear a hissing sound, or see a flame that will not go out — leave the property immediately, do not use any switches, and call the National Gas Emergency Service on 0800 111 999.

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6. Keep the House as Warm as Possible While You Wait

• Close doors to rooms you are not using.
• Use electric heaters if you have them, but never use a gas oven or barbecue indoors for heating.
• Lag any exposed pipes you can access to reduce the risk of a freeze.

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When to Call an Emergency Heating Engineer

Call us straight away if:

• You have worked through the checks above and the boiler will not stay on
• You have vulnerable people in the property — young children, elderly relatives, or anyone unwell
• The boiler is making unusual noises (banging, kettling, or a continuous gurgling)
• You can see water leaking from the boiler or pipework
• The error code on the boiler display is not clearing after a single reset

A heating failure in cold weather is not something to sit out overnight. Our engineers cover the full TW postcode area around the clock, including Twickenham, Teddington, Richmond, Hounslow, Feltham, Staines, and everywhere in between.

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Call Emergency Plumbers TW any time, day or night: 07725 479493

We will ask a few quick questions to understand the situation and get the right engineer to you as soon as possible.