2nd A/C Question

[PackerFan]

Been thinking about adding a 2nd A/C to our Montana 3100RL. The Montana is pre-wired for it and the Thermostat is set up for 2 Zones. Thinking of getting the Low-Profile Penguin 13,500 BTU unit.

Is there anything I should do or know before purchasing and adding it. Going to do the install myself.

Thanks ahead of time, Scott

[bncinwv]

You may want to double check that the ac prep includes the thermostat control wiring. It usually does not unless Montana-Keystone has changed this in the last couple of years. The thermostat will support the second zone if the thermostat control wire is there. On our factory installed second ac, it was also equipped with an additional sensor for temperature for the second zone. This also need to be in place. If you don't have these installed and don't want to fish wires, then the second ac needs to have the controls on it.
Bingo

[cdaniels]

quote:Originally posted by cdaniels

If you have the newer 6 button thermostats you are good to go. If u have the 5 button then the mother board in the new air has to be changed at that's where it gets complicated. Check your thermostats any ? Pm me. We had ours installed last year and ran into problems because we had the older 5 button thermostats. Now it's in we love it.

[CORattler]

Can't help, sorry. We currently only have one but I have my eye on the one you propose to get. I'd be interested to read posts about your choice and installation. Best of luck to you!

[jimcol]

I installed the second A/C myself and it is pretty easy. Worse part is getting it onto the roof. I went with the 15K btu on advice from Mudchief. His logic being if one goes out a 15k is going to do you more good than the 13.5k. The low profile wasn't important to me as the new unit was only 2"'s higher than the vent cover I removed. Did not duct mine or hook to the thermostat. Just use it in dump mode using the controls on the face of the unit. Works good for us! Jim

[PackerFan]

Check my thermostat and it is a Dometic and has 11 buttons on it. Not sure what the 5 or 6 button one looks like. Our Montana is a 2012. We also have the separate sensor in the bedroom ceiling.

[DQDick]

Sounds like you're good to go. Both of ours are full sized units, but that's because we spend most of our time in Kansas and Arizona and frequently both are running at the same time and need to be.

[Captain Joe]

You may want to install the optional heat strip also. Check to see if the A/C and stat will accept one. Mine did and it works great. Had both of my A/Cs installed with one. Will keep the RV warm down when the outside temps are as low as 48.
Good luck

[rapidrobert]

Would go with the 15,000. Doesn't cost much more.

[1retired06]

Installed matching unit in the front of ours. Hardest part was getting it on the roof, and being careful not to cut the roof membrane.

[cdaniels]

We went with the 15000 btu per Ozz suggestion as said not much different in price. This allows us to run the bedroom air during day and get rid of the noise when the temps are under 90. Over 90 we run both airs and it keeps it really cool. If you have the enclosed bath it's not as open as other units and not having it ducted the cool air tends to stay in the bedroom making it an ice box from what we where told when we where putting ours in last year. Ours is ducted and works great. When you order it make sure your thermostat is compatible with the model air you order. Since your unit is new and you have the newer thermostat there should be no problem.

[richfaa]

two A/C are handy. We had two in our 06 a 13.5 in the front. Both were noisy and we ran the front when we wanted to watch the TV in the rear .On this 13 3402 there is also two both 15.5 ducted units and they are very quiet. we actually have little use for using two of them at the same time due to our mode of travel but..they are handy.

[Denfinger]

We added the second air 13.5 and have been very happy with it. We did not choose the low profile as the 2 inches did not make that much of a difference to us. You DO have to make sure the Attic is sealed around the old fan opening using AC Thermal Tape, (Keystone used cut pieces of 1/4 " wood around our primary to seal it) Or the foil covered card board material(duct work) you can get at Home depot and cut to fit. Sealing the attic is critical to not sucking in the gasses from the tank vents on the roof. It does mention this lightly in the instructions, but I would tell you that you want to make sure you over achieve in the sealing of the attic. Other than that, you are good to go. Nice meeting you and your wife the other day at the KOA. Good luck.

[bw2]

When ordering the AC make sure to order the appropriate inside cowling/duct connections and the control unit for your use.

[Art-n-Marge]

Don't forget to find shore power of 50 amps. 30 amps will not run two A/Cs. Many campgrounds are still predominantly 30 amp, with some 50 amp limited to certain areas of the campground, so make it a top priority when checking in or reserving when inquiring about the availability of hookups.

I met someone who had the adapter to convert the physical 50 amp connector to a 30 amp connector to plug into shore power and didn't understand why he couldn't run both A/Cs. I did explain that besides the connector, the ratings are a separate consideration. Only a 50 amp connector AND a 50 amp power source will get you what you need. Just because you can convert the physical connector, doesn't mean the power rating goes with it. He ended up leaving the campground since it was 30amp only. But he did learn something. None of us are too old to learn something, happens to me all the time.

Back to the subject. My old 2006 rig is prewired for a 2nd A/C but only the 110 wire. There is no control wire or an easy way to tap into the existing ducting. I would get a discrete A/C with its own controls. I do agree that getting a 15K unit is better for those extra hot days, or if the other unit goes out it's better to have more than less for just a few dollars more.

[psomers]

I helped my son replace AC on top of his motor home a couple of years ago. He has a shed to keep his rv. We pulled rv out, put pulley at peak of rafter and pulled AC up then pulled rv back under ac. Let new ac down, pull old ac up and you get my drift. No big deal. No shed? Find big tree.

[Art-n-Marge]

I wasn't aware these A/C units weighed very much. My plan would be to lash the unit to a backpack frame, then carry it up the RV ladder. I don't weigh much and being a former backpacker we should be able to meet the weight limit of the ladder. I'm used to carrying 40-70 lbs on my back and legs over some steep miles with this load, so I hope this short of a jaunt up a ladder wouldn't be so bad. Or I could use my extension ladder (with a 300 lb load limit) if the RV ladder can't handle our weight.

But for those with winches and pulleys, have at it. Good job psomers, but I don't have a big enough tree close by. At least I won't have an old unit to bring down.

[WaltandLynne]

Be sure the thermostat and the new AC unit are compatible. We just added the second Penguin AC this spring and needed a conversion kit to make the older thermostat work.

Walt

[jimcol]

I pulled the truck up next to the 5th wheel with the slide out. Placed a 6 foot step ladder in the bed of the truck along with the new A/C still in the box. Picked up the A/C and placed it on the top of the ladder. Son in law balanced it on top of the ladder. I exited the bed of the truck got on the roof of the 5'er slide and guided the box as he boosted it. Once on the roof of the slide it was easy to get it to the main roof. Seems like the box weight was 90#'s. Not that big a deal for 2 people to get the unit on the roof. Jim

[PackerFan]

Thanks for all of the info everyone. One of the RV Tech's from work (I work at Camping World) is going to help me install it. He has installed many of this units. Just wanted to make sure I wasn't missing anything when getting all of the parts ordered.

Couple more questions to those who have done this....
1) Will the new unit be ducted into the existing ducts or is that an optional thing? I would like to have it ducted into the system.

2) If both units are venting into the same ducts doesn't that overload the system and fight each other?