Common Boiler Problems & How to Fix Them
Posted July 10, 2025 | by T H Williams | Category: Heating
Boiler acting up? No hot water or strange noises? Boilers are the heart of the home when it comes to heating and hot water, but when they start misbehaving, it can cause real disruption. Below is a breakdown of the most common boiler issues we come across – and some safe DIY checks you can carry out before calling in a professional.
1. No Heating or Hot Water
This is one of the most common complaints. It could be due to:
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Low pressure (check the pressure gauge – it should sit around 1–1.5 bar)
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Broken diaphragm or airlock
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Thermostat issues
What you can try:
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Check and top up the boiler pressure if it’s too low.
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Ensure your thermostat is on and set to the correct temperature.
If that doesn’t sort it, it’s time to get it checked by a Gas Safe engineer.
2. Boiler Leaking or Dripping
Leaks can be caused by worn-out seals, broken components or corrosion in the system. It’s important not to ignore a leak as it could damage internal parts or your home.
What you can try:
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Switch off the boiler and isolate the water supply.
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Don’t open the casing – just monitor where it’s leaking from and call an engineer.
3. Strange Noises (Banging, Whistling, or Gurgling)
Odd noises usually point to air in the system, limescale buildup (kettling), or low water pressure.
What you can try:
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Bleed your radiators to release trapped air.
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Check the pressure – if it’s low, top it up using the filling loop.
Still making noises? You may need a system flush or descaling treatment.
4. Boiler Keeps Switching Off
This can happen due to low pressure, a faulty thermostat, or poor water flow.
What you can try:
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Check pressure and thermostat settings.
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Make sure your radiators are properly bled.
If it continues, it’s likely an internal issue needing professional attention.
5. Radiators Not Heating Up Properly
Are your radiators cold at the top and warm at the bottom? That’s usually air trapped inside.
What you can try:
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Bleed the radiators with a radiator key until water starts to flow.
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Check the boiler pressure afterward – it might need topping up.
When to Call a Pro
If you’re ever unsure or uncomfortable, always play it safe and call a qualified engineer. Some issues – especially anything involving internal components or gas – should never be tackled without proper certification.
Need help with your boiler in Liverpool or the surrounding areas?
Get in touch with T H Williams Plumbing and Heating today – we’re here to help with reliable repairs, servicing, and installations.