How to Service an old AGA cooking range

Turn off the oil supply at the regulator (it's the lever on the right hand side and it needs to be lifted for 'off'). For the purposes of clarity, I have marked it with an orange spot.

This is a very heavy piece of kit, demanding a long pull to lift it out. This can be back-breaking. Be careful to protect the enamel top of the cooker, because when this thing's out, you won't be setting it down gently!

Because of its massive density, it holds the heat well, for even cooking temperatures.

That's right, we weighed the monster at 55 kgs. It was resting on 2 kgs of magazines, to protect the scales, hence the higher reading on the dial.

This is the oil vaporiser, complete with wicks. The 'chimney' parts have been removed from above, the oil feed disconnected and the burner pulled out through the front 'door'. The plug of carbon visible in the centre of the 'well' has virtually cut off the oil supply.

The central well can now be clearly seen, with the aperture through which oil wells up into the reservoir. The wicks are replaced every second or third service, depending upon their condition on inspection.

This is simply unscrewed, cleaned through and replaced, ensuring no oil leaks.

The view shows the clean chamber beneath the right hand plate, through which the exhaust gases travel en route to the main chimney

It is vital that the burner sits truly level, for efficacy and safety reasons. The assembled chimneys can now clearly be seen.

The regulator must be adjusted to ensure the correct level of oil in the burner well, to prevent accidental overflow (which would be a serious fire risk). If the oil fails to come through, despite the regulator being set at the correct height, there is probably an airlock. These can be stubborn to release an d I have, on occasions, had to apply a hose to the burner well opening and suck, to bring the oil through. If you watch the burner well as the oil comes through, it acts as a double check on the levelness of the burner.

Here the white rope seal can be seen, carefully positioned so that the lip of the heavy cylinder will rest on it and prevent the products of combustion from entering the kitchen, causing bad smells and toxic fumes. We replace the rope seal every second or third service.

This view is taken after replacement of the heavy cylinder.

There should be an incandescent red-purple upper region and a blue lower region, when the flame is burning correctly. Any flickering, yellow flame, smell or popping noises indicate a problem with the burn quality.

When 60 year-old cookers work this well, it is a testament to good manufacture.