When living off-grid, there’s lots of complicated jargon out there surrounding the topic of heating oil, which is one of the most popular fuel choices for off-grid properties. And there's plenty about heating oil boilers and tanks too - which can be confusing at the best of times. For instance, you may well have seen the word 'OFTEC' on heating oil websites, but wonder what or who is OFTEC?’
Let us explain - quite simply, OFTEC is The Oil Firing Technical Association, and represents the oil heating industry in the United Kingdom. Their vision is for ‘all consumers to have safe and efficient heating’ and they have almost 10,000 registered technicians that are committed to working to industry best practice.
In this blog we’re going to make things simple – we’ve put together this quick guide to help you figure out what some of the terms relating to your fuel, your central heating oil boiler, and your tank, actually mean.
What is heating oil?
Let’s start by taking a look at heating oil and all the different names it's often called - it's also known as domestic heating oil, home heating oil, fuel oil, kerosene or 28 sec heating oil. It’s a type of heating oil that’s commonly used in domestic oil fired central heating systems throughout the UK. The term ’28 sec’ refers to the viscosity of the fuel, i.e. it’s a measure of the oil’s thickness or flow resistance, and indicates how quickly and easily the oil will flow through your system. 28-sec heating oil takes 28 seconds for a fixed amount of oil to flow through an orifice at a set temperature.
Just to throw in some further confusion, there’s also premium heating oil. This is essentially domestic heating oil with an additive added, which makes it a cleaner burning fuel and up to 15% more efficient than standard kerosene.
You may also have heard of 35-sec heating oil. 35-sec heating oil is another type of heating oil, but is slightly thicker and it takes 35 seconds for the same quantity of oil to flow through an orifice in the same conditions.
Most modern systems generally use 28-sec heating oil, although a few older systems might still run on 35-sec. It is important to use the correct grade of oil for your system to ensure optimal combustion and system performance, but if you’re in doubt, an OFTEC registered heating oil engineer will be able to help and advise.
Boiler confusion?
There’s more than one type of central heating oil boiler out there, so it’s good to know what the differences are, and which is most suitable for your home if you’re looking to replace yours. Crucial to the provision of warmth and hot water, each type is designed with specific needs in mind. Here we will take a look at the main types of domestic heating oil boilers:
- Conventional boilers: The most common type, these work by heating water within a heat exchanger which then circulates it through your central heating system to provide heat. They're also known as regular boilers, and the system will require a separate hot water cylinder which takes up space – not ideal in small properties where space is of a premium, but making conventional boilers more efficient at producing hot water than combi boilers. And a cold-water storage tank will be required - these are often located in lofts.
- Combination boilers: These type of boilers provide heating and hot water directly from a single unit. Often shortened to ‘combi’ boilers, they are compact units that work as both a central heating boiler and a water heater, as they heat water directly from the mains. So a hot water cylinder is not required which saves valuable space. Hot water is available on demand, and they’re often more efficient than conventional boilers.
- Condensing boilers: These boilers combine the functions of a heating boiler and a hot water boiler into a single unit. Similar to a combi boiler, they heat water directly from the mains supply, and they eliminate the need for both hot water cylinders and cold water storage tanks.
Confusing components?
Whatever the type of boiler, it will consist of several key components, some of which include:
- The burner – this is the part of the boiler where air is mixed with the heating oil and combusts. It generates heat to transfer to the boiler’s heat exchanger and needs to be kept in good condition.
- The heat exchanger – this is a metal chamber or coil where the hot combustion gases pass through, transferring the heat generated by the burner to the water.
- The expansion vessel – in some systems, an expansion vessel is used to accommodate the expansion of water as it heats up, and helping to maintain stable pressure within the system.
- The circulator pump – this component pushes the hot water out through the supply lines to circulate the heated water around your radiators, and then back again to your boiler for reheating.
- The pressure gauge – this indicates the pressure inside the heating system, and plays an important role in identifying any potential issues.
- The control panel – this houses various switches and indicators to allow control and monitoring of the boiler.
Keeping your boiler working efficiently is important, not just to keep you snug and warm, and with a ready supply of heating an hot water, but for safety and economy too. For more information, read our 5 top tips for keeping your heating oil boiler in tip-top condition.
Having your boiler serviced annually will ensure it’s running at its maximum efficiency and improves safety too, as your OFTEC registered heating oil engineer will check for potential carbon monoxide emissions.
Heating oil tanks explained:
Domestic heating oil tanks, also known as oil storage tanks, come in various shapes and sizes, and can be above-ground or below-ground tanks, plastic or metal, single-skinned or bunded. But just what do all these things mean?
Designed to store and hold heating oil for residential purposes as well as commercial or industrial heating systems, heating oil storage tanks are a crucial part of any oil-fired heating system. So let’s take a look at some of the most common types of heating oil tanks:
- Above-ground tanks: These come in different shapes for instance cylindrical or rectangular, and also in different sizes and are relatively easy to install and inspect. We would always recommend you choose a tank that is manufactured to OFTEC standards, and one that holds at least 1,000 litres of fuel for domestic use. Many heating oil suppliers charge a higher unit price for smaller quantities, such as for a 500 litre delivery.
- Factors to consider when choosing an above-ground heating oil tank are the amount of space you have available and how much home heating oil you’re likely to be using. If you’ll use a large quantity of oil, for instance, you may want to consider a large storage tank to avoid frequent refills. You’ll also need to comply with oil tank installation regulations, make sure there’s plenty of room around the tank for access so your tank can be filled safely and for maintenance.
- Underground tanks: These, as their name suggests, are tanks that are buried underground, and are usually made of steel. If you have limited space or want to keep your tank out of sight, they’re a great choice. However, installation costs are high, and they require regular maintenance and inspections.
- Single-skinned tanks: Generally the cheapest option, single-skinned tanks have one skin that the oil is held within, so just one layer between the oil tank contents and the outside word. Now less common than bunded tanks due to safety concerns, there is a risk of contamination in the event of a leak or damage to the tank occurring.
- Bunded tanks: Overall a much safer option for domestic heating oil users than single-skinned tanks, bunded tanks are basically tanks within a tank – the inner tank which holds the oil is surrounded by an outer protective layer known as the bund. The bund must be able to hold the contents of the inner tank plus an additional 10%. If the inner tank begins to leak, the spilled oil will be contained within the bund which acts as a failsafe, preventing environmental damage and providing protection against oil replacement.
Whatever sort of tank you have, proper maintenance is important and we would always recommend you have a regular inspection by an OFTEC registered oil heating engineer to ensure continued reliable operation of your heating system and to reduce the risk of environmental contamination due to an oil leak. For more information, take a look at our blog covering domestic oil tank installation and regulations.
We hope you find this jargon-busting information helpful, but if there’s anything we haven’t covered, we’re here at the end of the phone and happy to help.
Just give us a call on 01423 770 666 or email us at helpoil@northernenergy.co.uk