Vaillant boiler

How Old is My Vaillant Boiler?

Do you know how old your Vaillant boiler is? If you were the one to have it fitted, you can probably remember when that was. But if you have moved into a property that has a Vaillant boiler fitted, how can you tell and why do you need to know?

Find the age of your Vaillant boiler

All boilers have serial numbers. You will find this on the big white label either underneath your boiler or on the inside of the flip down plate, depending on the type of boiler you have. There are a lot of numbers here, but don’t worry, it’s easy to identify the date.
Vaillant serial number
The Vaillant serial number is the long number at the top of the label, 20 to 28 characters long. The 3rd and 4th numbers show the year the boiler was manufactured. The next two numbers show you the week in which the boiler was assembled. So in the image above, the 3rd and 4th numbers are 12, which indicates 2012. The next numbers, 14, show that the boiler was manufactured around the 14th week of that year, so March 2012.

Why do you need to know how old your Vaillant boiler is?

Age is a good indicator of how efficient your boiler is. Anything more than 10 years old will be using more energy and less efficient at heating. That means it will be costing you more money to do a less good job. Older boilers also have a higher chance of breaking down (and they never do that at a convenient time), and it costs more to maintain an old, inefficient system. So it might be time – and cost-effective – to consider replacing it.

What if you can’t find the serial number on your boiler?

If you can’t locate the serial number, don’t panic. There’s a handy list on the Building Energy Performance Assessment website where you can search by make and energy type. You could always check with Vaillant too.

Cloverleaf can help with all aspects of your Vaillant boiler, from finding the serial number and age, to fixing it or replacing it. We have been installing Vaillant boilers for more than 10 years and highly rate their reliability, performance and innovation. Call us today with your Vaillant or other boiler questions, or take a look at our Boiler Quote Wizard to get an idea of the cost of a new boiler.

solar thermal

Trustmark Accredited Solar Thermal Installer

Cloverleaf is proud to be a Trustmark accredited solar thermal installer. What does this mean? Well, we’ve been busy working towards accreditations to enable us to fit solar thermal panels. That involves being Trustmark accredited and MCS certified installers.

We achieved both just in time for the government to close the Green Homes Grant – literally the next day! But never mind, our accreditations still stand. And if you had already had a Green Homes Grant voucher awarded before 31 March 2021, you can still redeem it (within three months of its issue).

Are there any alternative green energy incentives?


Thankfully, yes. The government has an ambition that by 2020, 12% of heating comes from renewable sources. So it has extended its Renewable Heat Incentive scheme (RHI) until 31 March 2022. The aim of this is to encourage homeowners to install renewable heat technologies through financial incentives. Because of our recent accreditations, Cloverleaf is now qualified to design and install solar thermal. We are very relieved that there is an incentive still in place for the sakes of both the environment and us – it would be a total waste of all that training if we didn’t install any solar thermal!

What does it mean for you?

Any homeowner that has solar thermal heating fitted, and various other heat sources, is eligible to apply for an RHI. Take a look at the criteria to make sure you qualify. If you do, you will receive a payment every quarter for seven years for the amount of clean, green renewable heat your system produces. You can calculate the payments you will receive and the money you’ll save.

Ofgem RHI tarrif

Ofgem have produced these tariffs at a level designed to compensate for the difference between installing and operating costs of renewable heating systems and fossil fuel systems, based on 20 years of heat produced.

We’re really excited to be able to start installing solar thermal heating. You will need to use a Trustmark accredited solar thermal installer to qualify for an RHI so please give us a call to find out how we can help. We can give you a basic idea of cost and help you decide if solar thermal is right for you.

underfloor heating in kent

Underfloor Heating Installation in Kent: Case Study

Underfloor heating really is the future!

At the end of last year, we were contacted by Border Oak, one of our regular clients who build bespoke oak framed houses. One of their clients had requested this heating in their beautiful new home and so Border Oak got in touch with us. This particular project was in the lovely village of Sissinghurst in deepest, darkest Kent.

Installing underfloor heating in new build properties is an absolute no brainer! We get a lovely empty space to work in and there’s no upheaval for the homeowner. Plus the floor is prepared as part of the build. That means no additional stripping out or building works involved, which keeps the cost down.

What are the benefits of underfloor heating?

Its Important to mention there are two types, electric and water-based. We are talking about water-based systems because that’s what we fit.

Running costs: Cheaper to run than radiators due to the lower operating temperates required.

Versatility: Can be powered by a gas boiler very efficiently but ground source and air source heat pump technology are also a great match due to the lower flow temperature required. This means you do not need to be on mains gas to have wet underfloor heating.

Efficiency: Very efficient way to heat your home. Radiators heat the air around them but underfloor heating warms the entire floor surface, creating an even and ambient temperature throughout the space.

Aesthitics: Lets be honest, not all radiators are pretty. Underfloor heating can easily be designed to heat the entire space without the need for back up radiators at all. Leaving more wall space for what ever you choose.


We fit the systems, leaving them under pressure at 10 bar while the screed is laid. This allows a small expansion gap for the pipe to expand in the screed without causing cracking. Then it’s time for the flooring specialists to come and advise on the best floor surface for your room.

If you would like more information on underfloor heating, please read our post on Underfloor vs Radiators in the Knowledge Centre or call us for a free non obligation quotation which will include free design and consultation.

There’s no doubt this is the future, especially in new build properties.


Blog By Dean Dawe

Underfloor Heating installation

Working our way through installing the Underfloor Heating.

underfloor heating installation

Making sure every inch of the floor is covered.


The very orderly water fed pipes.

 new build property

Perfect Underfloor Heating project – a new build!

Boiler Quote Wizard

Covid-safe Boiler Quote with the Boiler Quote Wizard

Introducing the Boiler Quote Wizard!

There’s never a convenient time for a boiler to breakdown. And when it breaks down beyond repair, you will need a replacement as soon as possible.


Our Boiler Quote Wizard has been designed for people who are looking for an accurate boiler quotation, but without the disruption of a home survey.


Perhaps you can’t have engineers in your house right now. No problem. Use our Boiler Quote Wizard to get a quote without a site survey. It’s quick, efficient and accurate. We are one of the few boiler companies who can do this without a site survey. And we will honour the quote for up to 3 months.


You need just 10 minutes to complete the 10-step Boiler Quote Wizard and we will get back to you within 24 hours with a fully detailed quotation.

This quick and efficient process will fast track you to your new boiler before you know it.


  • This service is only for boilers that will remain in the same place as your existing. If you want to re-site your boiler, please contact us and we can advise. And, of course, if you would still prefer a face-to-face quotation, we would be more than happy to visit you.
  • If you’re thinking of replacing your boiler or looking for further information on the type of boilers we install, please visit our boiler partners at Alpha, Worcester Bosch, Vaillant and Viessmann.
Unvented cylinder in loft space

Is It OK To Put an Unvented Cylinder in the Loft? A Case Study

Before we start, it is important to point out that all Cloverleaf engineers are fully qualified to work on and install unvented hot water systems.

The G3 qualification proves competence and allows us to register the cylinder with building control on completion of the job. We can also raise a building regs compliance certificate. When you come to sell the house, this is worth its weight in gold. It’s proof that you have employed a competent person to do the job and that it has been signed off with building control.

Let’s say you have decided, hopefully with our help, to opt for an unvented cylinder over a combi boiler. There are many installation considerations which I will highlight in this post. We’ll not go into detail about why you should or shouldn’t have an unvented cylinder, but discuss if it’s ok to put one in your loft space.

One of the downsides of an unvented cylinder is that it still takes up valuable space! So one of our most popular conversions from a low pressure system to a high pressure system is to hide the cylinder in the loft. But what are the perils of putting 200L litres of hot water under pressure above your head? And how do you do it safely?

Consideration 1 – Weight and height

Water is heavy! 1 litre of water weighs 1 kilo so a 200 litre cylinder of water can easily weigh 250kg when full up. That’s a quarter of a tonne!

The first thing we check when surveying is if there’s a supporting wall directly underneath the proposed cylinder location. This is very important because this amount of weight can actually bow ceiling joists if the weight is not supported adequately.

If we are taking a cold water tank out, it is very likely the tank has already been sited with a supporting wall below. But we never take this for granted.

Once you find yourself a nice supporting wall, we are then looking for decent head height so the cylinder can stand up. This can sometimes have an impact on the size of cylinder you end up with. There are cylinders available now that lay on their side, so this is a problem we can usually work around.

Consideration 2 – How big?

I think all plumbers have done this once in their lives. Turned up to a job with a cylinder that’s perfect for the customer’s needs. But it doesn’t fit through the loft hatch! Cylinders do come in all shapes and sizes. Getting it through that small, square hole has to be high on the list of things to check first. And definitely before committing to a cylinder in the loft.

Again this is something we would check at the survey stage. Loft hatches can be made bigger at very little expense, so don’t write the idea off until we’ve checked it.

Consideration 3 – Frost

When all your hot water is sitting above your heads, it is well worth mentioning the dreaded burst pipe.

If all your pipework in the loft has soldered fittings and is fully lagged, there really shouldn’t be anything to worry about. Unfortunately, so often this is not what we find when we pop our heads into customers’ lofts. On our travels we see some absolutely horrific plumbing. And usually the catalyst to a new water feature in your bedroom is very cold weather.

On the survey, we look for how well the roof is insulated and how easily outside temperatures would penetrate the loft space.

The cylinder is already well insulated so it comes down to the thickness of the pipe insulations. We also aim to remove plastic push fit fittings anywhere on the installation. This dramatically reduces the risk of anything leaking in the event of sub-zero temperatures.

Consideration 4- Discharge Pipe

What happens when you heat water under pressure? It wants to expand and escape. This is the primary reason why unvented cylinders are built a lot stronger than conventional cylinders.

Unvented cylinder regulation is very tight in this country. There are many safety devices fitted as part of a correct install to prevent the cylinder from ever getting into an explosive state.

The downside of all this safety is that a discharge pipe has to travel from the cylinder to a safe termination point at low level. This does sometimes put people off having an unvented cylinder. The pipe needs to be at least 22mm and made of copper. Not always a pretty sight.

We have done some clever installs though. We have run the pipe internally and drilled it out of the wall at the last minute. This avoids any pipe showing on the outside. But in the majority of cases, there will probably will be a copper pipe coming down the wall somewhere. Best I prepare you for it now! This is again something that is considered at the survey stage.

The regulations do say we are allowed to terminate the discharge pipe into a waste pipe. We would only do this as a last resort if there is no feasible route for the copper discharge to travel to a low level point outside.


And that is all I have to say on the matter for now.

I hope that my comments have been useful. If you are thinking about unvented hot water in any shape or form, please use the contact form and we’ll get back to you.

I would be very happy to discuss your requirements over Zoom or FaceTime until we are out of this lockdown situation.

Green Homes Grant

Green Homes Grant Accredited Installer

You may have heard that the UK Government has launched a new scheme, The Green Homes Grant. This grant could give you up to £10,000 to make energy efficiency improvements to your home.

There are certain criteria to be met – you must either own your own home (including a park home on a residential site) or be a residential landlord in the private or social rented sector. Once eligibility criteria is reached, the vouchers issued will cover either two thirds of the cost of energy efficiency improvements to your home, or up to a maximum government contribution of £5,000.

If you, or someone in your household, receive certain benefits, you may be eligible for a voucher covering 100% of the cost of the improvements. The maximum value of the voucher is £10,000. Check here to find out how much you could get.

The scheme is now open for applications. It’s extra exciting for us. As from 1st  February 2021, we will gain our MCS and Trustmark accreditation for solar thermal technology, which is one of the qualifying primary low carbon measures. This means we can accept your Green Homes Grant voucher to put against a solar thermal installation – designed and fitted by us, of course.

Despite the new accreditation, we are not newbies to solar thermal. In fact, we have actually been fitting it on and off for years. However, it hasn’t taken off in the way we wanted it to or hoped it would and so held back on MCS accreditation. The rest of our services have kept us very busy in the meantime.

We believe the introduction of the Green Homes Grant, together with ever increasing pressure to reduce carbon emissions, shows willingness from the government to put their money where their mouth is. It has certainly been the catalyst for us to do a big push with this technology.

It always appears to be too little too late where climate change is concerned. But it’s a start! £2 billion, however, will not last long. So register your interest today and let us guide you towards a greener, low carbon future.

Please also visit our solar thermal page which has more information about the benefits of heating your hot water from the sun.

Latest Corona Virus update from us..


In such challenging times, we wanted to let you know how we are approaching the next few months.

Our first priority is ensuring the safety and well-being of our customers and colleagues.

However following the latest guidance and advice from the Government, we have taken the decision to fully restart non essential works in a stepping stone approach to

try and get the business back on track.

These are uncertain times for everyone and we do not know how long it will take to get things moving again.

We just want our customers to  know we are here and OPEN FOR BUSINESS!

As of 1st June 2020 we will be providing our full list of services again, however precautions will still be taken on every job to protect us and customers from the virus. Social distancing will remain in place as per the governments advice.

Do you have any of the following Issues you would like us to resolve in the near future? If so we’d love to hear from you!

  • Low mains water pressure
  • Poor shower pressure or broken showers
  • Noisy boilers
  • Boilers that need relocating
  • Unfinished building projects that need restarting
  • Underfloor heating projects
  • Leaking bathrooms
  • Radiators that don’t heat up fully or do not heat the room.
  • Ageing heating controls which are not working effectively
  • Excessive gas bills.

Just a few of the services we will be bringing back from the first of June !


We are still taking every precaution possible to prevent spreading the virus. Apologies if these steps seem rather drastic, but due to people losing their lives, we have set out 6 rules below to minimise contact and allow us to get back to work.


1.       Engineers have been instructed that they must self-isolate if they display any symptoms and will not be allowed to continue to work.

2.       We will be requesting customers to wait in another room while we carry out any repairs or at a safe distance to maintain the 2 meter rule.

3.       No handshakes on arrival.

4.       Please keep all members of the family, especially children away from the working space while we are on site.

5.       We will arrive with personal protective equipment such as gloves and face masks and anti bacterial wipes.

6.       If card payments are taken on site this can also be done at distance, the reader cleaned with anti bacterial wipes before asking you to enter your pin.


Please note if you are still unsure about our engineers attending your property to give you a boiler quote, we do have our Boiler Quote Wizard which was designed for busy people who are looking for an accurate boiler quotation without a survey.


Cloverleaf  will do everything possible to maintain heating and hot water where ever we are needed and endeavour to provide the best service we can under the circumstances . If you are currently self-isolating, or suspect that you might be suffering from Coronavirus, we ask that as a precaution you inform us when booking an engineer visit so that we can plan the most suitable approach.

Thank you to everyone for your patience and lets hope there’s some light at the end of the tunnel for local business and the country in general.

Dean MD



Corona Virus Update from us.

Whilst we are in the midst of the this awful Corona virus pandemic, we would like to let everyone know we are still available to carry out emergency works.

Due to reduced office staff, Dean is taking the majority of calls and responding to emails personally.

Is your situation a genuine emergency ?

If your enquiry is not urgent, such as a repair or if you are considering replacing your boiler, please use our contact page .

Since we have been in lockdown, many jobs have been priced successfully with good quality photographs that the customer has provided. We can then start your job immediately after the lock down.

Examples of emergency work are-

No heating, No hot water, Intermittent heating/hot water, Water leaks, Gas leaks or anything which is imperative to maintain a quality of life, or any works essential to maintain levels of hygiene.


We will take every precaution possible to prevent spreading the virus, however boilers do not stop breaking down and we would prefer to be on the road helping those in most need.

Apologies if these steps seem rather drastic but due to people losing there lives, we have set out 5 rules below to minimise contact.



1-Engineers have been instructed that they must self-isolate if they display any symptoms and will not be allowed to continue to work.

2-We will be requesting customers to wait in the garden while we carry out any repairs or at a safe distance to maintain the 2 meter rule.

3-No handshakes on arrival.

4-Please keep all members of the family, especially children away from the working space while we are on site.

5-We will arrive with personal protective equipment such as gloves and face masks and anti bacterial wipes.



How is Cloverleaf managing Corona virus ?

At this very scary and uncertain time.
We would like to let all our customers know we have put procedures in place to come into line with the current government advice!



This means we are still here to answer your calls and respond to emails.
Our office team are working from home but we have a modern phone system which allows us to transfer calls to each other as if we were still in the office.
There should be no noticeable difference felt from the customers perspective, we are still here working.
With regards to our large on site work this continues where there is no risk of coming into contact with other workers or groups of people.
We are either on very sparsely populated building sites or totally empty buildings.
Every precaution is being taken to not contract the virus or pass it on.
With regards to our call our work, please feel free to call us with your issues.
Please be reassured we are taking call out work on a case by case basis and trying to help as many people as we can over the phone.
We are only sending engineers out in the most urgent cases and when we do ensuring that we sterile hands before we enter and once we leave.
We are also equipped with masks and gloves. We will be taking this situation extremely seriously and the health and well being of at risk and vulnerable people is our main concern.


Whilst all this madness is going on, if you need a new boiler quote, why not give our new Boiler Wizard Tool a try.

It’s a 10 step process which will guide you through taking a set of photographs which will not require a site visit so Corona virus friendly.

It takes no longer than 10 minutes to complete the form.
Once submitted  we can provided a detailed and accurate quote to you email box within 24 hours. 
Due to the very uncharted territory we are in, we will happily honor this quote for 12 months so plenty of time to come out the other side of this health crisis and get back to some sort of normality. 


Let’s all try and do our bit to prevent the country going into lock down!
From all the staff at Cloverleaf, stay fit for as long as possible and we will do the same.
For the unfortunate people that have already got the dreaded Covid 19, we wish you a speedy recovery and just hope we can all see the back of this horrible virus as soon as possible.
Boiler pressure low

Boiler pressure dropping! What are the causes of losing boiler pressure ?

Boiler pressure low

Boiler pressure safety switch Vaillant Eco-tec.

A guide to why your system pressure  is dropping? Do not ignore this!

Boiler pressure dropping is something we encounter very frequently, especially during the heating season.

Central heating system which incorporate a pressure gauge and a filling loop are called sealed systems and should not lose pressure consistently.

Sealed system means exactly that!

Once all the air is bleed out of the heating system the pressure in the system should stay stable because the water has no where to go.

The central heating water circulates around the radiators and boiler every time you turn it on and unless you bleed a radiator or you have a leak the water has no way of escaping.

Boiler pressure dropping, what are the causes of system pressure lose?

The following steps will guide you through some basic steps to understand what is causing this drop.

If you cannot resolve this yourself using our guide below we are on hand to step in should you require some professional intervention.

1-You have a leak on your heating system!

You have a leak somewhere on the central heating circuit! This includes radiators, radiators valves and all connecting pipework.

Unfortunately this does sometimes mean pipework which is not visible, either underneath timber floors or screed.

Customer action! -Check all visible joints including radiator valves and connections for obvious signs of leaks. If you feel confident in doing so turn off the isolation valves for the heating circuit underneath the boiler as shown below. This will temporarily leave you without heating however this will prove whether your leak is on the heating circuit or boiler. If the pressure stays stable after shutting off the valves and you cannot find any obvious leaks then your leak is in the floor somewhere and you may require our assistance.


2-You have a faulty pressure relief valve!

You have a faulty pressure relief valve either inside the boiler or on an external pressure relief valve. Pressure relief valves are designed to let out excess pressure in the event of over pressure usually when the boiler exceeds 3 bar. When they fail they will leak water from the central heating system at a much lower pressure to a copper pipe terminated outside of the property.

Customer action!- Look externally for a small copper pipe exiting your property usually close to the boiler or cylinder location. This is the pressure relief pipe exiting to atmosphere.

You are looking to see if this is dripping while you have pressure in the system. If it is call us, this is not a DIY job.

3-You have a faulty expansion vessel

You have a faulty expansion vessel- This means your boiler pressure will exceed 3 bar during the heating up process.

This is because the expansion of water in the system has nowhere to go due to the expansion vessel failure. Pressure  increases exponentially with temperature so once  the pressure reaches 3 bar the pressure relief valve will expel the excess pressure from the system until it reaches a safe point. When the system cools down you will find the water lost will now show on the pressure gauge as a significant drop. Very similar to the above scenarios, as if the system has a leak and will also cause the boiler to lock out and break down once cooled.

Customer action!-Run the central heating system up to full temperature and check to see if the pressure gauge rises. If it does shut the boiler off immediately and contact us. Replacing an expansion vessel is not a DIY job either. It is also good practice to replace the pressure relief valve at the same time.

This is due to the wear and tear caused from the valve opening and shutting and may not reset once its been activated too many times.

4-The leak is inside the boiler!

The leak is inside the boiler! Weak points on boilers are as follows: Automatic air vents,  O rings joints, washers, divertor valves and heat exchnagers.

In most cases the boiler leak will eventually drip out of the bottom and be quite obvious but in not in all cases. Small Internal leaks do not always leak

out of the boiler because the drip may be dripping onto another surface which is catching the leak.

The leak can also be disguised by running down a pipe which may not be obvious or the leak can  evaporate while the boiler is hot.

Customer action!- If you see a leak coming from the bottom of the boiler turn the electrical supply off to the boiler immediately as the leak can very easy leak into the electrical control box of the boiler and inflict expensive damage. If you have followed all the other steps and by a process of elimination come to the conclusion that the leak is inside the boiler, call us.  We will service the boiler and provide a quote to repair the leak.

Do not take the case off of the boiler yourself in any circumstances as this may contravene Gas safety regulations.

5-You have bled the air out of your radiators!

You have bled your radiator system to remove air from the the top of a radiator. In turn this drops the system pressure and must be replaced by introducing fresh water into the system via the filling loop.

Customer Action!- If you have never done this before there are many You tube video tutorials.

Here is one for an Vaillant Eco-tec plus boiler which has an internal filling loop.

There are many to choose from including the tutorials from on our own You Tube channel.  Remember when re-pressurising a system after bleeding radiators, take care to not over presssurise the system.  To be on the safe side, stick to 1 bar of pressure and then monitor for two weeks to ensure you do not have any leaks on the system which may have lead to the air to build up in the tops of the radiators in the first place.

I hope this guide has been helpful.

If you do have further questions or would like a site visit please contact us. We are more than happy to provide advice over the phone which costs nothing.

Written by Dean Dawe MD