i had a landlords certicate done on my flat. the gas guy capped of the cooker because he said the oven flame safety device was faulty. he said the flame should go to low rate then high rate then switch off the oven and the flame should go to low rate again. but mine went straight to high flame and thus he capped it off! is this right???how is that dangerous? he didnt ereally explain it to me to be honest. thank you