cannon cambridge double oven mk2

🙁 any idea’s how i fix my cannon cambridge double oven cooker?

the lower oven on my cannon double oven does ignite when it is switched on but will not produce a sufficent flame to get any temperature. I am aware there is a safety device that causes an initial delay normally of about one min before the burner comes on full – but in this case the burner never comes on full as if the safety device is restricting it ??