A/C sealing

[Thurman]

I read a post yesterday about sealing the area where the A/C mounts. I made a note as to the post location but can't find my note. My unit is a '15 Coachmen 310 BHDS. OKAnyway, I went out today, took the grill off of my A/C unit to inspect how the ducts are routed from the A/C unit and how they are sealed. There were two pieces of ducting, one on the driver's side which feeds three registers aft of the A/C unit and one on the curbside which feeds three registers forward of the A/C unit. They were not sealed. In the wooden framework for the A/C unit there were two rectangular cut outs for the duct material. The duct material was there but there was NO sealant of any type. I could place my finger, my fat finger, on each side and across the top of the ductwork. This allowed cold air to be blown into the rafters/attic of the camper. Between the metal plate the A/C hold down bolts go through and the bottom of the unit there was a good 1/2" gap. This allowed cold air to go right back to the return air side. There is an adjustable plate there but it was taped in the down position. I removed the mounting plate, removed a gob of wrinkled up foil tape and started over. I raised the plate that divides the inlet air from the cooled air, marked the proper height, and took it all back down. I used some really sticky foil tape to hold this divider in place and put it back together, no gap. I then closed the gaps all around the rectangular duct work and the wood framing with two layers of foil tape. After putting the grill back on I turned on the A/C unit. I'm serious people that there was much more air coming out of the open dump on the grill. I closed the grill dump to check the register and there was a noticeable increase in air flow. One other note in the thread I read was to check the duct work after the last registers on each end of the duct runs. I used an electrician's fish tape to find out if the ducts extended further than the registers. On each, front and back, the fish tape went a distance equal to the distance from each register to the front or back wall. Again, dumping cold air into the attic. I used pieces of cardboard to temporarily stop the air flow about two inches beyond each register, I have a particular foam product in mind and will get tomorrow. Again, with the ducting block off as it should be there was more air coming from the registers. This was a good two (2) hour project but well worth it.

[Bama Rambler]

You did very well finding and fixing the problem. It would have been great if you'd have taken before and after pictures. You know how we love pictures.

Thanks for taking the time to post this.

[Thurman]

I did take photos and only one of them is legible. I've tried to load it three time tonight. I'm calling a break for the night and will try tomorrow.

[Thurman]

IF this works there should be a photo showing the gaps around my ducted air duct work. These gaps were on both sides of the A/C unit. One side feeds the front of the TT, the other side feeds the rear of the TT. After sealing these gaps with some thin foam gasket material then foil tape there was a tremendous improvement in air flow from the A/C. I'm going to close off the ends of each duct run today and that should also help. More photos after that.