Signs Your Hot Water Cylinder is Working Too Hard (and Wasting Your Money)

Your unvented hot water cylinder is designed to deliver hot water reliably and efficiently. But like any system, it has limits. When it’s overworked, there could be subtle (or not-so-subtle) signs that it’s struggling. Not acting now can push up energy bills, shorten the lifespan of your cylinder, and even leave you without hot water when you need it most.

Here’s how to spot an overworked system and what you can do about it.

1. Hot Water Cylinder Running Constantly

If your cylinder seems to be heating all the time, even when you’re not using much hot water, it’s a clear sign that there’s something wrong. Constant reheating could mean that:

• The expansion vessel is undercharged

• Valves are leaking or not closing properly

• There’s limescale build-up that’s affecting the immersion heaters

What to do: Call a G3-qualified engineer, like EasyFlow, to check your valves, pressure settings, and any scale-related issues. A quick inspection can restore efficient operation and reduce energy waste. Note that you can avoid many of these issues with an annual maintenance agreement. Not sure what one should include? Contact the EasyFlow team to learn more.

2. Regular Tundish Drips

The tundish is your system’s early warning system, so it’s important to pay attention to it. If water is frequently escaping through it, your cylinder is constantly losing hot water, which it then has to reheat. That’s also a sign that there’s something else going on, and the cylinder needs to be inspected.

What to do: Make sure you check the tundish every week. Persistent dripping usually means the problem’s the pressure relief valve, expansion vessel, or combination valve, and it needs professional attention.

3. Strange Noises

Are you hearing hissing, gurgling, or banging sounds from your cylinder? They’re annoying, but they often mean that there’s something wrong inside. Scale deposits, trapped air, or pressure fluctuations can all cause these noises.

What to do: Don’t ignore them. Have an engineer inspect the cylinder, flush the system if necessary, and make sure the valves are working correctly.

4. Higher Energy Bills

A sudden jump in your energy costs can be a clue that your cylinder isn’t as efficient as it could be. Overheating water, repeated reheating, and leaks all contribute to higher electricity or gas usage.

What to do: Track your bills alongside your hot water usage. If things spike without an explanation, it’s worth having your system serviced. Small fixes can give you some pretty noticeable savings.

5. Temperature Fluctuations

Inconsistent water temperature (too hot, too cold, or running out quickly) means that your cylinder is struggling to keep a stable supply.

What to do: Check the thermostat settings, make sure your blending valves are functioning, and book a professional service if the problems persist.

Keeping Your Cylinder Healthy

Regular maintenance is the key to avoiding most of the problems we’ve talked about. Annual servicing, limescale management, expansion vessel care, and keeping an eye on the tundish all help keep your system working correctly. By being proactive about maintenance, you’ll reduce energy waste, prevent expensive repairs, and keep your hot water reliable.