dougrainer wrote:
Very simple. The flame/heat round internal tube that runs from the flame in and around and out the exhaust has a blockage/partial blockage. THIS is the cause of flame back or blow out when door is closed. BAD DEALER. Period. You remove the burner and the upper exhaust cover and use a water hose to wash out and a spring type snake to clean out the blockage. The standard test BEFORE you do this is to run a Golf ball down that tube. If it does not come out you have a blockage. You CANNOT see this blockage. Doug
X2 I would have thought the hoards that always talk about mud dauber wasps would have sounded off on this one. Doug probably has see a few and has some idea what the blockage is made of but my guess was blow back and a mud dauber nest. Ran into this often in remote summer cabins in the Sierra.
