Hi Yvonne,
I think the barbecue gremlins must have been at work!. We had the same problem this weekend.Just to add a twist to John L's theory we tried 2 different Barbie's one on Saturday and one on Sunday with both the same results.Both barbie burners had been cleaned and the only factor we came up with was that we used the same butane gas bottle.
I believe that I read on the forum a while ago about contaminated gas bottles, could this be the problem?.
Look forward to any other theory's.
Regards,
Nidge