Flues

An Oil-fired AGA requires some form of flue or chimney, so as to safely remove the natural products of combustion, at the same time taking cooking smells and steam from the ovens.

For the AGA to work properly, the chimney must be constructed of the the appropriate materials and rise to a satisfactory height, whilst complying with current legislation, such as the Building Regulations.

The need for access to a chimney will probably dictate the position chosen for the AGA, and we would strongly advise that your local AGA Distributor be asked to carry out a survey of the proposed site.

Two main chimney arrangements are available (see illustration below):

• To use a masonry chimney, suitably lined with an appropriate material and terminating at a height above the main roof ridge. An original, rigid lining would be of at least 150 mm diameter, but if a stainless steel flexible lining is used, this may be 125mm diameter.
• Where no convenient chimney exists, it is possible to use a twin walled, factory insulated, prefabricated, stainless steel chimney system, such as ‘S.M K’ from Selkirk or ‘ K Vent’ from RiteVent. AGAin, the internal diameter should be at least 127mm.

• No flue sharing with other appliances
• Bends to be kept to a minimum and must not be less than 135 degrees from the vertical.
• For aesthetic reasons, black vitreous enamelled, single skin, cast iron pipe may be used to connect between the AGA and the main chimney. The pipe will be 100mm diameter, rising vertically from the top of the AGA, before bending at 45 degrees into the chimney, where necessary. Single skin pipe must not extend outside of the kitchen area.
• Alternatively, it is sometimes possible to use a rear connection from the AGA, horizontally through the rear wall and into a chimney situated immediately behind. The horizontal pipe must be no longer than 150mm, I.e. the thickness of a single brick.
• The flue or chimney must terminate above the main roof ridge.
• In most cases a simple rain-cap should be sufficient as a terminal, but occasionally a venturi type cowl may be helpful, to overcome the effects of intermittent down draught, caused by the proximity of trees or other topographical features. Consider using the ‘Vedette’ or ‘O-H’ cowls. Electrically powered fanned flues are not recommended, due to the possible ill-effects in a power cut situation.
• The AGA oil burner requires a low, but consistent negative draught to function correctly. High up-draughts, experienced in windy or tall chimney locations, can adversely affect performance. Where this is likely to occur, we recommend an automatic ‘Draught Stabiliser’, to maintain the draught at the appropriate level. This is fitted in the flue pipe, adjacent to, and in the same room as the AGA.

Ventilation

Like all oil fired appliances, the AGA requires a permanent air supply into the kitchen to provide both air for combustion and also to enable the chimney to operate. A permanent opening of 29 sq.cm ( 4.5 sq.inch) free area is required and normally a 6" x 9" brick will provide this amount. Extractor fans and stove hoods do not give a supply of air into the room, as they are busy sucking it out, as do other appliances such as a tumble dryer. If other combustion appliances are fitted in the same room as the AGA, then additional ventilation will be required.

Plumbing

With most models of AGA, you have the option of obtaining domestic hot water.

This provides an economic way of producing either 410 litres (90 gallons) of hot water, spread out over a 24 hour period, regardless of how much cooking is carried out.

With the 2 oven oil fired AGA only, there is an optional larger boiler available, which will increase the domestic hot water output to 614 litres (135 gallons) over the same 24 hour period.

Hot water is generated within the AGA and circulates through a conventional, open vented, gravity system into a 190 litre storage cylinder, located within 5 metres of the AGA. With the larger 135 boiler, a correspondingly increased, 280 litre, storage cylinder is required.

Does the AGA produce domestic hot water for free?
There is a slight increase in the fuel consumption of a boiler model, but it is still an economic way of obtaining hot-water.

Will the hot water demands affect the AGA’s cooking performance?
No. The boiler draws its heat indirectly from the burner chamber/ fire-barrel.

What happens if we do not use all the hot water produced by the AGA?
There will be an increase in the temperature of the domestic hot water, but overheating is unlikely under normal circumstances.

What if we need more hot water than the AGA will produce?
There is no reason why an electric immersion heater cannot be fitted to the cylinder, for occasions when top-ups are required. Alternatively, it is sometimes possible to interconnect the AGA into a ‘shared system’ with another boiler or heat source. Special controls and plumbing arrangements will be required, and the AGA must be allowed to contribute the bulk of the heat required. A special ‘ twin coil’ cylinder is often used in such circumstances.

Can we fit a thermostat to the AGA to control the hot water temperature?
No. If there are concerns regarding the upper temperature limit, then consider fitting a mixing valve at the cylinder outlet.

Can the AGA be used to supply a radiator?
The AGA is designed to release just enough heat from its boiler to generate 90 gallons of hot water over 24 hours. Fitting even a small radiator would seriously reduce the amount of domestic hot water available.

What about a towel rail?
As above, fitting a towel rail will reduce the hot water production. In some households, this might be useful, if demands for hot water are limited, in which case, the towel rail will act as a heat-leak.

What happens in a hard water area?
The plumbing system for an AGA should be of the ‘indirect’ type, in which case lime-scale will not be a problem. Older AGA’s may have been connected to ‘direct’ systems and may require occasional de-scaling, if the boiler becomes noisy.

Can the AGA be connected to a ‘sealed’ hot water system?
An AGA must be connected to a vented system, with an appropriate feed and expansion tank. Some proprietary ‘Thermal Store’ cylinders may be connected to an AGA, such as the ‘Mainsflow’ from Albion cylinders. This allows the hot water to be at mains pressure. Further details of this type of system and the necessary controls required, should be obtained from the relevant cylinder manufacturer.

Can a boiler be fitted to an existing ‘dry’ AGA?
Recent AGA’s can usually have a boiler added fairly easily. Ask your AGA Distributor for more details or a quotation.

We no longer want hot water from our AGA. Can we just disconnect the boiler?
To make the AGA safe, the boiler will need to be removed and insulation material put in its place, to maintain efficiency. This work is fairly straightforward, please ask your AGA Distributor for further details.

The water supply to the house is to be off for a short while. What should we do?
The AGA may be left on, preferably with the thermostat turned down low. Do not draw any hot water out of the taps. If the water is likely to be off for more than a few hours the fire should be let out.

Flue/Chimney

May require the AGA to be close to an existing chimney or against an outside wall. See separate sheets on flues/chimney/ventilation.

Floor/Hearth/Plinth

The floor must be strong enough to carry the weight of the AGA, typically:

2 Oven 406kg (8cwt)
4 Oven 584kg (11.5cwt)

Where an AGA Electric or Gas Module is attached add 129kg (2.5cwt)

The hearth must be non combustible for a thickness of at least 12mm

A raised plinth is not essential, and there is no reason why an AGA shouldn’t sit on the normal floor ( providing it meets the above criteria).

If a higher working position is preferred, or the finished height needs to match adjacent work surfaces, then a cast concrete slab, usually 50mm thick, is the answer. The slab dimensions should be the same as the base of the AGA:

2 oven 987 x 679mm
4 oven 1487 x 679mm

The 679 dimension can be reduced slightly if the front of the plinth is to be tiled.

Alternatively, there are also three purpose made plinths available to suit either a 2 oven gas or oil fired AGA, the hot cupboard (for the 4 oven AGA) and another for the gas and electric Modules.

Whatever type of hearth is chosen, it must be absolutely level in all directions.

Clearances

An oil-fired AGA requires an oil control valve to be fitted on its left or right hand side. (Note. If an AGA module is also installed then the valve must be fitted to the R.H side) This valve requires easy access for adjustment and servicing, therefore if the AGA is to be installed in a recess, increased width clearances are needed, significantly larger than the actual AGA dimensions.

In this view the oil control valve is shown on the left hand side of a 2 oven stove. Total Clearance required = 1303mm. (i.e.AGA width 987 mm + oil valve access 200 mm + door opening clearance 116 mm).

If the right hand wall does not protrude forward beyond the front of the AGA, then there is no need for a clearance here. In this case the Total clearance required would be 1187mm. (i.e. AGA width 987mm + valve clearance 200mm).

Had the valve been installed on the right hand side, there would be no need for a gap on the left, therefore the Total Clearance required = 1187mm, whether or not the right hand wall extends forward.

For a 4 oven AGA, add 500mm to stove width in the above calculations.

If the AGA is to be installed in a tight brick recess, then the minimum clearances should be increased by at least 10mm on either side, to allow for the walls being out of square and also for the natural dimensional variations found in castings.

If the AGA is not going into a tight recess, but merely between kitchen work units, then there is no reason why the units cannot be brought up to the side of the AGA, with the Oil control valve being actually located in the cupboard, the latter having a false wall. Zero clearances are then required.

Under some special circumstances, it may be possible to site the oil control valve remotely from the AGA, but the distance from the burner must not exceed 3 metres.

Work tops should however stop short of the AGA top plate and not actually touch it. Any slight gap can be filled with a silicone sealant.

If the surrounding walls are to be tiled, then this must be done before the AGA is installed, as the tiles must be taken down below the AGA top plate level, not finish above it.

The rear wall must be non combustible for at least 25mm thickness.

At least 60mm clearance should be allowed above the insulating covers in their vertical, open position.

Electricity Supply

A 240 volt 3 amp supply is required to operate the thermostatic control. This is best provided by a 13 amp socket, located at low level, adjacent to the Oil control Valve.

If a 4 oven AGA is fitted with the gas or electric hob option in its hot cupboard, then an additional 13 amp electrical supply will be required at high level.

AGA Dimensions

Maximum depth over handrail etc 756mm
Maximum width, 2 oven 987mm, 4 oven 1487mm (see note above)
Maximum height with insulating lids open 1330mm (see note above)

Heat to Room

The AGA releases a gentle warmth into the kitchen, which is not likely to give rise to any problems, unless the room is exceptionally small or poorly ventilated. The actual output varies slightly from model to model and in accordance with the type of flue system chosen. An average contribution to the room of 1 kW/hr should be allowed.

Fuel Supply

Oil storage and supply line
There are a number of important points to consider regarding the fuel supply.

Storage tank
These may be constructed of steel or plastic, to the relevant standard. An ideal capacity is 1400 litres (300gallons). The tank must be sited in accordance with current regulations so as to minimise the risk of fire or fuel spillage.

The fuel must flow by gravity to the AGA, therefore the tank must be sited at a higher level than the stove, with the base of the oil tank not less than 450mm above the base of the AGA, but the top of the oil tank not higher than 3.2m above the base of the AGA. Only a bottom outlet tank must be used.

If the tank cannot be sited higher than the AGA, then as a last resort, a proprietary ‘Oil lifting’ device can be used, but this introduces essential dependence on electricity for the AGA operation. De-aeration devices, ‘Tiger Loops’ or 2 pipe systems cannot be used with an AGA.

Fuel Pipe
This should be of at least 10mm diameter, preferably of soft, plastic coated copper, suitably protected where underground. A steady fall from the tank to the AGA is desirable, to avoid air locks. Sharing the oil supply pipe with another oil appliance is not recommended.

Filter
A strainer/filter should be fitted at the oil tank, together with a contents gauge and service valve. An additional 5- 10 micron filter is fitted adjacent to the AGA.

Fire-valve
A fire valve must be fitted at the point where the fuel line enters the property, with its sensor inside the property, to isolate the fuel in the event of a property fire. A second fire-valve is fitted adjacent to the AGA, with its sensor located inside the burner housing, to detect any malfunction in that area. Both fire-valves should be rated at 66 deg.C

Fuel

• The oil fired AGA is designed to burn Commercial grade Kerosene, Class C2, suitable for vapourising burners.
• Fuel Additives are not required or recommended.
• GasOil (Diesel) is not suitable.
• See also Flues & Ventilation and Domestic Hot Water requirements
• IMPORTANT. All AGA products must be installed in accordance with current legislation. Please refer to the main Installation Instructions for this product, regarding further information.