Boilers - what types are there?

There are three particular type of boiler installations available in today's market and these are combination, system and open vented. if you have central heating in your home then you will certainly have one of these types of installation, this will vary from home to home. 

What is an Open Vented Central Heating System?

A central heating system is called open vented if there is an open vent pipe which is bent over the top of a feed and expansion tank (F&E tank). The F&E tank is often called a header tank. It allows water to be added to the heating system to keep it topped up and it accommodates the expansion of the hot water.

In an open vented type of central heating system there is a small water tank which is usually in the loft. It is always higher than the highest radiator. The F&E tank has a pipe carrying the mains water supply which enters through a float valve at the side of the tank near the top. There is another pipe called a vent which is bent over the top of the F&E tank. The vent pipe has an open end. This forms part of an open vented central heating system. There is a third pipe near to the bottom of the tank which is connected to the central heating system. The F&E tank allows water through the float valve to flow down this third pipe to add to the central heating system to keep it topped up. This is how the feed and expansion tank feeds the system.

When the central heating is switched on, the water in the heating system gets hot and expands and takes up more space (it has a bigger volume). As the hot water expands it runs back up the third pipe (see above) into the F&E tank. This is how the feed and expansion tank allows for expansion (of water) in the system. The water in an open vented heating system is at a low pressure (typically 0.1 to 0.5 bar). The water contains additives and inhibitors which slow down the rate of corrosion of the boiler and the radiators. If there is no F&E tank, the central heating system is called sealed.

 

What is a sealed system?

A central heating system is called sealed if there is no vent pipe which is open to the air. If you do not have a feed and expansion tank in your loft, then you more than likely have a sealed central heating system.

Water can be added to the heating system to keep it topped up by using a filling loop. The pressure of the water in a sealed heating system is usually around 1 to 1.5 bar. The water in the heating system contains inhibitors which slow down the rate of corrosion of the boiler and the radiators.

The expansion of the hot water is accommodated by an expansion vessel. The expansion vessel can be anywhere in the heating system or can be inside the boiler. The expansion vessel allows the hot water in the heating system to expand while maintaining the water pressure. If the water pressure in the heating system gets too high (above 3 bar) then a pressure relief valve will open and discharge water from an overflow pipe. If this happens it shows that there is something wrong with the system and professional advice should be sought immediately.

 

What is a combination boiler system?

 

A combination boiler (also called a combi) provides hot water for central heating radiators and also heats water as it is required for hot water taps and showers. There is no need for a hot water cylinder (compare this with a heat only boiler) or for water storage tanks in the loft (which frees up loft space for other uses).

A combi boiler is part of a sealed central heating system. The boiler usually contains the pressure gauge and expansion vessel. It may have a temperature control on the front panel. In a property with a combi, cold water at mains pressure (high pressure) runs to all of the cold taps, showers, toilet cistern and other services. Cold water also runs through a pipe to the combination boiler which heats it as it flows through the boiler. The heated water runs through pipes to all of the hot outlets, taps and showers.

The water system with a combi boiler is called a high pressure system because all of the pipes contain water at a high mains pressure. The hot and cold water is at the same high pressure but the flow rate of hot water through the taps and showers may not be constant if more than one outlet is used simultaneously. This this can be a problem for showers. There are two types of combi boiler, the instantaneous combi and the storage combi.

Underfloor Heating

Heat Logic are accredited installers for Polypipe underfloor heating systems.

 

History of UFH

Underfloor heating was first introduced by the Romans over 2,000 years ago. Underfloor heating was used in most public buildings especially in the colder parts of the roman empire. The underfloor heating system, known as a hypocaust, was made up from ducts underneath the floor. The flues for these fires ran through the walls so that when the fires were burning the floors and walls heated the building. The furnace was laid round columns that supported the concrete slabs for the floor. The furnace was placed here so the draught would spread the heat under the floor then up through the walls heating rooms on the floor above to the chimneys. The roman underfloor heating was a lot of hard work to maintain with keeping the fire burning and cleaning the ashes this is why it was only for the wealthy. This type of heating system has recently been voted the most important heating invention ever by the British HVAC industry.

 

What is Underfloor Heating?

Modern warm water underfloor heating gives a near perfect room temperature profile between floor and ceiling due to a balanced combination of radiant and convected heat. Underfloor heating uses radiant heat which ensures you feel comfortable even at a lower air temperature than that produced by a conventional radiator heating system. 

Conventional radiator central heating producers the majority of its heat by convected air.  Convected air produced by radiators rises making the ceiling the warmest part of the room. Underfloor heating produces 50% of its warmth using radiant heat, this means all the floor is evenly heated, this is then absorbed by objects (sofas etc) in the room. Radiant heat gives you the ideal comfort conditions warm feet and a cool head.

When you walk into a room controlled by underfloor heating, you will be able to feel the difference almost immediately. Underfloor heating can be used with almost any floor covering these include carpet (below 1.5 Tog), lino, hardwood, laminate and stone. Stone based floor covering give the best results because they allow the heat to transfer easily. Unlike carpet an underlay which has  insulation properties and does not transfer heat as easily as stone or tile. 

 

Underfloor Heating in an extension, conservatory, cellar or basement.

If you are thinking of extending or refurbishing your home, an underfloor heating system is an ideal solution. New extensions and conservatories usually use screed or concrete as the floor structure warm water underfloor heating forms part of this floor structure and is built to last. With underfloor heating you will be able to get the most out of your new extension or conservatory the most comfortable heating system which gives you all-year round use.Underfloor heating single zone kits are designed to work independently from the rest of the heating system. This sort of heating system is works perfectly in conservatories and cellar conversions as these rooms need to be heated at different times from the radiators in the rest of the house, conservatories need to be heated independently to comply with Part L of the building regulations.Cellar conversions have usually have no solar gain this means while the rest of your house may be warm due to sunlight your cellar may still want heating as this is underground and usually cooler. This means you require a heating system that can control these areas independently, cellar floors are normally a concrete which means underfloor heating is a perfect solution for a cellar conversion.

Central Heating

Getting a new central heating system might seem easy right? Just choose the models you like and let the heating engineer get to work. Unfortunately, it’s not as simple as that. There are so many factors to consider before you decide on a heating system, and even more when you select an installer. By having a general idea of how central heating works, you’ll be better able to identify the right system for your situation. This means a better decision, saving plenty of headaches and money along the way.

Your system consists of these main parts: boiler, pipes, radiators, water storage tanks, and heating controls. The exact components needed will depend on the type of system you choose. The boiler takes water provided by your mains pipe and heats it. Burning gas or oil is the most common way to power the boiler. The heated water will either be pumped to a hot water storage vessel or directly to a water tap—this depends on whether it is a combination (combi) boiler or not.

The boiler also transports the water to radiators located throughout your home. The hot water travels through the radiators to release its heat energy, warming up the room. Once the heat transfer is completed, the now colder water circles back to your boiler for reheating once again.

If you decide to install a new central heating system for your home, you might be surprised about the number of factors that help determine your final bill. Since your system should match the characteristics of your home, it’ll be a bespoke heating solution—the price will reflect this.

There are so many different brands and models available, meaning that the prices will vary significantly. The most common scenario is that your central heating installer will design your system to ensure the best price for you; some homeowners may want to purchase the items themselves and whilst this may give them the impression that it can save them money, it mostly doesn't mean the case at all as often there are components purchased that are not needed and some that haven't been purchased that are needed resulting in higher labour costs and downtime.

Furthermore, whilst it might seem like a saving buying a new boiler "off the shelf" for around £350, the old saying must be remembered "you get what you pay for", there's always a reason why they are cheap, frequently with very short warranties. More often than not, boilers purchased on your behalf by a qualified Gas Safe Registered installer are more likely to carry a long manufacturer warranty of up to ten years which will include parts and labour.

Central heating installation costs will vary depending on the size of your home, your heating demand, and the type of system you choose. Households that require a high level of heating need a higher capacity boiler, as well as more radiators and piping, driving up costs. Certain boiler types, such as a conventional or system boiler, need expansion vessels and water storage tanks. This increases the supply and installation costs.

As you can see, all of these factors influence each other, making the whole process of pricing your new central heating system even more complicated. Luckily, you don’t have to work through this complexity on your own as we will discuss and take good care in providing you with the right system for you.

 

Is it time to get new central heating?

This is a question that you might be wondering about. Actually, there are many possible reasons why it might be time to switch to a new central heating system.

Age: Your entire system might be a few years old now and is in need of a revamp. Usually, you should replace your boiler after 10 to 15 years, and if the rest of your heating is reaching the end of their lifespan, it’s time to replace.

High repair cost: Occasionally, the price to fix a problem with your heating is much higher than it is to replace the whole system altogether. If this type of recommendation is coming from your heating engineer, you should consider installing a new system.

Low efficiency: Perhaps you have noticed that you are spending way too much on heating. This could be a result of an inefficient heating system. Upgrade to a modern, more efficient system to unlock savings for your energy bill.