Our machine said Fault F13, and gave the Dyson service number to call. It was indeed the heater element. Now, our machine was over 5 years old, and I fully expected to pay the £85 callout charge which apparently includes any necessary parts to fix whatever the problem is - even down to a new drum or motor.
The whole thing was fixed for FREE. This is because this particular part had been upgraded since we bought the machine along with one or two other parts, and Dyson don't charge for upgrading a machine!
If the parts they replaced were already the upgraded bits, then they would have charged the £85. I can't completely work out the logic in this, but the service was FANTASTIC.
Don't be scared of calling that number. The most you will pay is £85, and it may not even cost you a bean.
John, January 2008