0808 250 9949 Make an Enquiry

Experts in Unvented Cylinders

Unvented cylinders are becoming more and more popular across the UK, especially in larger new builds as they are a great way to store pressurised hot water, ensuring you have a consistent hot water supply. However, they don’t come without their problems, so it’s important to stay on top of regular maintenance and servicing to ensure you always have a hot water supply.

Metro Plumb’s teams of expert plumbers are available across the UK to help with any unvented hot water system issue that you may have. Whether it’s an annual service or an emergency fault, we’ll be there to help. Our local, expert plumbers are available 24/7/365 across the country, so you can have peace of mind that there’s a plumber near you.

Noticed a problem with your cylinder or hot water supply? Then give us a call on 0808 250 9949 or fill out the form today and we’ll be happy to help!

Unvented cylinder servicing, repairs & replacement

No matter the model of cylinder, our highly trained plumbers can maintain, repair and replace every aspect of the system to make sure it’s working perfectly.

Pressure issues

Water temperature issues

Leaking pipework

Faulty or broken systems

Hot water tank repair or replacement

Airlock issues

Strange noises coming from the system

Limescale build up affecting hot water

Water supply issues

The History of Unvented Cylinders

Unvented cylinders for hot water storage first started being used in the late 1800s, however, there were many risks associated with these cylinders so they weren’t a popular option. Once the UK government made the appropriate legislative changes to allow the safe use of unvented cylinders in 1986, the demand for these unvented hot water storage cylinders rose significantly.

Now many properties have unvented cylinders, particularly large properties where a combi boiler cannot provide enough hot water for the demand; but many people with these cylinders aren’t aware of the risks associated with them if they are left without a service. Furthering this, it’s highly recommended to service your unvented cylinder at least once a year, and this may even be written into the terms and conditions of your home insurance policy and the warranty of your cylinder.


The Common Faults and Risks of Unvented Cylinders

Possibly the most common fault with unvented cylinders is a lack of hot water, shown either with cold water coming out of the hot water tap or no water flow at all. There are a few reasons for this error occurring, mainly due to either a tripped circuit breaker stopping the power supply to the cylinder or a problem with the residual current device on the unit. Another similar issue which can arise is problems with the thermostat, this is installed on the cylinder to monitor the temperature to prevent overheating, overpressure and prevent burns.

Other issues can occur with the pressure relief valve. These valves are installed to vent excess pressure caused by hot water, if these valves fail, the pressure could build up causing the tank to split, rendering it unsafe to use. Another valve on the cylinder is a pressure-reducing valve, these help to keep the incoming water pressure at a safe level, if these valves fail, the cylinder could become over-pressured and unsafe.

If you notice any of the above problems with your unvented cylinder, get in touch today. Our expert G3-qualified plumbers are available across the UK to help.

How it works

Our local, professional plumbers are highly trained, fully insured and DBS checked, with an excellent first-time fix rate. So you can rely on them to get your plumbing problem sorted in no time.

Metro Plumb calendar

Book a local plumber, 24/7 365, at a time that suits you.

Metro Plumb quote symbol

You’ll get a fast, fixed price, no obligation quote.

Metro Plumb plumber icon

Our expert plumber will arrive to carry out the work.

Why Metro Plumb?

We are a national plumbing company with over 40 depots across the UK and we’re dedicated to putting the needs of our local customers first. Your satisfaction is our number one priority, in fact, the majority of our work comes as referrals from happy customers, which is testament to our level of service.

Call 24/7/365

24/7/365 Availability

High quality symbol

Highly qualified local plumbers

Metro Plumb quote symbol

Fixed local prices, no obligation quotes



Frequently Asked Questions

Can any plumber work on an unvented cylinder?

No, only G3-qualified plumbers can work on unvented cylinders due to the increased risks associated with this type of hot water storage. Metro Plumb has G3-unvented plumbers across the UK to help.

How can I tell if I have an unvented cylinder?

Unvented cylinders don’t rely on a water tank in the loft, if you don’t have this tank then you will most likely have an unvented cylinder. Another way to tell is to look for an expansion vessel next to your tank. These are small tanks used to protect your tank from high pressure. If your tank has one of these then it’s an unvented cylinder.

How can I tell if I have a problem with my unvented cylinder?

The most common telltale sign is no hot water, either through cold water coming out of the tap or no water at all. Other signs include strange or loud noises coming from your system, extremely hot water or even water that has a funny smell to it

Can I upgrade my open-vented cylinder to an unvented cylinder?

Yes, it is possible to change from one system to another, however, it is not recommended to do this yourself. Only a G3-qualified plumber should complete any work on an unvented cylinder. It’s also not an easy like-for-like swap and you will need a lot of your heating system replacing when making this change. Although this is going to be costly, it may end up being more cost-effective for you in the long run and will give you better water pressure throughout your property.

Need some help and advice?

Our teams are experts in all things plumbing – so here they share some of their tips, guidance and advice with you.

Should I Turn My Boiler Down?

With energy bills showing no sign of dropping any time soon, you’ve probably been googling how to save on gas. While some will...

How To Handle Frozen Pipes This Winter

Winter walks, and hot chocolates by a warm fire – winter is certainly a beautiful season. However, plummeting temperatures can...

How to Increase Your Water Pressure

If you’ve ever tried to wash an abundance of shampoo out of your hair using just a trickle of water from a shower head,...

How Often Should You Get a Gas Boiler Service?

Having a gas boiler in good working order ensures a warm and comfortable home, a constant supply of hot water – and the safety...

Who Are Metro Plumb?

Has a pipe burst under your kitchen floor? Does your toilet refuse to flush? Is a dripping tap driving you to distraction? If you...

Our Partners McDonald Water Storage

Here at Metro Plumb we are always looking for companies to partner with, so that we can offer our customers the best possible...