Installing an Air Conditioner

I think it's actually P-UP as in Pop-UP but people just lose the hyphen
and call it a pup.

Now, that makes sense.

Frank

I'm starting a new thread on installing brakes.

I think it's actually P-UP as in Pop-UP but people just lose the hyphen and call it a pup.

OK on PU, but I have assumed (hate that word) that PUP stood for Pop Up P?

It's the last P that I don't understand

Frank

PU is usually reserved for a pick-up.

Well, the install is finished on my PUP (by the way, what does the last "P" stand for?)

My roof is actually a bit stronger than I thought as it is composed of top to bottom:
1. a 1/4" Fiberglass composite sheet
2. a 1/4" plywood? sheet (or composite board)
3. a 3/4" frame for the A/C
4. a 1/4" inside panel

Giving me a total depth of 1 1/4". Along the outside edges of the roof is a
3 1/2" wide by 3/4" thick support board, then inside that are two (2) 1/8"
steel braces running along the outside edge of the trailer roof and and
additional two (2) 1/8" steel braces running at aprox. 14" inside that for
roof strength. The frame for the A/C is also 3 1/2" wide with cross pieces at
each edge. There are also pieces at 28" intervals running crosswise on the
width of the trailer, the length of the trailer.
All of this is glued to each other for strength and support.
I don't think there is going to be too much flexing with this setup.
The A/C had a built in compression gasket built into the unit as well as
front and rear support pieces for keeping the motion fore and aft and side
to side under control. When you installed the mounting frame and bolts
there was compression tabs to indicate how far to draw the unit down to
form a seal with the roof. I had also bought the optional heat strip to
"take off the chill" in the mornings and after installing and mounting all
this it was time for installing the power to the unit. In my case wiremold
was the obvious way to go, so I installed it so that I could drill up into the
roof cavity and hit my previously gouged and drilled out channel. I ran the
flexible SJTO cord (gas & oil resistant) through the wire mold, (I had to strip
the outer covering and then tape wrap it in order to do this) into the A/C
cutout and wired up to the control unit. Plugged in the A/C and the Heat Strip,
mounted the Control and Air plenum on the ceiling and then applied power
to the trailer. By the way, my A/C was pre-wired to down below the cabinets
with 120 V AC to a junction box and on it's own circuit breaker in the AC
distribution panel.
Everything worked as advertised and the unit put out a nice stream of either
heated or air conditioned air into the Pop Up. The controls work perfectly, so
I broke everything down and put the trailer away for a few days.
The next project is the electric brakes for the trailer and wiring the tow
vehicle for the brakes.

Frank

My roof mount air conditioner installed by the dealer after my purchase also included two metal support pieces on the ceiling side of the roof on each side of the air conditioner to give the roof more support. Similar to these google photos of the POPUP interior ceiling. The fiberglass type roof of the STARCRAFT has a membrane on top, then an area of foam with the 1/4-inch ceiling panel on the bottom. There are small wood studs running across the roof between the roof membrane and the interior ceiling panel at various points. They beefed the sides of 14 x 14 - hole with wood supports.

My air conditioner is the RVP RV PRODUCTS 8333D Series MACH 3 PLUS 13,500 BTU model.





My 120VAC runs from the air conditioner unit like shown in the google photo but goes to the wall and down behind the valance curtain. Then routes to the rear of the roof and drops down along the zip up window flaps and plugs into a 20AMP 120VAC installed receptacle which is on its own 20AMP circuit breaker in the 120VAC Distribution Panel. I have to plug this cord in to use the air conditioner after the roof has been raised. This 13,500 BTU model added alot of weight to the roof and my electric motor creaks and makes noises as it goes up but has worked great since the 2008 install.

My 2KW Generator is too small to run this air conditioner so it only get used when we are plugged into a 30AMP shore power pedestal. Most of our camping is off the power grid so it doesn't get used all that much by us.

Roy Ken

Well, I have started the project.
First I Made slightly less than 14" marks on the ceiling (Inside)
and then cut out a 12" Square in the inside panel.

Problem #1:
The inside of the A/C Frame has a 3/4" foam piece of insulation inside. Glued on both the upper and lower sides. I had to scrape
and cut this out as best I could to find the edge of the A/C frame. The screw WAS NOT in the middle of the cutout.
Good thing that I was cautious.

Problem #2:
After scraping and gouging the foam away from the A/C frame I discovered that the access hole for the electric service was not
drilled.
I drilled an appropriate sized hole for the wire feed and found out
that the foam is also in the next section. All the way to the outer
wall. I did manage to get a fish tape to the outside wall by unscrewing and lowering the inside center 12 volt light fixture.
Then I passed the fish tape through the foam in and around the
light fixture to get to the outside wall.

Problem #3:
I could not get the fish tape to bend far enough to get a secure anchor to get the wire back through the ceiling so I attached a
thin pull rope to the fish tape and pulled it back to the A/C
opening. The rope broke!!! while pulling the wire into the ceiling.
Now the broken rope is in the space that I created by gouging the
foam with the fish tape.

So at this point, I drilled up through the roof line with a small drill to mark the corners from the outside. As it was getting on to
late evening and to dark to work much more, I called it a day,
closed up and covered the PUP and am now waiting for a most unusual rain in this part of the country to subside and then dry up.
Looks like my best bet is going to be to run the electric service in wiremold.

to be continued:

stop

That's smart, Frank... this one's an older Dometic DuoTherm installed by the original owner. We've plugged it in out in the driveway, and it seems to work alright, both heat & A/C, but it was probably not designed for pop-ups.

Anyway, as I mentioned in a DM to you, depending on how nasty the weather gets with this front coming through from the west, I hope to get to the project later this week. I'll take some close-up shots of the roof cross-section and other stuff as things progress and post them here... barring any unforeseen catastrophe, of course ;)

I wouldn't believe you wont get cracks and leaks as that heavy A/C unit bounces and flexes the roof continuously. I wouldn't even think about it. It can't be that hot at night

Maybe I should have mentioned that this A/C is the Coleman Mach 8 Low Profile
9,200 BTU Polar Cub and weighs 92 lbs.