Updated on 28th April, 2023 by Martin Astley
Hot water usage is widespread in the UK, especially in the winter. People heavily use hot water for cooking, bathing, cleaning, and central heating. Many people use a hot water cylinder to store the water and use it to get supplied with continuous hot water and heating on demand.
Many homeowners with a system or a regular boiler will be familiar with the hot water cylinder. If you have a regular or a system boiler, you should know about the basics of a hot water cylinder. If anything goes wrong with your hot water cylinder, it gets damaged or poorly insulated, and your heating and hot water supply will be disrupted. That’s why it is crucial to understand the functioning of a hot water cylinder and how it impacts your central heating system.
This article will shed light on a hot water cylinder’s type, components, and more. So, make sure to read this article to the end.
What is a hot water cylinder?
A hot water cylinder or hot water storage tank is used to store hot water in quantity so that it can be supplied instantly whenever needed. Furthermore, they are divided into two types: vented and unvented. Let’s discuss them in detail!
Different types of hot water cylinders
Ventilated hot water cylinder
Vented hot water cylinders require an external cold water storage tank, which feeds water to the cylinder after a boiler or immersion heater has heated it. The cold water storage tank is typically in the loft, requiring gravitational force to generate pressure. The heated water then travels down to the bottom of the hot water tank.
unvented hot water cylinder
On the other hand, unvented hot water cylinders do not need a cold water tank because the water comes directly from the mains at a higher pressure. They are becoming increasingly popular because they are small and don’t need external storage tanks, making them more space-efficient. However, they are more expensive to install and require additional items such as relief valves and twin thermostats.
As crucial as it is to understand the differences between vented and unvented hot water cylinders, It is also vital to understand direct and indirect hot water cylinders. So, let’s discuss the two!
Direct hot water cylinder
A direct hot water cylinder is not connected to a boiler and relies solely on an immersion heater to heat the water.
indirect hot water cylinder
On the other hand, an indirect hot water cylinder requires an external device, typically a boiler, to heat the water through a heat exchanger.
By comprehending the differences between the types of hot water cylinders mentioned above, you can now decide which is best suited for your needs.
Whether you’re looking for a more energy-efficient option or want to ensure a steady hot water supply, understanding these systems’ nuances is essential. So, before deciding, take your time, gather complete information, see what you need and what you don’t, and make the right choice!
Note: You cannot install a hot water cylinder with a combi boiler, as they don’t require an expansion tank. The storage tanks are only required for a system or a regular boiler.
Components of a Hot Water Cylinder
While a hot water cylinder may seem simple, several crucial components combine internally and externally to store and maintain hot water. You need to know about its features. Below we are going to discuss the hot water cylinder’s crucial components:
The tank is the structural foundation of the hot water storage cylinder. The tank is made of glass, and the steel outer lining helps keep the water hot for longer. Additionally, tank insulation is crucial to keeping the water hot for longer.
The drain valve is the passage that helps you drain the excess water when you want to refill your tank or replace it. Draining your tank is an excellent way to clean unwanted particles and debris out of the tank.
Pressure Relief Valve:
The pressure relief valve helps maintain the hot water temperature inside the tank. The valve enables you to relieve excess pressure from the tank and prevent the tank from bursting and flooding your home.
Thermostats are devices attached outside your hot water cylinder that let you turn on and off your heating from the boiler to the hot water cylinder. The ideal temperature to kill bacteria in your hot water tank should be 60–65 degrees.
The electric elements in hot water storage cylinders are known as immersion heaters. Usually, there is only one immersion heater, but sometimes there are two. The advantage of immersion heaters is that you can still get hot water when your boiler fails. However, I advise that you do not depend on immersion heaters entirely. Additionally, these elements are controlled by their thermostat and will only start when the temperature is below the pre-set temperature.
Wherever there is water, there is going to be corrosion. An anode rod is suspended within the tank to act as a sacrificial piece of metal, prolong the storage tank’s lifespan, and reduce deterioration over time. The anode rod is usually magnesium or aluminium with a steel core.
To maintain your hot water cylinders for longer, you must understand their components to ensure that your hot water cylinder functions optimally.
Common Problems with Hot Water Cylinders That Require Replacement
Hot water cylinders are essential to any heating system but can develop problems over time. Some of these common issues may require replacing your hot water cylinder.
While it’s normal for heating systems to make noise, screeching, gurgling, and sizzling sounds can cause concern. If you’re experiencing these noises, contacting a Gas Safe Engineer is best. They can perform a central heating power flush, repair, and inspection to identify and solve the problem.
Discoloured or Smelly Water
If you notice discoloured or smelly water coming out of your hot water taps, it’s likely due to corrosion and rust buildup in your hot water tank. An anode rod is installed in your hot water tank to attract corrosive elements, but it may need to be replaced if it’s overly corroded.
Too much Hot Water
If you’re getting extremely hot water, the temperature might be incorrectly set. Check the temperature setting on your boiler and adjust it accordingly. If you have a hot water cylinder that doesn’t have a vent, check the temperature pressure relief valve to see if there are any problems.
No Water Supply
If you aren’t getting water from your taps and showers, the problem might be a blocked filter. Internal blockages are caused by the buildup of sludge and debris. This is why you must involve expert attention and contact a Gas-Safe engineer. Before contacting him, check with your supplier and neighbour to ensure there isn’t any problem with the supplier network.
Frozen Condensate Pipes
Condensate pipes found in condensing boilers are responsible for draining acidic or contaminated water away. Condensate pipes are located outside the wall near the boiler and can get easily frozen in winters, restricting the flow of hot water and heating. The good news is that you will not necessarily need an expert’s help and can solve the problem yourself. For your assistance, we have written a detailed guide on defrosting a frozen condensate pipe, don’t forget to look.
When you are experiencing inconsistent temperatures from your central heating and hot water supply in your home, leakage might be the problem. If you suspect a leak, you will have to find it, but don’t try to fix it; instead, contact a gas safety expert and let him deal with it.
Low Boiler Pressure
Low boiler pressure restricts the flow of hot water. If you notice low pressure, check the heating pump, and bleed it out. If the pump is fine, try repressurising the boiler with the help of the boiler filling loop.
An airlock in the pipes
When water flows through your pipes, excess air and water vapour can cause airlocks, which restrict the flow of hot water to your taps and showers. This problem is prevalent in older central heating systems with a hot water tank and outdated pipework. Our detailed guide on removing an airlock from your central heating system provides step-by-step instructions to solve the issue and restore your hot water flow.
Benefits of a hot water cylinder
1. Fulfils high demand for hot water
A hot water cylinder is an excellent option if your home simultaneously demands an instant hot water supply for multiple bathrooms.
2. Compatible with Solar Power or Biomass Fuels
The water in the hot water storage cylinder can also be heated by solar power or biomass, making it an eco-friendly choice for you and your home. Besides being eco-friendly, using renewable energy reduces your carbon footprint and saves you money on energy bills.
3. Immersion Heater Included
An immersion heater is an electric heating device that manually heats the water in your storage cylinder if your boiler breaks down.
So if you have a hot water storage cylinder, you can enjoy the benefits of an immersion heater. But remind yourself that does not mean you should heavily rely on immersion heaters to get your boiler fixed or replaced as soon as possible.
4. Direct and Indirect Heating
Hot water cylinders let you heat water in two ways: directly and indirectly. This gives you more options and means you can choose the most efficient and cost-effective method for your home that best suits your needs.
5. Space-Saving Design
The hot water storage cylinder is highly space-efficient, as it can be easily stored in an airing cupboard. Additionally, if you go for an unvented hot water cylinder, you won’t need an external cold water storage tank, saving you more space.
How to use a hot water tank efficiently
It is essential to know how to use a hot water tank efficiently; otherwise, the purpose wouldn’t be fulfilled, and instead of saving money, you would be wasting it. Below, I am going to mention some tips to make sure you try them out:
- Set the thermostat to the recommended temperature of 120°F. By doing that, you can conserve energy and reduce your monthly utility bills.
- Ensure to insulate your hot water tank and pipes to minimise heat loss and energy waste. Due to poor insulation, your tank cannot keep the water warm for long.
- Make a habit of proper maintenance, including draining the tank of sediment build-up, checking for leaks, and ensuring that your hot water tank operates smoothly and efficiently for its entire lifespan.
- Additionally, consider installing low-flow fixtures or aerators, as they can increase efficiency and save money in the long run.
By following these steps, you can ensure that your hot water tank runs optimally while lowering costs and reducing its environmental impact.
How long should a hot water tank last?
If you maintain it properly and sincerely, it will last 10–12 years or even longer. If the situation arises in which you will have to replace your cylinder, remember to involve a Gas Safe engineer in your decision and make the final decision based on his call.
How much does a hot water tank cost?
The cost of a hot water tank varies depending on the type you choose. Let’s take a closer look at the options available and their associated cost.
- If you opt for a vented (direct) hot water cylinder, the cost will range from £200 to £400, including additional labour charges ranging from £30 to £80.
- On the other hand, if you choose a vented (indirect) hot water cylinder, the total cost will be slightly higher, ranging from £210 to £450, with an additional labour cost of £30 to £80.
- If you opt for an unvented copper storage tank, you can expect to pay around £200–550, with labour costs ranging from £30 to £60.
- Alternatively, if you prefer an unvented stainless steel storage tank, the cost will be higher, ranging all the way up to £200 to £2000, with an additional labour cost of £30 to £60.
It’s important to note that cost is not the only crucial factor when selecting a storage tank. You should also consider the tank’s size, the material it is made of, its energy efficiency, and any additional features that may be important to you.
To summarise, a hot water storage cylinder is a handy backup appliance that stores hot water for a day or two and works seamlessly with immersion heaters and solar panels. Knowing its components, compatibility, and benefits is essential before purchasing it.
With just a little maintenance and care, this appliance can last for years, making it a wise investment for any homeowner.
If you still have questions or need assistance, don’t hesitate to contact 24|7 Home Rescue at 0345-3192-247. Our team of experts is always available to help you find the right solution for your home.