Got an odd issue with my Duet gas dryer. Clothes have been taking a while to dry and did not seem all that warm coming out of the dryer. Opened up the front panel and observed the burner. When heat is called for it clicks, about 10 -15 seconds later another click and the igniter comes on. Gas vale opens and burns nice blue flame - for 20 seconds then cuts out. Repeats over and over with a time out between cycles. No vent blockage because it's not vented.