Frequently Asked Questions

A bunded heating oil tank simply consists of a tank within a tank. The fuel is stored in the inner tank and the outer tank acts as a failsafe so that in the event of a spillage, excess fuel will collect in the outer tank - thus averting a pollution incident.

Bunded heating oil tanks have been proven to significantly reduce the risk of pollution at oil storage installations. They are a requirement at commercial, industrial, institutional and commercial premises; all installations in the Channel Islands; and, at most domestic installations in the United Kingdom and Republic of Ireland.

Single skin tanks on the other hand, consist of only one shell or skin. This means that in the event of a tank split, valuable heating oil will be lost, and the surrounding environment will be polluted by the heating oil contained within it.

Before purchasing an oil tank, it is worth consulting The Oil Firing Technical Association (OFTEC) for relevant information surrounding the storage of heating oil.



Not all domestic heating oil tanks are the same. Some are made from steel, some from plastic, some are thicker than others, some are single skin, and some are bunded. 

Firstly, you need to know if you want a steel tank or a plastic oil storage tank. Harlequin manufacture rotationally moulded plastic oil storage tanks as they are not susceptible to the same levels of corrosion as steel tanks. They are also lighter and easier to transport, not to mention being more economical.



Harlequin oil tanks are made from medium density polyethylene (MDPE). Materials and components used in the manufacture of Harlequin Oil Tanks are resistant to the potentially damaging effects of the liquids they are designed to contain. MDPE displays excellent chemical and impact resistance qualities. All Harlequin Oil Tanks are manufactured only from premium grade, virgin materials.



You also need to consider whether you wish to purchase a single skin oil tank or a 'bunded' oil tank. Single skin oil tanks are made using just one tank wall, i.e. the tank skin. Bunded oil tanks consist of a 'tank within a tank' design, which means that your oil and the surrounding environment are protected in the unfortunate event of the inner tank splitting. Single skin tanks are a more environmental hazardous purchase option, as no protection against tank splits and oil spills are offered.



Should your oil tank split and should an oil spill subsequently occur, the clean-up costs in such an event can reach as much as £50,000 and may not be covered by your home insurance policy.



Harlequin believes that the materials which it uses to manufacture its tanks, as well as the structural design of its tanks, make them the first choice for oil tank installers across the UK and Ireland.

Harlequin Oil Tanks are suitable only for the storage of:

Kerosene (C1/C2)

Agricultural Fuel Oil (A2)

Diesel (D)

Home Heating Oil

All Harlequin Oil Storage Tanks must be installed in accordance with supplied instructions, the requirements of OFTEC Technical Instruction Book 3 and prevailing statutory requirements. Please note that Harlequin Heating Oil Storage Tanks are not suitable for connection to a fuel delivery system incorporating a flexible hose and automatic trigger nozzle.

Top outlet bunded oil tanks are quite simply oil tanks which have the outlet to the burner placed at the top, rather than the bottom of the tank. Oil is then drawn out, as opposed to being gravity fed through the outlet at the bottom. All Harlequin bunded oil tank models can be provided as either top outlet (ITT) or bottom outlet (ITE) tanks.



Top outlet oil tanks are suitable for use with most pressure jet burners - we recommend installing a Tiger Loop de-aerator, to eliminate the need for a return line to the tank. Pressure jet burners are fitted to most oil boilers sold today in the British Isles.

Top Outlet Bunded Oil Tanks are not compatible with vapourising (or wick) burners, fitted to some oil-fired stoves. At such installations, a bottom outlet bunded oil tank should be fitted or else an oil lift device should be incorporated within the oil supply line.

If you are in any doubt as to the compatibility of top outlet or bottom outlet bunded tanks, consult the appliance manufacturer or OFTEC.

If the tank is less than 3500 litres in capacity, it should not be placed within 760mm of a combustible boundary e.g. a fence.

This distance assumes that there are no flu outlets or buildings between the tank and the boundary. Where these clearances cannot be achieved, the protection measures noted in British Standard BS 5410: Part 1: 1997 must be provided, by means of a 30 minutes fire-resistant wall - which extends at least 300mm above and beyond the ends of the tank.

For tanks with a capacity greater than 3500 litres of for fire barrier construction requirements, please contact OFTEC for advice.

Oil Storage Tanks with a capacity of less than 3,500 litres should not be placed within 1.8 metres of a flu outlet.

Where these clearances cannot be achieved, the protection measures noted in British Standard BS 5410: Part 1: 1997 must be provided by means of a 30 minutes fire-resistant wall which extends at least 300mm above and beyond the ends of the tank.

For oil tanks with a capacity over 3,500 litres or advice on constructing a fire-resistant barrier, please contact OFTEC.

Oil Tanks with a capacity not greater 3,500 litres should not be fitted any closer than 1.8 metres to non-fire rated (30 mins. minimum) walls or eaves.

Where these clearances cannot be achieved, the protection measures noted in British Standard BS 5410: Part 1: 1997 must be provided by means of a 30 minutes fire-resistant wall which extends at least 300mm above and beyond the ends of the tank.

It will be necessary to protect exposed eaves forming part of a roof within 1.8 metres of the top of an oil storage tank to provide a 30-minute resistance to fire. Cladding can be applied to the eaves in order to prevent fire spreading to the roof.

If the tank capacity is greater than 3500 litres or you require further advice, please contact OFTEC.

Your oil tank should be located 1.8metres from the nearest dwelling and 760mm from a boundary (e.g. wall or fence). If this is not possible, then a 30-minute firewall is required, which must extend 300mm above and beyond both ends of the tank. Your local building control authority can provide further advice.

Oil tanks should be maintained yearly, by an OFTEC certified tank installer. You can ask your tank installer to provide a tank check as part of your boiler service.

Do heating oil tanks manufactured by Harlequin have an OFCERT License?

Yes. Harlequin bunded oil tanks each have an OFCERT license, meaning they have gone through rigorous testing processes by industry body and leader OFTEC in order to gain approval for use.

Internal oil tanks should never be installed in a habitable area, and should always be contained within a specially constructed, purpose designed, enclosed chamber. Detailed requirements exist for the installation of oil storage tanks within habitable buildings and domestic garages.

Oil tanks should always be installed by a trained technician, preferably an OFTEC approved tank installer. We can recommend an OFTEC-certified tank installer as we work very closely with several installers. This allows us to recommend only the best and most reliable installer to our customers.

As a minimum, all plastic heating oil tanks should be installed on a flat, level, fire resistant surface, capable of supporting the weight of the tank when fully laden. Where concrete slabs are used, they should be at least 50mm thick.

The base should extend at least 300mm beyond the widest points of the oil tank and fully support the base of the oil tank in its entirety. Piers are not suitable for this purpose and will cause irreparable damage to the oil tank, resulting in premature failure and catastrophic product loss.

Detailed oil tank base requirements can be found within OFTEC Technical Instruction Book 3.

With our Harlequin ITE range of oil tanks, there are three types of gauges within the tank pack: 


Includes an Apollo standard oil tank contents gauge which comprises of a tank mounted transmitter unit and plug in receiver unit, along with a bottom outlet kit.  The tank transmitter constantly checks the level in the tank and transmits this to a plug-in receiver unit which displays the level on the easy to read LCD screen.

Includes an Apollo Visual oil tank contents gauge which comprises of a tank mounted transmitter unit and plug in receiver unit, along with a bottom outlet kit. Apollo Visual as well as reporting the fuel level to a plug-in receiver also has a built in LCD display on the transmitter incorporating an on-tank level.



Includes an Apollo Smart oil tank contents gauge which comprises of a tank mounted transmitter unit and plug in receiver unit, along with a bottom outlet kit. Apollo Smart Receiver Unit benefits from a mains power supply, and simply plugs into a standard socket, allowing you to monitor oil heating usage from almost any room in your home or office.

*Please note - Harlequin HQi range does not include a tank pack. 

All Harlequin oil storage tanks are manufactured from a material which incorporates UV inhibitors. These prevent ultra-violet rays from permeating the structure of the tank, thus preventing fuel degradation.

Harlequin oil tanks are the most secure tanks you will find in the market. All our bunded oil tanks are lockable at both the fill and inspection points. We also provide a range of added security accessories.

Water will form in any oil storage tank. It is perfectly normal and occurs as a result of the tank warming up during the day and then cooling at night. In single skin oil tanks it will collect in the base of the tank; in bunded oil tanks it may additionally collect between the inner and outer tanks. 

All bunded oil tanks should be inspected annually for the presence of water found to be present either inside the oil tank or in the case of bunded oil tanks, between the inner and outer tank. Failure to remove any condensation may result in fuel contamination and irreparable product damage.

Condensation can be removed by most oil tank installers, technicians and most fuel distributors. We can recommend an OFTEC-certified tank installer tank installer for you as we work very closely with a number of installers. This allows us to recommend only the best and most reliable installer to our customers.
 

55 degrees Celsius is the maximum temperature for liquids stored in oil tanks manufactured by Harlequin.

Yes, there are several approved online resellers of Harlequin products. You can also locate your nearest stockist of Harlequin tanks when viewing a specific product. You can click the 'Buy Online' tab when viewing any product listing in order to be directed to a list of online suppliers of the specific product you are viewing, or you can visit our 'Buy Online' page and answer a couple of brief questions in order for us to determine your tank needs.

Yes, all Harlequin domestic oil tanks have an OFCERT license, meaning they have gone through rigorous testing processes by OFTEC in order to gain approval for use.