Hi and thank you for using Just Answer.
This sounds like a heat related issue. There is a heat limiter-switch that is built in which prevents your oven from over heating. For some reason you are not getting a draft pull and the heat is building up and then your heat limiter-switch will kick out shutting down the entire oven. When you open the door, then you created a way for a draft to come in and dissipate the heat. The draft problem is in the stove/oven it's self. There could be some packing or other blockage keeping the heat retained. The best way for you to confirm this is to get a thermometer (digital wire lead) and compare heat temps. Place the end of the thermostat into the oven mid way and bend it so it sits out partway in the middle. You want to create an "L" shape. With the reader set it off to the side so you can read it. Turn on the oven and set it to your "normal" using temperature with the door open first. Watch the temp and see where it rises to. When it plains out ... write it down and then close the door ... now watch. See if the temperature climbs. Let it go until the heat limiter kicks out/stove quits. If you get a drastic change in temperature then you have a draft problem. The heat isn't escaping like it should. Let me know how you do, and if you have questions, please ask. I wish you the best.
I saw that I didn't tell you that I want you to place the thermometer through the control gear door and get your reading from there.
Hi GaryThanks for responding to my query however, whilst I agree that the problem could now be a drafting problem within the oven, I could do with a diagram or exploded view of a 2 oven aga to see where it could be blocked.Thanks RegardsRobin
Hi Robin, In order for me to get you what you need, I need the model number of your oven. Also, I'm going to move this to Q&A so we can have more time to work on your problem. Thanks