Can someone please help, I am new to RVing and experienced a loud rumbling noise when the heater started on a cool night. My unit has two Penguin low profile units on the roof. The rumbling noise was ...
When new, my AC was replaced twice in an effort to reduce that rumbling. The last one got it down to a tolerable level. I would go up top and make sure the fan is perfectly clean. Even just normal dust and dirt build up can make it rougher. If that doesn't help then try rotating the clamp for the fan (up top) 180 degrees and see if it changes any.