Vented Water Heaters

4 products

  • Dexpro Delux Over Sink Vented Water Heater

    Dexpro Delux Over Sink Vented Water Heater

    Dexpro Delux Over Sink Vented Water Heater

    £67.15 GBP
    £94.80 GBP -30%
    £67.15 GBP
    £94.80 GBP
  • Dexpro Delux Under Sink Vented Water Heater

    Dexpro Delux Under Sink Vented Water Heater

    Dexpro Delux Under Sink Vented Water Heater

    £95.00 GBP
    £95.00 GBP
  • DexPro Vented Mixer Tap & Hoses 3/8 fitting

    DexPro Vented Mixer Tap & Hoses 3/8 fitting

    DexPro Vented Mixer Tap & Hoses 3/8 fitting

    £40.80 GBP
    £57.60 GBP -30%
    £40.80 GBP
    £57.60 GBP
  • Monoblock mixer vented tap for Tudor undersink

    Monoblock mixer vented tap for Tudor undersink

    Monoblock mixer vented tap for Tudor undersink

    £141.53 GBP
    £188.70 GBP -25%
    £141.53 GBP
    £188.70 GBP

Vented water heaters, also known as gravity-fed systems, are a traditional and common type of hot water cylinder, particularly in older homes. The key characteristic of a vented system is that it is not sealed and relies on a cold water storage tank, usually located in the loft, to supply the cylinder.

Here is a breakdown of the primary categories of vented water heaters:

1. Direct Vented Water Heaters

These cylinders heat the water internally using one or more electric immersion heaters. They are a simple, self-contained solution for heating and storing hot water.

  • How they work: The cylinder is filled with cold water from a storage tank in the loft. A thermostat controls the electric immersion heater, which heats the water directly inside the tank. The system is "vented" via a pipe that runs from the cylinder up into the cold water tank, allowing for the safe expansion of water as it heats and preventing pressure buildup.
  • Key Features:
    • Stand-alone System: Ideal for properties without a central boiler or as a backup hot water source.
    • Simplicity: Their straightforward design makes them less expensive to install and maintain compared to unvented systems.
    • Economy 7: Many models are designed with a second, lower immersion heater to take advantage of off-peak electricity tariffs (like Economy 7) for cost savings.

2. Indirect Vented Water Heaters

These cylinders rely on an external heat source, such as a boiler, to heat the water inside the cylinder. They are the most common type of vented cylinder in homes with a central heating system.

  • How they work: The cylinder contains a coiled pipe called a heat exchanger. Hot water from an external source (e.g., a gas boiler) is pumped through this coil, which transfers heat to the domestic water in the cylinder without the two liquids ever mixing.
  • Key Features:
    • Energy Efficient: The overall efficiency of the system is tied to the efficiency of the boiler.
    • Solar Compatibility: Some indirect cylinders have an extra coil to connect to a solar thermal system, allowing for the use of renewable energy.
    • Backup Option: They can also be fitted with an electric immersion heater as a backup, ensuring a hot water supply even if the boiler fails.

3. Combination Cylinders

This is a space-saving variation of the vented system, designed for smaller properties or those with limited loft space.

  • How they work: A combination cylinder integrates the cold water storage tank and the hot water cylinder into a single unit. The cold water cistern is located at the top, and the hot water cylinder is below it. The system is still gravity-fed, but the all-in-one design eliminates the need for a separate tank in the loft.
  • Key Features:
    • Space-Saving: Reduces the space needed for a full vented system.
    • Easy Installation: Simplifies installation by combining two components into one.
  • Limitations: The reduced height difference between the cold water tank and the outlets can result in a lower flow rate than a standard vented system.

The Defining Characteristic: Gravity-Fed System

All vented water heaters are fundamentally defined by their reliance on gravity to create water pressure. Water from the cold water storage tank in the loft flows down to the cylinder due to the force of gravity. This means:

  • The water pressure at the taps and showers is low, and its strength depends on the height difference between the cold water tank and the outlet.
  • The system is "open" or "vented," with a pipe connecting the cylinder to the cold water tank, which acts as a safety vent for any pressure created by heating.
  • They are often cheaper to install and maintain but may require a pump to boost the water pressure for a more powerful shower.

FAQs

  • Why is the water pressure so low from my vented water heater?

    Vented water heaters, by their nature, rely on gravity to create water pressure. The pressure at your taps and showers is determined by the vertical height difference between the cold water storage tank in your loft and the outlet. The smaller this height difference, the weaker the pressure will be. Unlike unvented systems, which use mains pressure, vented systems can't provide a powerful, invigorating shower without the addition of a shower pump.

  • Can I connect a vented water heater to my mains water supply?

    No, a vented water heater must not be connected directly to the mains water supply. They are specifically designed for low pressure, and a direct connection to mains pressure could cause the cylinder to burst, posing a significant danger. The "vent" pipe that connects the cylinder to the cold water storage tank in the loft is a critical safety feature that allows for the safe expansion of water as it heats.

  • How do I improve the water pressure from my vented system for a better shower?

    The most effective way to improve shower pressure from a vented system is to install a dedicated shower pump. This pump is installed after the hot and cold water supplies leave the cylinder and cold water tank, respectively. It actively boosts the flow of water to the shower, providing a much more powerful and satisfying experience. It is important to choose a pump that is compatible with your specific system and plumbing.

  • Why is my vented hot water cylinder not heating the water?

    If your vented hot water cylinder is not heating water, the cause depends on whether it is a direct or indirect system.

    • Direct System (Electric): The most likely cause is a fault with the electric immersion heater or the thermostat. You should check if the circuit breaker has tripped and, if not, call a qualified electrician to inspect and replace the faulty component.
    • Indirect System (Boiler): The issue could be with the boiler, the pump that circulates hot water, or the thermostat on the cylinder. You should check if your boiler is working correctly and that the programmer is set to heat the hot water. If the problem persists, you should contact a qualified heating engineer.
  • How can I save money on my water heating bills with a vented system?

    There are several ways to improve the efficiency of a vented system:

    • Insulate the Cylinder: Adding an insulation jacket to the cylinder can drastically reduce heat loss and standby energy consumption.
    • Insulate the Pipes: Insulating the hot water pipes will ensure that the water stays hot as it travels to your taps.
    • Use an Economy 7 Tariff (Direct Cylinders): If you have a direct electric cylinder, a second immersion heater at the bottom of the tank can be used with an off-peak electricity tariff (like Economy 7), heating the water overnight when electricity is cheaper.
    • Keep the Thermostat Low: Setting the thermostat to 60°C is recommended for safety and to prevent the growth of bacteria, but going above this doesn't significantly improve performance and only increases energy consumption.