Only 4 AC ducts in 36' TT

our outback came with 4 ducts also. It is adequate.

That said, a 13.5K BTU AC unit in the typical 35' trailer is getting pretty marginal when your in direct sun and high temps.

However, being the adventuresome type, I found it is very easy to add more vents to the existing ductwork. I added one in the bathroom into the duct that feeds the bedroom, one more in the bedroom (now 2 in the bedroom) and two more in the living area, one in each main duct. very easy to do and use the aireport (sp?) ducts that can easily be closed off and spread the air horizontally rather than straight down. That plus carefully sealing the ducts with aluminum duct tape to keep any cool air from going into the "attic" was worthwhile. Now it cools down quicker, and it is easy to quickly cool either the living area or BR by closing off vents.

LarryJM wrote:

Chris Bryant wrote:
My house only has a single outlet in each room, and 4 is the minimum required. As long as the back pressure is within limits, it should be fine.

That 4 is the min that is "PER RUN" and many systems have two runs (i.e. Ducts) so that would be 8 min Page 9 BriskAir ducted system. So your answer IMO lacks a lot of required information and is not applicable in every instance.

Mea culpa- you are correct. I blame 97 degrees in my shop for making a mistake on something that should be drilled in to my brain.

we found if were in front then close front vents,same thing for bedroom cools w/o blowing on us ken

OP- there is no problem.

Enjoy your trailer.

bigcitypopo wrote:
i bet there is a diverter on the main unit inside the RV. mine has a slide that i can direct air into the main cabin AND the returns...

I open it a little and then divert the rest to the bedrooms... helps a ton. AND the key to AC functioning properly is to have air moving in the room. I always have 3 small oscillating fans. in each room and the main cabin. This keeps the thermostat reading a true air temp rather than the duct blowing near the T-stat and shutting off.

I was in 120 degree heat... ya i know.. HOT and with the fans running, I kept the trailer to 85. not bad... seeing i have a 13.5k AC

The diverter you are talking about is not on all systems and is basically the "quick cool", etc. that has the ability to take air directly from the main air plenum and direct that into the RV. This is like a non ducted A/C and the extra registers I talked about in my prior post at the junction of the duct run and the main air plenum is a close substitute to what you are describing w/o hacking into the main air plenum or the inside A/C cover.

When I installed these "extra two registers" that helped the cooling in the main living area of the trailer by orders of magnitude (subjective description)

Larry

goducks10 wrote:
Too many and you lose pressure. Same as the furnace close some off and the air flow out the remaining is greater.

I disagree with your idea about pressure and closing off registers as you advocate is NOT the proper way to go ... see my prior post for some info. BTW for the link I gave 12 is the max number of registers for a dual run Briskair system.

Larry

Chris Bryant wrote:
My house only has a single outlet in each room, and 4 is the minimum required. As long as the back pressure is within limits, it should be fine.

That 4 is the min that is "PER RUN" and many systems have two runs (i.e. Ducts) so that would be 8 min Page 9 BriskAir ducted system. So your answer IMO lacks a lot of required information and is not applicable in every instance. Your note on back pressure is IMO valid, but most here can't measure that accurately so they have to rely on the number of registers and their size. There are also min free air register flow specs and I believe most A/C systems are at or even below the actual specs and the ever popular concept of closing off registers to redirect the A/C where needed actually reduces the overall cooling. IMO the best way like I have done is to install a couple of registers at the junction of each duct run and the main air plenum and add extra registers above the minimums so some register can be closed off. I now have 12 in my TT with 4 in the bedroom and two at the above mentioned junction so in hot weather I close the registers in the bedroom and close the curtain and my single 13.5 unit does a fine job cooling the rest of the trailer.

If you have a sandwiched type roof adding registers might be extremely easy since a lot of the ducts are cut into the solid insulation and you just have to cut holes in the roof below the duct run and install extra registers.

Larry

i bet there is a diverter on the main unit inside the RV. mine has a slide that i can direct air into the main cabin AND the returns...

I open it a little and then divert the rest to the bedrooms... helps a ton. AND the key to AC functioning properly is to have air moving in the room. I always have 3 small oscillating fans. in each room and the main cabin. This keeps the thermostat reading a true air temp rather than the duct blowing near the T-stat and shutting off.

I was in 120 degree heat... ya i know.. HOT and with the fans running, I kept the trailer to 85. not bad... seeing i have a 13.5k AC

Too many and you lose pressure. Same as the furnace close some off and the air flow out the remaining is greater.

Dog Folks wrote:
Our 27 foot outback has a 13.5K A/C unit and 5 outlets.

It is really more than enough. We can get it so cold you could use it to hang meat.

That's what my trailer in my signature below has and it also gets quite cold and had no problem keeping up to some very hot and humid days this summer.