Jim and Wilma,
I am sorry but do not have the answer for you. I hope you hear from others on this. Sorry.
But I may be able to help other Landmark owners with floorplans other than the Grand Canyon.
Looking at the floorplans on the factory site, all Landmark floorplans except the Grand Canyon do not have the refer in a slide-out.
So for those floorplans, I was told by Holmes on Wheels that there are 2 fans above my refer. Those fans pull air in through outside vent on the wall behind the refer and pulls that air and refer heat up through the back of the case and out through that big refer vent on the roof.
I mention this to others because the 1 amp fuse in the 12 VDC circuit that powers my fans was blown and that is why at the rally, my refer would only get down to maybe 43 degrees. Also, for 2 fans, I am now using a 3 amp fuse. I learned to do this as a) my 1 amp fuse was blown and b) many owners of the Mobile Suites trailers had to switch to a 3 amp fuse as soon as they took delivery of their trailers. My fuse was the glass type and in a black plastic fuse holder behind the exterior refer vent on the slide.
Back to Jim and Wilma's issue with their refer that is in the slide-out - my understanding is that the venting is different as you cannot have a vent in the roof of the slide-out itself. I believe they are on the ends or end of the slide as well as on the outward facing wall.
Does anyone know if the Grand Canyon refer also has fans? Holmes did not mention it to me so i am unaware.
Jim