Flue

An 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.

Gas fired AGAs are available with several flue options, offering considerable flexibility of siting. Since the availability of an outside wall or chimney and the need to conform to strict safety legislation, tends to dictate the final positioning of the AGA, you should consult with your Distributor, who will need to carry out a site survey.

Therefore the following notes are for general information only.

Three options of flue types are available for a gas fired AGA, Open (conventional) flue, Balanced flue and Powered flue, which operate as follows:

Open flued AGA
Requires vertical connection to either a masonry chimney lined with an appropriate flexible lining, or a metal, prefabricated, twin wall flue system may be used. In either case, the flue must be not less than 100mm (4inch) internal diameter and must extend up above the main roof, terminating with an appropriate cowl.

Bends in the flue must be kept to a minimum and must not be less than 135 degrees from the vertical ( e.g. allowing the flue to rise by at least 45 degrees)

Flue sharing with other appliances is not allowed.

For aesthetic reasons, black, vitreous enamel pipe may be used to connect between the AGA and the flue or chimney, but no bend should occur close than 600mm to the AGA outlet. Single skin pipe must not be used outside of the immediate kitchen area.

Permanent ventilation for a combustion air supply into the kitchen is recommended and in some cases may be essential, particularly if the room is well sealed, or there are other appliances fitted. Extractor fans and cooker hoods do not provide an air supply into the room as they are busy sucking air out! Normally an airbrick sized 6 x 9 inches will be sufficient.

Typical Open flued AGA Installation

A Balanced Flue AGA
A ‘Room Sealed’ appliance requiring to be sited immediately AGAinst an outside wall.

There are restrictions on where a balanced flue may be sited, best summarised as follows:-
Minimum wall thickness 228mm Maximum wall thickness 600mm

‘ A’ At least 300mm below an opening window. ‘E’ At least 300mm from vertical drain pipes etc.
‘ F’ At least 600mm from a corner of the wall (either an internal or external angle)
‘ G’ At least 300mm above ground level.
If in a car port( not permitted in garage) then, ‘D’ At least 600mm below car port roof, and
‘ J’ At least 1200mm from opening door or window in the car port.

A Powered Flue AGA
Offers considerable flexibility in siting the cooker, as it does not have to be sited AGAinst an outside wall or requires a chimney. It can even be installed in an ‘Island’ or ‘Peninsular’ setting.

It uses a small diameter pipe(approx. 50mm) as a flue system, powered by a small electric fan inside the AGA.

Bends may be fitted (up to a maximum of 6) and the route taken can include passing underneath work units, under the floor, above doorways etc.

If only 2 bends are used, then the flue pipe can extend up to 9 metres in length.

In some cases it may be possible to discharge the flue pipe into an existing chimney if it proves difficult to reach an outside wall.

The permitted terminal positions are similar to those of the balanced flue shown previously, but dimension "E" is 150mm and dimension "F" is 200mm.

An airbrick into the kitchen will be required,

Please check with your Distributor, who will be able to visit site and advise further.

Ventilation

Permanent ventilation for a combustion air supply into the kitchen is recommended and in some cases may be essential, particularly if the room is well sealed, or there are other appliances fitted. Extractor fans and cooker hoods do not provide an air supply into the room as they are busy sucking air out! Normally an airbrick sized 6 x 9 inches will be sufficient.

Balanced Flue cookers do not require an air-vent.

Plumbing

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

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

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.

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.

Hearth

When choosing a site for an AGA there are a number of factors to consider which will influence its positioning.

Flue/Chimney
May require the AGA to be close to an existing chimney or AGAinst an outside wall. See separate sheet 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)
3 Oven 477kg (9.4cwt)
4 Oven 584kg (10cwt)

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

The hearth must be non combustible for a thickness of at least12mm

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 & 3 oven 987 x 679m
4 oven 1487 x 679

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

Alternatively, there are several purpose made plinths available to suit the parent AGA, the hot cupboard (for the 4 oven AGA) and the gas and electric Modules. These raise the height by either 65mm or 85mm.

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

Clearances

In most case, work units can be brought right up to the sides of the AGA, without the risk of damage from heat. 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.

In a recess situation, if the adjacent right-hand wall protrudes forward beyond the front of the AGA, then an additional width clearance is required of 116mm on the right hand side, to allow the oven door to be opened sufficiently. This 116mm clearance is also required to the left hand side in the case of the 3 oven AGA, unless a module is being installed as well.

If the AGA is to be installed in a 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.

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

AGA Dimensions:
Maximum depth over handrail etc 756mm
Maximum width, 2 and 3 oven 987mm, 4 oven 1487mm (see note above)
Maximum height with insulating lids open 1330mm (see note above)

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.

Electrics

A 240 Volt, 3 amp electrical supply is required by the Powered Flue and Balanced flue models. This is best obtained from a high level, (i.e. at the AGA top plate height) 13 amp socket, situated to the right of the AGA.

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.

Fuel

The gas supply pipe will normally be of 15mm diameter copper tube and be brought along to the front, lower corner of the left or right hand, side panels. In some cases it is also possible to bring the gas supply directly into the AGA through the base.

With the 3 oven model, there is provision for bringing the gas supply through the left hand side panel towards the rear.