Technical Help RE Boilers

Technical help on oil-fired boilers in general and Hounsfield Boilers. And there is more information available under ‘‘Product Brochures and Videos‘. If you don’t install oil fired boilers on a regular basis, the Hounsfield Boilers team will be happy to provide additional technical advice. Call us on 01449 722461.

Bentone BF1 Burner used in Hounsfield Boilers
Bentone BF1 burner used in Hounsfield oil boilers

Bentone BF1 burner used in Hounsfield Boilers.

Bentone BF1 burner in service position

Bentone BF1 burner in service position

Benton is a subsiduary of Nu-Way Burners, a British Company established in 1948. The Bentone products are often more familiar than their brand: these include the B9, Sterling and Electro oil burners. These were sold under the EOGB brand and fitted to Danesmoor, Myson, Trianco and Potterton boilers.

Why the Bentone BF1 Burner?

Bentone’s BF1 is the only burner on the market designed from scratch for condensing oil boiler technology and complies with current NOx emission requirements.

The BF1 utilises industry standard components which means lower life-time costs for spare parts. These are around 30% lower than bespoke Riello burner components.

For the heating engineer, the BF1 is the easiest burner on the market to service. Removing the burner head provides access to all service components.

See our videos on the Bentone BF1 burner:

Unique Bentone BF1 Burner‘ – ‘How to Test the Bentone BF1 Burner‘ – ‘How to Service the Bentone BF1 Burner‘.
Or check out the many other Video Guides about Hounsfield Boilers.

Boiler Controls - Where are the Visible Neon Lights
Boiler Control Panel on Hounsfield oil Boilers

Boiler Control Panel with neon lights. Child proof, User friendly & Ultra safe.

Where is the control panel?

Every Hounsfield Boiler has neon indicators that are clearly visible through the front casing to communicate boiler status for mains power, burner lockout and high temperature lockout.

These are NOT ALWAYS FITTED ON OTHER BOILERS THESE DAYS but they are an essential aid for you and your engineer in our experience and are standard in all Tuscan boilers. They can also save you the cost of calling out an egineer to press a reset button.

See Thermostats for details on high temperate and frost thermostats.

Watch our helpful videos about the boiler controls:

How to install ‘Plug & Go’ Boiler Control Panel‘ – ‘How Visible Neon Lights help Homeowners and Heating Engineers
Or check out the many other Video Guides on Hounsfield Boilers.

Boiler Warranty - What does the warranty cover
Hounsfield Boiler warranty registration form, no quibble guarantee

Five year No Quibble Warranty

Our industry-leading warranty covers all components for five years, rather than just the heat exchanger, as you’ll find with many manufacturers. On the rare occasion of either a manufacturing or installation fault occurring, we have a “no quibble” policy.

For heat exchanger replacement after the warranty period, we have a discounted pricing structure based on age. The full price is only chargeable in year eleven.

We fit limit thermostats and set these at 90°C. The industry norm for limit thermostats is 110°C but we feel this temperature is too high and unsafe. Incidents of boiling water pouring through ceilings have occurred as a result. Our lower temperature for limit themostats also provides additional protection to the boiler and its components.


Building Regulations and Oil Boilers


Before replacing an old boiler, check the Building Regulations for Boilers. It is not always necessary to replace an old boiler with a condensing boiler.

Useful documents (click to view or download)

Non-condensing boiler exemption guide issue
Non-condensing boiler assessment form


Summary of Building Regulations Requirements

Reference: Guide to the Condensing Boiler Installation Assessment Procedure for Dwellings

Classification: “EASY” INSTALLATIONS

A condensing boiler should be installed where installation is “not difficult”. Typically, installations would be adjacent to external walls with low or high level horizontal flues.


The assessment procedure “is to be used in cases where it is expected to be impractical or too costly to install a condensing boiler”; the object of the assessment being to establish the lowest cost option. (ref. Guide section 1, Introduction, paragraph 3).

There are a number of ways to overcome these “difficult” installations; the objective of the assessment procedure is to allow for the extra costs of installing a condensing boiler and compare them with typical fuel savings over the lifetime of the boiler (ref. Guide section 2 last paragraph).

The assessment is based on a scoring system; if a total score of 1000 points or more is accrued either a condensing or non condensing boiler can be installed. Whatever the score, the boiler does not have to be fitted in the position shown on the assessment form, which will have been chosen for “least cost” without regard for householder preference. The householder can decide what’s best for them.

Condensate Drain Trap Options for Oil Boilers

Condensate drain traps size 22mm (code OBT1-CO) are provided with Tuscan condensing boilers. Depending on the site conditions other trap options may be more appropriate as shown in the diagram below. All of these trap fittings are normally available from a plumbers’ merchants.

Condensate Drain Trap Options for Tuscan Boilers

Condensate Drain Trap Options for Tuscan Boilers

Deaerators - Tigerloops - Are not required for Hounsfield Boilers

Why Hounsfield Boilers do not need a deaerator / Tigerloop


Tigerloops were introduced by Boulter Boilers Ltd. over 25 years ago primarily to remove the need for two pipe systems, ie a flow and a return fuel line to the oil tank. They also alleviated a technical issue with the fuel pump on Riello burners: the solenoid valve  will not open with air present in the pump, a deaerator resolves this by circulating fuel until air is removed.

Why a deaerator / Tigerloop is unnecessary

  1. The solenoid valve on the Danfoss pump we specify opens immediately, passing air trapped in the fuel pump through the nozzle.
  2. The pump has a design suction capacity of minus (-) 0.6 to minus (-) 0.8 bar. Minus 0.33 bar is equal to a 4 metre Head.
  3. ‘Physics dicates’ that air begins to seperate from kerosene when suction is greater than 0.33 bar, that’s equal to a 4 mtr. head / lift height.
  4. A ‘typical’ wall mounted boiler installation would be lifting oil just 1 – 1.5 mtrs. (1-1.5 mtrs. head). Taking into consideration point 3 above, ther’s little point installing a devise to remove air.
  5. From experience we know boilers will function sucessfully when installed at heights in excess of 4 mtrs.. Of course we wouldn’t recommend this from a service access perspective, but it proves a point.
  6. Tigerloop’s technical data shows fuel flow from 3 to 110 ltrs. per hr.. A start point of three litres is at the top end of domestic appliance fuel flow rates, so prehaps it is a component more suited for commercial boiler applications.

This is why deaerators are unnecessary. Manufacturers of them recommend replacement every ten years. Domestic customers would also incurr associated service and maintenance costs for a component they do not require.

Hounsfield Boilers only use materials and components that will provide many years of trouble-free servicing thereby keeping whole-life running costs to a minimum. We are the only boiler manufacturer to provide a life-long flexible oil line which is a testament to this objective.

Fire Valves for Oil Boilers
Fire valve for Hounsfield oil Boilers

Fire valve

A remote sensing fire valve must be installed with the boiler; these are available with a range of capillary lengths from 2 to 35 meters as shown below, available from Hounsfield Boilers.

Pre-Assembled Fire Valve

Fire valve pre-assembled to oil filter for Tuscan wall mounted oil-fired Boiler

Fire Valve pre-assembled for Wall mounted oil boiler by Hounsfield Boilers

When you Order a Fire Valve with your boiler – We’ll pre-assemble it to the boiler filter as shown in the photo below for wall-mounted boilers. More details in the Fire valve brochure.

See the Hounsfield Boilers Fire Valve Products in our online shop.


Fuel Supply - How to install a single pipe fuel supply system

Fuel supply

Domestic oil fired boiler fuel supply systems are are typically fuelled with kerosene, also known as 28 second heating oil. Commercial oil fired boilers are generally fuelled by gas oil, also known as 35 second oil.

Oil fired boiler fuel supply systems

The Tuscan Oil Boiler requires only a “single pipe” for fuel supply; hence a Tiger Loop de-aerator or two pipe system is unnecessary. Thus saving on installation costs and also future costs in maintaining a Tigerloop system. A single pipe supply system is inherently safe from an oil spill perspective as oil is not being pumped via a return pipe line, which could malfunction, to the tank or a Tigerloop.

Domestic oil tank location

Domestic oil tank location for installation
Domestic oil tank location for installation


The pump’s lift / suction capacity provides greater flexibility than most when considering the location of the oil tank, allowing it to be sited at the bottom of an incline or up to 100 metres from the boiler.

Non Return valve

For installations where the oil level in the tank may become lower than the burner, a non-return valve will be required.Important! In a suction oil supply system particular attention is required to prevent air being sucked into the fuel line. Keep the number of joints to a minimum; in particular those that are likely to be above minimum oil level and subject to negative pressure.

What is a Tigerloop?

Tigerloop pipe system
Tigerloop is needed in many oil fired boiler fuel supply systems

Tigerloop is the brand name of a de-aerator, it removes air from the oil supply. They are often used in conjunction with some domestic burners that are unsuitable for “suction lift” systems in these situations the de-aerator is acting as a mini fuel reservoir.

Why a Tuscan Boiler doesn’t need a de-aerator

Physics dictates that air begins to separate from oil “typically” when suction is greater than minus 0.33 bar (= 3.3 metre head). Below that suction / lift height there will be no “air separation” problems to deal with for a boiler installed at our maximum recommended height of 1.5 metres above the minimum oil level in the fuel tank.
The Danfoss pump we fit to the BF1 burner has a suction lift capacity of 0.6 – 0.8 bar.

Heat Exchanger Design

Heat exchanger design
Modern Heat Exchanger design

Modern efficient heat exchanger design

Traditionally designed boilers have a fire brick in the base with a steel plate or covers on the top.

Our design requires a more specialised manufacturing process, with water surrounding the combustion box, but produces a more efficient unit by maximising the heat transfer surface area.

Stress fractures caused by “hot spots” are avoided and improved water circulation reduces the potential for corrosion caused by debris accumulation in the stagnant areas at the bottom of the heat exchanger.

High quality welding is a key feature of a Hounsfield Boiler. State-of-the-art Fronius synergic pulsed arc welding equipment ensures consistent weld quality.

Watch our helpful videos about the Heat exchanger
Unique Heat Exchange Boiler Design‘ -‘How to Service the Heat Exchanger
Or check out the many other Video Guides about Hounsfield Boilers.


Oil Filters

Paper Element Filter in Hounsfield Boilers
Paper Element Oil Filter included with Tuscan Boilers

Most boilers used to be sold by the manufacturer, complete with a paper element oil filter, BUT that doesn’t happen these days.

THE EXCEPTION is new Tuscan boilers – these are all supplied with oil filters & the necessary parts for filtration. A 15 micron paper element filter is supplied to be installed adjacent to the boiler.

A paper element filter is essential, gauze filters commonly used do not
provide adequate filtration and will lead to expensive premature boiler failure.
In supplying a filter kit we’re “controlling” the quality of filter installed, saving
you money in the long term and also saving your installation engineer hassle
in sourcing these components.

NOTE: Ensure there is enough clearance between the tank and the concrete base to allow maintenance of the oil filter. We recommend additional filtration adjacent to the oil tank.


Watch our helpful video – ‘How to Fit the Oil Filter in Tuscan Boilers – Video Guide
Or check out the many other Video Guides about Hounsfield Boilers.

Oil Line Hose

Life long flexible oil line
Life-long flexible oil line hose cored with stainless steel braiding – supplied with Tuscan Boilers

The oil line hose and all required fittings are supplied with our boilers.  As a standard we supply an aircraft-grade flexible fuel oil line hose, this is a ‘lifetime’ component that will not degrade like oil lines made from rubber or thermoplastic!

Watch the video on ‘Flexible Oil Line Hose‘.
We’ve videos on many other aspects of our Oil Boilers – Videos about Hounsfield Boilers.

Industry standard hoses are date coded. Some are called ‘long-life’ but all are made of rubber or thermoplastic, which will degrade over time and require regular replacement. It is recommended that some are replaced annually.

Out-of-date hoses can fail, resulting damahe to your home and expensive insurance claims for you or your engineer. We think that’s unacceptable.

For peace of mind for you and your service engineer, we fit ‘life-long’ aircraft grade oil line hoses NOT ‘long-life’ hoses. Teflon™ cored with stainless steel braiding, they will not degrade or require regular replacement.

Teflon® hoses will outlast a rubber or thermoplastic hose, and are used in space shuttles, air craft landing gear and braking systems. A Teflon® core stainless braid flex hose is supplied with every Hounsfield Boiler.

More details on the Teflon® Life-long Flexible Oil Line supplied with Hounsfield Boilers. Or see the Technical update – Teflon hose.


Oil Tank Fuel Supply

Oil tank with a top outlet should be installed to supply the heating fuel to operate the oil boiler. If the oil tank has a non-return valve fitted to the oil line, this should be removed.

The oil tank should be positioned with enough clearance between the tank and the concrete base holding the tank, to allow for future maintenance of the oil filter in the tank. Oil tanks should be inspected annually as part of your heating system’s regular service visit.

Watch the helpful video –How to Fit the Oil Fliter
Or check out the many other Video Guides about Hounsfield Boilers.

Note: Tank are required to comply with fire separation distances in order to adequately protect the stored fuel from a fire or heat source, more on domestic oil tank location.

Oil Tank Location for Fuel Supply to Tuscan Oil Boiler

Location for Domestic oil tank

Priming Oil Burner

Priming oil burner on Hounsfield boiler

  • Press the reset button, the firing sequence will commence.
  • During the firing sequence slacken the vent plug to purge air from the oil line.
  • If ignition fails the burner will go to lockout, wait for two minutes while the bimetallic strip in the control box cools and repeat the procedure.

Warning! Be careful, do not select the pump pressure adjustment screw.


High Temperature Thermostats

We fit adjustable limit thermostats, set at 90oC. The industry norm is to fit limit thermostats with a fixed setting of 110oC, we believe that’s unsafe, there have been incidents of boiling water pouring through ceilings as a result. It also provides additional protection to the boiler and its components.

Frost thermostat

External model boilers are fitted with a frost thermostat this senses water temperature, some boilers are fitted with cheaper air temperature versions, these will cause the boiler to fire unnecessarily and may cause disturbance for
the home owner in the middle of the night.

NOTE ON INTEGRAL PROGRAMMERS: We do not fit integral programmers; they’re not suited to the high residual temperature of an oil-fired boiler and will fail, there are far better solutions that will stand the test of time.

Other technical items are dealt with on the following pages:
Register Boiler WarrantyBrochures & Video GuidesFlue Options – Heating Systems Explained

If you would like to know more about the Hounsfield Boilers’ range, CALL 01449 722461 or use our contact form.