the ecam action says in case of double failure of the 2 channels computer of the zone control computer (ZCC)to be lower than 10'000 feet before opening the ram air.
as for the temperature,it says the temperature is fixed in case of one failure and no indication if 2 channels fail.
I think the valves stay in the last position, I have no more info.
in a case of dual PACK failure(valve blocked, hot temperature increase), there must be a by pass in the pack system to let engine air to be mixed with the trim valves air and ram air.I have no indication concerning this.
more info would be appreciated before I pass to a next system.