We often get phone calls from customers who have an oven that is not cooking food as well as it should do or it is smoking badly. After paying £70 upwards for an engineer to tell them in less than 10 minutes that there is nothing wrong with the oven, it just needs a good clean the customer contacts us.
Obviously this is a tough job for us, but nothing we cannot manage. Dirty ovens do not cook as well as clean ovens as the heat is unable to reflect off the enamel. Ovens can also smoke quite badly and set off fire alarms, quite often caused because the roof of the oven, above the element is thick with carbon.
When the oven heats up the carbon above the element is cooking too and hence the smoke. Sometimes it is best to call us before calling an engineer.