Installed 2d AC unit

[robhotdog]

Jim, I responded every way I know. I'm a professional repair and diagnostic tech. I'm assuming his model # has only 1 duct system in roof. 1 blower on each end. With 1 off, due to open vents, wouldn't it be normal to loose velocity as it vents out down the line? I don't have CFM data on the units. Unless he has a hole in his ducting, I believe WE have normal expectation of ops. Also common sense tells me the reason a front unit is installed is BECAUSE of weak flow from rear. The way I use mine in front only ops is, I cool down with both units. Max cooling with grille vents OPEN. Then when its reached I close and let system cycle. Typically late at night, kicked back I shut off rear unit to watch tv. Bed time, I shut off front and start the rear..I don't like being woke up when the bedroom unit comes on. My son likes WHITE noise so he leaves his on low fan and it cycles as needed. Also, These trailers arnt as well insulated as home. I would expect to use both units in the heat of the day.

[robhotdog]

One last thought, I'm not a grand design REP. I just modify-update and maintain my 29RS FW. I suggest contacting GD support. Ive had an issue with mine and it was resolved beyond my expectations! ( I was the second owner of a 2015) They are Great, and here for us!

[Cate&Rob]

An assumption in this discussion seems to be that the front AC has the same CFM capacity as the rear AC. It is likely a smaller unit and won't have the same ability to push air to the rear as the main unit has to push air to the front.

(another) Rob

[robhotdog]

yup.assumption. my low profile unit is same btu and 4 inches shorter..blows had as hell. to assume, you would need the standatd unit same as rear in front for an apples to apples test. but by feel it blows the same in the rear of mine. I can feel it sitting on the couch..bearly..the same as rear to front...wish i had californa weather here!😂

[ritterjd]

Just finished the front install on ours. UTUBE has 2 videos on a grand design front a/c install. I bought a penguin low profile and the same tstat that's on our main unit.
The video DOESNT give part #s! used on install. (too many design differences) I called dometic support. They fixed me up with the same as the install video. (control box already installed in unit) Also ordered cover for Ducted install. I studied how to get the 100lb unit on the roof..not trusting the SLIDE method, I borrowed 2 sections of scaffolding from a neighbor. Set up on left side. 2 step process and across to my son sitting on side. Also, THE MOST IMOPORTANT PART is sealing the partitions from inlet air to outlet air to the ductwork!! Some metal ducting tape, a plastic filler panel to seal and close all areas in roof. finished off with sealer. The front expanding foam worked great in the front void area. I had 1 hick-up...No Install bolts came with the unit! I needed 8 inch 1/4 20 bolts to secure the roof unit..thread stock and welded on nuts..AARRGGG!! The small unit works great! no issues at all!! Now I can turn the rear unit off for peace and almost quiet in livingroom!

Can you provide that part numbers that were needed? I have been researching this but find the choices confusing.

[robhotdog]

I used P/N 641915CXX1J0 Black low pro. a/c (control box built in) (campersparadise.com) 819.47 best price I could find..free shipping.
P/N 3313192.019 Black t-stat 31.95
P/N 3105935.047 Cover 69.95 Dyres RV parts on line. best prices on other 2. All dometic P/Ns

Hope this helps. Google the #s and make sure that's what you want. Matched My O.E. Perfectly!
Also, look for the long bolts in cover kit...mine was missing! Good luck! Did it under a grand! ( you owe me a beer) Rob

[robhotdog]

update..THANK GOD the front unit does a great job..The rear unit developed a problem at camp..coils clean and fans running..compressor is on and barely cooling..100 degree sun..noticed no condensation from rear. closed off ft vents. covered skylight..👌