Aquarius wf440 is tripping rcd tried the element but reading 34ohms

The grill element has an internal short and needs replacing. Sometimes you can see it as a slight bulging of the element. This happens just before it blows a hole. It may also have been physically damaged when something was put in there after a few Sherries. :>D Sounds like your RCD is adequately sensitive.

Check for short to ground or for no resistance on heating element with DVM "Digital Meter" If meter is not available try this - With circuit breaker turned off disconnect wires to bottom heating element - put caps on wires or otherwise islotate the connections from any metal. Turn breaker back on and adjust temp on oven if RCD does not trip then the element is bad "Shorted" replace element. Element can be shorted to ground or shorted internally. Additional information at this link "https://www.6ya.com/philip_b05beb373d913f26"

The elements in ovens consist of an outer earthed metal tube and an inner resistive element that is insulated from the outer tube by what is effectively a compressed ceramic insulating powder. If the element is not used for a while, enough atmospheric moisture, (or from spills, etc), can penetrate the insulation to cause enough earth leakage to trip the RCD. If the RCD is tripping at the correct level, (They can get too sensitive - see this article here:
Diagnosing RCD earth leakage breaker nuisance trips), then the only long term solution is to replace the element, although they can sometimes be dried out by heating them.

Check for loose connections on or near the element. Heat form the element could be causing the connection to expand causing arching and tripping the MCB.

I had the same problem. found out that the RCD was faulty & needed replaced. now o.k.

I would agree with you. Everything you say here certainly points to a faulty heating element. The original is fitted with two factory fitted clips so you may need to go to your local garage and get two jubilee clips as they don't usually come with the new element.

We need wiring diagram for HB905 Siemens double oven, to start with it kept tripping, element ok. Now we have no heat coming from the main oven.

Hi.
Sounds like you have a short or an earth fault.
if it trips right away, try it with the motor disconnected, if it still trips then you will probably have to call an engineer..

I suspect not the oven element at fault. you only way forward is to actually test the resistance of the element to earth with a megga if you can beg the use of one. be cautious about the result as on occasion, elements are only faulty to earth when hot. another way to test if you are cdarefull, is to connect the element to mains independently of the oven and see if the rcd trips

the fan element would have blown. it is not uncommon for an element to trip an rcd when it blows. you are on the right track, if you replace the element all your problems should go away