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Autovents - Radiator Bleed Valve - Non Replaceable
Autovents - Radiator Bleed Valve - Non Replaceable Autovents - Radiator Bleed Valve - Non Replaceable

Autovents - Radiator Bleed Valve
Non Replaceable

Brand: Aladdin
Product Code: 24474
Brand: Aladdin
£6inc VAT
RRP: £8.00
You save: £2.00

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Key Product Info
  • No more manual venting
  • Keeps the radiators hot to the top
  • Save heating and energy costs
  • Guarantee: 5 Years
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  • Guarantee Length
    5 Year


  • Aladdin Autovents automatically bleed air and improve efficiency of radiators, heating systems and underfloor heating networks.
  • No need to manually bleed radiators
  • Keeps radiators and heating systems fully heat generating and efficient
  • Drains air from underfloor heating networks
  • Reduces heating costs
  • Avoids tenants calling out service engineers just to vent radiators
  • Aladdin Autovents are loved by homeowners and landlords.
  • They offer a stylish and efficient alternative to having to manually expel air from radiators.
  • Aladdin Autovents improve overall heating system efficiency. A standard radiator with just 2” of air can be up to 75% inefficient.

Inside the Bleed Valve


Aladdin Autovents save energy, keeps radiators hot to top,reduce corrosion and system noise, and dispense with the need for radiator keys.

Landlords like them:

As they reduce the risk of damage caused to systems by tenants failing to bleed air from radiators, as well as the cost of call-outs from those tenants who call out service engineers when air builds in a radiator.

For installed “problem” radiators:

Often systems have a problem radiator in which air collects; most often the towel rail. The symptoms are a cold top bar and the noise of bubbling water. The correct Aladdin product (check the thread size of the radiator) can be installed without draining the system. Just shut off the two water valves, release the pressure in the radiator via the existing manual vent, and use a spanner to take out either the manual vent or the blanking plug before installing the Aladdin valve. Open the water valves and the radiator will then bleed itself.

For new installations:

An increasing number of professionals believe Aladdin’s Hygroseal™ products more than pay for themselves in time-saved in new installations. The installation of new or replacement radiators traditionally has required the time consuming task of running from radiator to radiator to bleed air out as the system refills. Further, water out of the tap contains about 17% air by volume which separates naturally within the system over time and, in a system without Aladdin’s valves, would necessitate the regular bleeding of radiators for the first two weeks of operation at least. Some installers now fit Aladdin’s products on every radiator they fit to save time and money.

Although a perfectly designed and engineered central heating system should not collect air from outside the closed system:

  • New water out of the tap contains about 17% absorbed air by volume, which must be drained off from a closed central heating system as and when it separates;
  • Not all systems were perfectly designed in the first place, and many systems have been adapted with, e.g. new radiators fitted;
  • Many plumbers think that some compression and press-fit plastic fittings can suck in air on the suction side of the pump;
  • Corrosion in the system, e.g. inside pressed steel radiators, can result in the formation of gasses.

Fitting Aladdin Autovents helps by automatically eliminating gas and air from radiators which increases the efficiency of central heating systems from two perspectives:

  • Fitting Autovents extends the effective life of systems components: Autovents automatically bleed air and gasses from radiators which reduces corrosion and its consequence, the formation of sludge, which in turn extend the life of pumps, automatic valves, etc.
  • Because fitting Autovents reduces the volume of air/gas in radiators it helps maintain their thermal efficiency, therefore reducing the fuel requirement.
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How do I find out the size of my radiator tapping?

With a 1/2" BSP thread, the threaded hole in the tapping at the top of the radiator is approximately 20mm diameter - you should be able to fit your index finger in the tapping. The plug screwed in to the tapping will either be a chrome hexagonal valve, or a 'plug' with a square cavity in it. If you are uncertain or for smaller tappings please contact your radiator's manufacturer.

Can I fit Autovents to a new system?

Yes, on newly installed closed systems there will be a small pressure drop over the first 2 weeks or so as dissolved air separates from the fresh water (around 17% by volume), but any further pressure drop would be due to loss of system water (leaks). Some installers are priming a newly installed system to about 10% more than its operating pressure to compensate on a system fitted with Autovents.

What if the Hygroscopic™ Autovent is not venting?

The first time radiators fitted with these Hygroscopic™ Autovents are filled the air hisses out until water hits the hygroscopic washers and then they seal (you will often see a small 'bubble' of water after the first fill). If more air/gas builds up in the radiator, it will not escape until the hygroscopic washers have dried a little and have shrunk enough for gas/air to escape. The time it takes for the hygroscopic washers to dry and shrink varies according to ambient temperature and humidity: see the table in the Technical Details on the Product Page. So please, give this valve time to dry, before contacting us.

Can I vent the Hygroscopic™ Autovent manually?

Yes. Cartridge version: by loosening the cartridge slowly until you can hear gas/air escaping. Cartridge-free version: by using a spanner to loosen the whole valve slowly until you can hear gas/air escaping.

Air collecting in a radiator can be an early indication of a leak in the central heating system. Should I be worried that fitting an Autovent will mean that I spot a leak later?

  • On a pressurised system: Air can enter the system through micro-gaps in joints etc., without a leak, but in some cases a leak could lead to air collecting in one radiator, and in those cases fitting an Autovent might delay the identification of a leak. On such systems, NLB recommends that Autovents should be fitted to installed radiators that have a history of collecting air, and only after a careful inspection of the system has not identified any leak.
  • On a header-tank system: After the air absorbed in the water has separated, the best early indicator of a leak is a drop in pressure of the system, and an Autovent should, if anything, lead to a faster drop in pressure so an even earlier indication of a leak.

When do I know when to replace my Hygroseal cartridge?

If after a minimum of 5 years, the radiator starts getting cold at the top, the cartridge may require replacing in order to continue venting automatically. It is worth manually venting in case it is simply a case of the radiator running cool for a long period, and then seeing if the valve starts venting automatically again.

Can I fit the valve to a piping 'spur' at a system high - point?

Yes, provided the temperature of the piping allows the valve to operate at 35°C for the Hygroseal vent.

Does the Autovent work on Closed and Open systems?

Yes, on newly installed closed systems there will be a small pressure drop over the first 2 weeks or so as dissolved air separates from the fresh water (around 17% by volume) , but any further pressure drop would be due to loss of system water (leaks). Some installers are priming a newly installed system to about 10% more than its operating pressure to compensate on a system fitted with Autovents.

On a Closed system will fitting automatic vents cause the pressure to drop to zero and the boiler stop operating?

The answer is linked to the above - continual venting will be due to new air entering the system (through micro-gaps in joints etc.). Once the fresh water has vented its 17% of absorbed air the volume of water cannot further reduce in size - so if you still experience pressure drop it's due to water loss, i.e. a leak, which will require to be cured.

Can the valves work on negative pressure systems?

On about 1 in 400 systems air may be drawn in to the system where either (a) there is a radiator close to the suction side of the pump or, (b) where a radiator is higher than the water tank, in which case when the pump stops running a vacuum forms (e.g. in loft conversions).The Hygroseal valve has a semi-one way valve fitted already as standard, and will work on negative pressure systems.

Don't all automatic de-aeration valves leak?

No. Aladdin Autovents do not leak. They are guaranteed to operate for 3 years, and guaranteed leak-free for life. They contain a patented mechanical valve that positively closes when water gets to the internal mechanism of the valve. The Hygroseal™ range has a 5 year replacement guarantee.

Can corrosion inhibitors be used with an Autovent?

Yes. Fitting the Autovent should reduce the need for corrosion inhibitors as all your radiators will be free of air, but we do recommend their use because corrosion leads to further gas collecting in the radiators. To allow inhibitors to be used ensure at least one radiator still has a manual vent plug fitted at the opposite end to an Autovent, as this will allow the inhibitor to be injected.

Can leak-stop products be used with the Autovent?

Leak-stop products can jam valves in certain circumstances. We do not recommend their use.

Common Technical Plumbing Terms, Explained Simply

There are a lot of industry-specific terms that tend to be used by plumbers, and even when shopping for designer radiators and heating solutions you may find yourself confused with some of the terminology used.

Read our handy article on Common Technical Plumbing Terms to help clear up any confusion.

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