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 Unvented Cylinders Repairs, Megaflo Servicing

in  St Albans AL1 AL2



Megaflo are the only manufacture to design a unvented hot water cylinder that has a built in expansion vessel, making Megaflo the go to company for neat, clean & space saving. For more information click the image to find out more on what we can install for you.

Range Tribune & ThermaQ make fantastic unvented hot water tanks for a lower cost than brans such as Megaflo. With external expansion vessels. for more information click  the image to find out more about what we can offer you.


Unvented systems have to provide a means to accommodate the expansion of the water in the cylinder as it heats up. Typically, two such methods are used – an external expansion vessel and internal air bubble. The former is basically a trapped volume of pressurised air and is held by a rubber diaphragm within a steel vessel. This is linked by pipe work to the unvented cylinder and as water expands, it's pushed into the expansion vessel, compressing the air within the diaphragm. Because the air is compressed, its pressure, together with that of the water in the cylinder, will increase. With the internal air bubble method, air is trapped in the top of the cylinder. The bubble compresses as the water expands similar to the way air is compressed in an expansion vessel. Annual servicing of the cylinder is needed to maintain the bubble. Local plumbers such as Abbotts Maintenance are experts in all plumbing work and can carry out annual services on all types of systems.

Unvented Systems Explained

There are two main types of water heaters used in residential homes today – vented and unvented. Even though vented systems are more common, unvented systems are still quite popular. They require less installation space and provide good flow rates to taps and appliances. Abbotts Maintenance experienced local plumbers have outlined the below guide explaining how unvented systems work.

Unvented hot water cylinders store water from the mains water supply. The water is heated either with heat from a boiler or using other electrical heating elements. This provides high pressure hot water supplies to feeding outlets. The increased pressure helps deliver better quality showers without the need for pumps. With unvented systems there is no need for a cold storage tank which helps free up space and requires much less pipe work.

Mains Water Supply

As unvented cylinders work from the power of the mains water supply, the mains pressure and flow rate must be adequate. Supply pressure should be around 2 bars and able to supply the required flow rates. A pressure-reducing valve is needed on all unvented systems to control the pressure of the incoming mains water supply to a safe level. Good plumbers will check the pipe sizes and flow rate of the mains supply in addition to the pressure.

Safety Measure

Unvented Systems have two basic dangers that must be addressed. These are over-pressurisation and overheating. Over-pressurisation can be caused by a failed pressure reducing valve while overheating can occur if an unvented cylinder overheats and the water continues to increase in temperature and pressure until the cylinder can’t hold the pressure and splits. These dangers can be prevented by fitting an expansion relief valve and a temperature and pressure relief valve.

Qualified Gas Engineers & Plumbers St Albans AL1 AL2

It is important to note that unvented systems require the skills of a qualified plumber. To work on an unvented water cylinder, plumbers must be qualified to work on unvented heaters and be registered. This is because unvented systems require a skill sets. At Abbotts Maintenance we have qualified plumbers to carry out such work.

Should I bother servicing my boiler or repairing a boiler?

Abbotts Maintenance Boiler servicing & repair is essential since the colder climate requires frequent use of boilers during the winter months and sometimes, even during the summers. Using a faulty boiler is not only dangerous, but can significantly contribute to increased utility bills.

A boiler that is not functioning to standards specified by the manufacturer can cause gas leaks that are dangerous for both the occupant as well as neighbours around Abbots Langley. There is also the danger of carbon monoxide poisoning, which can be prevented by regular servicing of your boiler.

Why does a boiler need repair or servicing?

As with any other appliance, regular use of a boiler will lead to decreased efficiency and deterioration over a period of time. This occurs for two main reasons: as the boiler is used, excessive soot, which is a by-product of the combustion process, can coat the inside components of the boiler leading to reduced efficiency, and the air-to-fuel ratio, which needs to be maintained for optimum performance, changes over a period of time due to component wear and tear. Boiler repairs & servicing is particularly important, since the boiler is being used daily almost throughout the year.

Abbotts Maintenance entails a service that will come to your home, clean the soot from your boiler and ensure that the air-to-fuel ratio is readjusted to optimize efficient running of your appliance. This will prolong the life of your boiler and will reduce the risk of expensive repairs in the long run.

Another critical reason to carry out proper maintenance on your boiler, is to prevent exposure to carbon monoxide, which, when inhaled over a period of time can lead to illness and even death. Incomplete combustion of fuels such as oil or gas in infrequently serviced boilers can lead to the production of carbon monoxide.

This gas is odourless and colourless and therefore hard to detect. Regular servicing can alert you to the presence of carbon monoxide and help keep you and your family safe.

Who will service my boiler and what qualifications should I check for?

At Abbotts Maintenance boiler repairs are carried out by a service engineer or technician who is specifically qualified to work on your particular type of boiler. All qualified service technicians should be Gas Safe Registered, all our engineers are. This is a certification that ensures that the engineer has been adequately trained to service your appliance from both a legal as well as a safety stand point.

Every Gas Safe registered engineer will have a Gas Safe identification card that will specify the company name and contact details, the engineers license number, whether he is qualified to work on domestic or commercial applications and his area of expertise – gas, LPG or oil boilers and other appliances.

There are several online services that allow you to check the credentials of the technician prior to permitting him to work on your boiler. Even though a registered technician might be more expensive, it is well worth the additional expense to ensure that the repair is carried out in a safe and professional manner, thereby preventing more problems in the future.

When and how often should I get my boiler serviced?

Abbotts Maintenance recommend servicing your boiler annually to ensure that it is running smoothly and to carry out any repairs that might be required in a timely manner.

By doing this potential problems can be detected early and repaired before they lead to bigger problems. It is recommended that regular servicing be carried out in the summer months, when boiler engineers are readily available so that the boiler is functioning well during the cold winter months when you will need to use it regularly.

Make sure you ask your technician for any safety tips; most technicians will also give you advice on how to maintain your boiler for superior performance and longevity.

What will the boiler engineer do when he arrives for the service?

The first task a technician will perform is a visual check to ensure that the running, fixing and positioning of the boiler complies with laws relating to installation, building codes, electrical, water and gas regulations laid out in the current legislation.

Next, the technician will fire up the unit to ensure that it is running properly and check for any faults before he opens the casing. Once the casing is opened, your service technician will check all the components of the boiler including the electrical parts, pipes, joints and interior surfaces for damage. He will also clean the inside surfaces of the boiler and readjust the air-to-fuel ratio to optimum values. If there are any faults, he will inform you of additional costs to repair or replace any parts.

Before replacing the boiler casing, he will carry out tests to ensure that there are no gas leaks. The entire process should take between 30-60 minutes, at the end of which you should receive a service report stating what checks and servicing the technician has performed.

Radiator Problems, Not Heating or as Hot?

Have a radiator that needs repairing, installing or moving? We regularly undertake all kinds of radiator work from issues with a lack of heat being produced, leaks from the connecting pipe work and re-fitting radiators that have parted from the wall. For a radiator not heating as it should could be due to rust- sludge in the central heating system and this will need power flushing.

Have you got a Leaking or Burst Pipe.

Water leaking from a fractured or burst pipe can cause extensive damage to your property if prompt action is not taken. That is why our fully qualified engineers are available to provide an emergency response, arriving on site to trace the source and resolve the problem as quickly as possible, ensuring that water damage is kept to a minimum. All of our plumbers are highly qualified and fully insured and all of the work they completed is fully guaranteed.

We offer an expert service, so call Abbotts Maintenance you can be sure of a local engineer in St Albans AL1 AL2, fast and quality service. Call us now!

Is your Leaking Tap driving you crazy.

Did you know that on average a leaking tap can lose up to 90 litres of water per week, costing you money and damaging the environment by increasing the amount of water that needs to be extracted from natural sites? We work on all kinds of tap whether it be mono bloc, mixer or conventional we can offer a complete repair in the majority of cases, limiting the money that the leaking water can cost you. In cases where a repair is not possible we can provide and install a new tap or fit a tap provided by you.

Do you have a Leaking Bath or Shower Tray.

Unfortunately in many cases a leaking bath or shower tray can only be identified once water damage begins to appear directly below the bathroom. But don’t worry, our specialist engineers can be on site within two hours to trace the source of the leak and repair the problem, limiting any further damage to your property.

Problem with your Shower not working.

Shower leaking or suffering from low water pressure?
There is nothing more frustrating than not being able to wash properly so give us a call and we can have an engineer onsite within two hours on average. You’ll be back to steaming hot, invigorating showers before you know it!

Is you Water Tank Leaking.

Water tanks are often sited in inaccessible locations within properties meaning that it can be difficult to identify an issue with the tank until the damage resulting from the problem becomes visible. A hidden leaking or overflowing water tank can be very destructive so we offer a priority service to our customers to prevent further damage to their property or belongings.

Need a new Appliance Fitted or Removed.

New washing machine, dishwasher or fridge freezer need fitting? We can make any necessary adaptations to existing plumbing to ensure that the new appliance fits and functions as it should and we can be with you within two hours on average or at an agreed time that suits you better.

Toilet Leaking or a Sticking Ball valve.

A leaking toilet can be an annoying problem to have, particularly if it is for public use on a commercial premises. That is why we carry out repairs to toilets and urinals in domestic, office, public houses and restaurants to ensure that the facility is fully working again as soon as possible and with the minimum of fuss. Do you find you have a noisy toilet after flushing? this is due to a poor ballvalve in need of changing.

Common Error codes.

Common fault codes on Worcester Bosch boiler range from EA 227 to E9. Vaillaint gas boilers have fault code like F75 low water to F26, F29 lack of gas or problems within the boiler. Baxi E119 low water E133 lack of gas.

Debit & Credit Cards

Abbotts Maintenance - local 24 hour emergency plumbers & Plumbing repairs 

All of our service engineers are highly qualified and fully insured and all of the work they completed is fully guaranteed. We offer an expert service, so call our Abbotts Maintenance Team ™ today and you can be sure of a local, fast and quality service.

Call us now on 0208 387 0155

General Services:

✔ Central heating installations ✔ Underfloor heating repairs ✔ Leaking radiator valves ✔ Emergency Plumbers ✔ Leaking toilets ✔ Boiler service & maintenance ✔ Boiler breakdowns ✔ Local Plumbers ✔ Leaking boilers ✔ Leaking washing machines ✔ Leaking dishwashers ✔ Gas engineers ✔ Radiators ✔ Boiler installation ✔ Boiler replacement ✔ Boiler servicing ✔ Thermostats ✔ Gas valves ✔ Circuit boards ✔ Drainage & waste pipe ✔ Blocked manholes ✔ Blocked drains ✔ Blocked toilets ✔ Blocked sinks ✔ Sani flo, Saniflo ✔ WC’s, ✔ Sinks ✔ Immersions ✔ Immersion Heaters ✔ Cylinders ✔ unvented cylinder ✔ Megaflo ✔ Sinks & Sani- Vite ✔ Shower repairs ✔ Electric showers ✔ Power Showers ✔ WC Cistern’s ✔ Syphon ✔ Boiler installations ✔ Boiler repairs ✔ Emergency plumbing ✔ Power flushing ✔ Corgi plumbers ✔ Emergency boiler repairs ✔ Gas safety ✔ Landlord certificates ✔ Gas safety checks ✔ Leaks, Burst pipes ✔ Outside taps ✔ Taps ✔ Cold water tanks ✔ Bathroom refurbishments ✔ Kitchen installations ✔ General Plumber Repairs ✔ Disabled bathrooms ✔ Disabled WC ✔ Fall heating systems

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