Opinions/advice on installing Second AC unit

mfrey3

Member
So far this summer, my single ac has had a hard time keeping the 5er cool.
The unit is prepped for the second ac unit, but was wondering how hard it is to install. I am mainly curious about tying it into the existing ductwork and thermostat.

Any opinions or advise?
 

jimtoo

Moderator
Re: Second ac unit

Hi mfrey3,

Welcome to the Heartland Owners Forum and Family. We have a great bunch of people here with lots of information and all willing to share their knowledge if needed.

The hardest part is getting the A/C to the roof I have been told. The 2nd A/C will not tie into the duct work and thermostat. It will be totally separate unit, some will have a thermostat depending on the one you buy.

Enjoy the forum.

Jim M
 

newbie

Northern Virginia
Re: Second ac unit

I installed a 13,5 Carrier low profile AirV. I am not sure what you level of handiness is and that has a lot do do with how easy it is for you.

Like Jim said, getting it on the roof is a trick. I learned a great method on this forum and it worked really good for me. I leaned an extension ladder against the 5th wheel. I then tied a rope to the unopened box and double secured the rope with some Gorilla tape. I then simply pulled the box up the ladder while my wife held the ladder base (yes, she was nervous. She kept saying, "You love me honey, right?).

For me, the hardest (read time consuming) part was removing the old caulking from under the old vent. I used laquer thinner, rags and a puddy knife (very, carefully). It still took a couple of hours to remove the sealant (it is really, really sticky). After that, because it was pre-wired, it was simply a matter of following the instructions.

Our Landmark's roof was thicker than the bolts that came with the unit allowed for. I went to Lowes and substituted 5/16 all thread (threaded rod). The rod threads into tapped holes in the roof unit. I also need 5/16 nuts and washers against the interior mounting plate. Worked very well.

My unit didn't require a thermostat as it was built into the unit. Our Landmark did have a thermostat pre-wire in the ceiling. I have read that the other end is next to the bedroom light switch.

I spent a Saturday on this project and after several trips in 100* plus heat, I am glad I did. Now my wife complains that it's too cold in the bedroom. Also, two a/c's makes you 50 amp dependent.

John
 

Ray LeTourneau

Senior Member - Past Moderator
Re: Second ac unit

Before you go and spend money an a 2nd a/c unit read the attached thread. Right Here It's a very long thread but it's main point is a way to seriously improve the efficiency of your wxisting unit. I've also attached a pdf that was out together with a detailed set of instructions. It takes a couple 2 or 3 hours to do and well worth the time.
 

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newbie

Northern Virginia
Re: Second ac unit

No offense to anyone on the 'tent in a vent' bandwagon meant here. But, I eagerly tried and was disappointed in the results. I think part of my problem is my Styrofoam duct that goes to the bedroom is squashed. I don't think enough CFM's can get through the duct regardless of how many the fan is pushing in that direction. The second a/c was the solution for us.

John
 

leftyf

SSG Stumpy-VA Terrorist
Re: Second ac unit

So far this summer, my single ac has had a hard time keeping the 5er cool.
Any opinions or advise?


Rather than hassle with the ducting, I opted for the second unit. Sitting in the middle of this Virginia rice field I don't have a shade tree in 500 feet.

The single unit has never done it for me. Not in an Airstream...Not in the 3055. There are people that will tell you that with 110 degree outside temps, the 8K factory unit does it for them. But the 15.? + the 13.5K REALLY works for me.

Besides, the 65 degree inside temps allow me to snuggle with my PitBull

Bite the bullet, spring the $$$ and put the unit in. I'd rather have too much cooling than wishing I had more.
 

newbie

Northern Virginia
Re: Second ac unit

Rather than hassle with the ducting, I opted for the second unit. Sitting in the middle of this Virginia rice field I don't have a shade tree in 500 feet.

The single unit has never done it for me. Not in an Airstream...Not in the 3055. There are people that will tell you that with 110 degree outside temps, the 8K factory unit does it for them. But the 15.? + the 13.5K REALLY works for me.

Besides, the 65 degree inside temps allow me to snuggle with my PitBull

Bite the bullet, spring the $$$ and put the unit in. I'd rather have too much cooling than wishing I had more.

I couldn't agree more

John
 

hoefler

Well-known member
Re: Second ac unit

I installed a 2nd A/C in the bedroom of our Landmark last fall. Thinking I would only really need it when stopping after being on the road all day in the summer, then shut it off and let the ducted 15k take over once the temp was down to where it is comfortable. Last weekend in Tunica, Ms., our 15k was doing ok until the outside temp hit 105*. The temp in our rig was at 88* ( thermostat set at 73* ) and rising with the A/C running continuously. With all the black asphalt around us, it was stinking hot!!! I turned on the 2nd unit, it stablized at 91* for awhile and began to cool down after the sun started setting. The next day I left the 2nd A/C on and set at 75*. When we came back that day, the temp had hit 101* that day, but the rig was a comfortable 72* and both units cycling. Well worth the cost and effort!!
 

mfrey3

Member
Re: Second ac unit

Thanks for the replies everyone. Adding the second unit will be on the top of my next spring camping list.
 

jcarnevale

Well-known member
Re: Second ac unit

For those of you who like pictures. An inside look at the roof duct-work. I have more pic's if anyone needs them.

Jay

072.jpg
 

Ray LeTourneau

Senior Member - Past Moderator
Re: Second ac unit

Interesting picture! I'm guessing you were on a tour at the time. It appears the duct has built in diverters to direct air forward and aft. Was this your rig? If not, do you know what it is? Just curious because it doesn't appear to be a laminated roof.
 

jcarnevale

Well-known member
Re: Second ac unit

Interesting picture! I'm guessing you were on a tour at the time. It appears the duct has built in diverters to direct air forward and aft. Was this your rig? If not, do you know what it is? Just curious because it doesn't appear to be a laminated roof.

Yes, this is my roof at the factory just prior to being installed. It's a 3300RLB roof. Here's a closer look.
074.jpg

This roof is laying on a large assembly table, that's why the hole where the AC goes appears to be blocked.

Jay
 

nemo45

Well-known member
Re: Second ac unit

Besides all the other reasons listed here for adding the second A/C, we had our main A/C blower go out and have been without it for a month waiting for a new one from Dometic. They finally decided they couldn't get just the blower and are replacing the top half of the A/C. Anyway its sure been great having that second A/C for cooling the whole camper. We just use a big fan to blow the cool air to the rest of the camper. I set the thermostat at 64 deg. on the second A/C during the day and it keeps the rest of the camper about 10 deg. cooler than outside. Good thing we're in central WI. You could hang meat in the bedroom though. The repairman is coming Monday to install the new top half of the A/C. Thank God! The A/C in the bedroom is pretty noisy at night.
 

porthole

Retired
Re: Second ac unit

I haven't done the "tent in the vent" mod yet and am not sure if I will. On the really hot days (like the past 2 weeks) it was nice to be able to use the main AC dumping into the main area and the bedroom AC doing it's thing up front. Once cooled off at night I switched the BR AC off and switched the main unit to "ducted" This worked well and as long as there are some trees for shade we were able get by with just the main unit once the trailer had cooled down.

A big plus on this trip was finally running the generator while traveling with the AC on, that really helped.
 

davebennington

Senior Member
Re: Second ac unit

We are thinking about installing a second ac unit. Can someone tell me did you block the vents in the bedroom or just leave them open.

Dave
 

hoefler

Well-known member
Re: Second ac unit

Just left them open. Ours in the bedroom is a little loud, and at night you most likley won't need it anyways.
 

andy

Member
Re: Second ac unit

These vents with an without a shutoff like the bathroom one are now in the new parts cataloges at your camper dealer . I just keep mine shut off but if i was to have a a/c problem they would be there
 

newbie

Northern Virginia
Re: Second ac unit

Just left them open. Ours in the bedroom is a little loud, and at night you most likley won't need it anyways.
I have to have mine running at night. I love the white noise effect and have a hard time sleeping if it's not running. Maybe I just march to the beat of a different drummer...

John
 

porthole

Retired
Re: Second ac unit

Dave, don't block the bedroom vent. Like I posted above, when really hot we use both and have the main unit dump into the LR. At night we shut off the BR and open up the ducts, much quieter.
 

jbeletti

Well-known member
Re: Second ac unit

Dave, don't block the bedroom vent. Like I posted above, when really hot we use both and have the main unit dump into the LR. At night we shut off the BR and open up the ducts, much quieter.

We do the exact same as Duane.
 
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