Common Hot Water Cylinder Problems

Enjoying hot water

Homes with a System or Regular boiler need a hot water cylinder to store the hot water produced by the boiler. They play an important role in making sure that your home has enough hot water for when you need it.

Hot water cylinders are normally very reliable but from time to time they might hit a bump in the road. We’ve put together a list of the most common hot water cylinder problems to help you find out what could be causing the issue.

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First of all, it’s important to know which type of hot water cylinder you have. There are two different types: vented and unvented.

Vented Hot Water Cylinder

A vented cylinder requires a supply of water from a large tank of cold water in the loft. Thanks to gravity, the water travels down a vent pipe to the hot water cylinder which is often found in an airing cupboard.

As water expands when it’s heated, the vent pipe also acts as an escape route for any excess water from the cylinder.

Unvented Hot Water Cylinder

Unlike vented cylinders, unvented cylinders don’t require a cold water tank in the loft because they’re directly connected to the mains. As the cylinder is receiving a direct flow of water the pressure should be stronger.

While vented cylinders have a vent pipe to deal with any excess water, unvented cylinders don’t. To deal with any excess water as it heats and expands unvented cylinders have safety features built into them. This will either be an expansion unit at the top or an air bubble that gets added during the installation.

Common Hot Water Cylinder Problems

No Hot Water

If your system is powered by a gas boiler then you need to check that the boiler is igniting. In the case that the pilot light is out and it won’t reignite, you will need to contact a Gas Safe registered engineer.

Should the system be powered by electricity (an immersion heater) then you need to check that your power supply is functioning. It might also be the case that the RCD (residual current device) has been tripped by another circuit in the house.

Not Enough Hot Water

During colder months, the system might have to work even harder to heat up the same amount of water as it usually would. The first thing you should check is that the temperature setting on your cylinder is correct. If that doesn’t do the trick then your cylinder might not be big enough to meet the demand.

It’s also worth checking that the cylinder isn’t leaking which could greatly reduce the efficiency of the system and needs to be repaired by a fully qualified engineer.

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Water is Too Hot

Before trying anything else, make sure that the temperature has been turned down; if the water is still too hot then there could be an issue with the temperature pressure relief valve not shutting off when it reaches the set temperature. This fault can be particularly dangerous because steaming or boiling water could start coming out of your taps; a heating engineer will need to be contacted to repair or replace the valve.

You will also need a heating engineer if there’s any sign of boiling from within the cylinder.

Discoloured or Smelly Water

Depending on whether you’re experiencing this issue with both cold and hot water, just hot water or just cold water, the possible cause will be different.

  • Cold and hot water or just cold: The cylinder won’t be causing this problem and the issue will stem from the mains supply.
  • Hot water: Hot water that’s discoloured or has a dodgy smell can be the result of the cylinder’s anode rod and water with a high concentration of sulphates. To resolve this, the cylinder may need to be flushed or have its anode replaced.

Strange Noises

Water in the cylinder will expand as it’s heated so you might hear the odd creak or gurgle from inside. Over time, these noises can become increasingly frequent as sediment like limescale builds up and creates blockages. A regular flushing of the system by a professional engineer helps to prevent build up and keep the system flowing smoothly.

No Water at All

In the case that you’re not getting any water at all, hot or cold, then there could be an issue with the filter. The most likely cause of a fault with the filter is that it’s blocked, which you’ll need an engineer to resolve.

Problems with Your Hot Water Cylinder?

If you’ve noticed that your boiler is experiencing one of the issues that we’ve mentioned above (or another problem) then you will need a qualified heating engineer to assess and repair the fault to get your hot water cylinder back up and running.

At Boiler Guide, we can put you in touch with up to 3 qualified engineers in your area that will all provide quotes, allowing you to pick the engineer that you’d like to carry out the work. Our service is completely free and best of all, there’s no obligation whatsoever.

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