Installing a second a/c unit

[DJ85]

Has anyone ever self installed a second A/C unit on their rv. My RES 327 came with the second a/c prewired already so all I have to do is buy a second unit and install it. Just trying to see if this is a big job and I should leave it to professionals? Or if it was a basic job that a semi-skilled person to do. From what I undeerstand it will fit in the standard vent roof opening and it's pretty much a bolt in and a simple wiring job. So if there is someone that has done one I am looking for some info on how it went.

[smiller]

It's really pretty easy, the biggest job is just figuring how to get the thing up onto the roof (definitely a two-person job there.). It's also a bit of a PITA cleaning up all the sealant left over when the manual vent is removed (so the air conditioner seals properly), but with some elbow grease it can be done. But otherwise if the unit is pre-prepped then it's as you say, just a bolt-in and wiring job. Follow the manufacturer's instructions and it should all be straightforward.

Also in my case I had to re-locate a ceiling light and A/C vent, but neither was that difficult. Keystone had placed both so close to the vent opening that there wasn't enough clearance for the the inside air director part of the A/C! You'd think leaving enough room might be part of the 'second A/C prep'..?

[Roberson4]

I agree with smiller.

I added a second AC/heat unit to our 5ver little over a month ago.

I was able to roll the ceiling vent sealant off with my fingers. Did get several blisters, but it was worth it. I did do a final cleaning with rubbing alcohol before setting the new AC/heater in place.

After the job was done I was glad I saved the money and installed it myself.

I draped a thick sleeping bag over the top/side of the roof. leaned a alum. ext. ladder there and tied a rope to the crate the AC was strapped to. I pulled the rope while my did pushed the AC up the ladder. It was fairly easy to get it on the roof this way.

[SAABDOCTOR]

DJ85 HI THERE GETTING THE UNIT UP IS THE FUN PART. BECAREFULL NOT TO DAMAGE THE OOF MEMBRAIN PUT AN OLD BEECH TOWL DOWN AND SET THE UNIT ON IT WHILEYOUR GETTING SET UP. TAKE YOUR TIME TO CLEAN THE SEALANT OFF AND WHEN YOU GET READT TO PUT THE A/C IN PLACE DON'T BE CHEAP WITH THE SEALER. I WOULD PUT IT IN PLACE DRY AND MAKE ALL THE CONECTIONS AND MAKE SURE IT WORKS WELL FIRST. THEN DO THE SEALER THING. ALSO WHEN I FIRST TOOK THE COVER OFF I WAS SHOCK AT THE SORRY ****TY WORKMANSHIP OF THE DOMETIC UNIT QUESS WHERE IT WAS MADE? THE FAN WAS BENT AND SOME OF THE PIPE SUPORTS WERE JUST HANGING UNSECURED. TOOK PICTURES OF EVERYTHING SENT IT OFF TO OMETIC AND THEY GAVE ME AN EXTENDED WARRANTY. HOPE YOURS IS BETTER. BUT IT IS NOT A BAD JOB LIKE SMILLER SAID ONE MAYBE TWO BEERS. IF IT GOES TO THREE BECARFUL GETTING OFF THE ROOF DON'T WANT TO HEAR YOUR IN THE HOSPITAL WITH A BROKEN LEG

[DJ85]

Okay it seems like I should be able to do this myself if I can get the unit onto the roof. Heres the next question? Dometic or the colmen unit. I was told that I already have a 13,500 dometic on the camper already. I also have been told that the Colmen is a cheaper unit cost wise that is. The only difference is the way they look on top of the camper I guess matching shouds. That really not important to me. I don't think it will hurt the resale value if they don't match. I don't want to spend money just to match units unless there is some other reason. I was also told that the colmen doesn't draw as many amps for start up. Power seems to always be a problem with these keystones. The camp grounds we go to are mostly only 30 amp sites. I was also told that on a 30 amp circuit you can only one which is not a problem the one in the bedroom will only run at night so I can turn the other one off. Lot of questions I know, but I would like to know possibly everything before I do this project. I don't want to do it if it's going to come out as useless.

[SAD]

Originally Posted by DJ85

Okay it seems like I should be able to do this myself if I can get the unit onto the roof. Heres the next question? Dometic or the colmen unit. I was told that I already have a 13,500 dometic on the camper already. I also have been told that the Colmen is a cheaper unit cost wise that is. The only difference is the way they look on top of the camper I guess matching shouds. That really not important to me. I don't think it will hurt the resale value if they don't match. I don't want to spend money just to match units unless there is some other reason. I was also told that the colmen doesn't draw as many amps for start up. Power seems to always be a problem with these keystones. The camp grounds we go to are mostly only 30 amp sites. I was also told that on a 30 amp circuit you can only one which is not a problem the one in the bedroom will only run at night so I can turn the other one off. Lot of questions I know, but I would like to know possibly everything before I do this project. I don't want to do it if it's going to come out as useless.

Back when I had a TH, we added a second A/C. As far as picking which one, we basically chose the model/brand based upon which one had the interior/shroud features we liked (i.e. vents you could close off, center dump, vent oscillations, etc)...

The though of exterior shroud match never crossed my mind. Neither did cost actually since they were all within like $150 of each other IIRC.

[JoeofNSB]

I installed a second unit in my Raptor and it was easy. Getting it up on the roof was the tricky part but I used a long extension ladder as a ramp, built a small wooden slide and used a long rope with the help of my children pulling. X2 on protecting the roof!!!!!! I did have to modify the existing a/c duct in the bedroom because it was partially in the way of the new face plate. Very happy with the result. I used a Carrier 5 unit for mine. has electric heat which is nice for those cool mornings (not in Florida) without having to use propane when the electric is included at sites.

Like the Craftsman tool commercial - "you can do it - seems a simple motivational speech was all that's necessary"

[smiller]

Originally Posted by DJ85

I was also told that on a 30 amp circuit you can only one which is not a problem the one in the bedroom will only run at night so I can turn the other one off.

I think you may find out that you prefer to run the main unit at night, not the bedroom unit as none of the typical RV A/C units are exactly whisper-quiet and having the unit five feet from your head (as is the case in many bedroom installations) doesn't help things at all.

What we normally do is run both units when outside temps are high during the day, then if A/C is needed at night we run the living room unit... keeps us cool and is much quieter in the bedroom.

[byrdr1]

Originally Posted by smiller

I think you may find out that you prefer to run the main unit at night, not the bedroom unit as none of the typical RV A/C units are exactly whisper-quiet and having the unit five feet from your head (as is the case in many bedroom installations) doesn't help things at all.

What we normally do is run both units when outside temps are high during the day, then if A/C is needed at night we run the living room unit... keeps us cool and is much quieter in the bedroom.

Thats what we did last year after I figured out it was too cold in the bedroom at night, once I figured out the tempature ranges it worked as needed. BUT It is loud just over your head. Your main unit is a 13.5Kbtu. Mine main is 15Kbtu ducted and the one in the bedroom is 13.5Kbtu non ducted and has 5 outlets. One straight down like the dump on the main one. then one on each side facing front or back and side to side. You can open or shut these as needed. As far as which one to get thats a personal choice. I would now after the fact get the heat strip model instead of just plain ole' AC. That way you will have that option of heat in the bedroom also.
randy
PS I recently posted some mod updates on my webshots, I have a picture of the Dometic 13.5K Penguin inside AC shroud on there.

[smiller]

I would have liked the heat strip option too but it wasn't available for the Penguin (Dometic found out that it didn't mix with the low-profile air handler, not enough room and sometimes parts melted), so don't feel bad that you didn't get it because you couldn't. But I think heat is available with the newer Penguin II model, not sure. In the end I don't think I really miss it because a small ceramic heater works just as well and is quieter.

[SAABDOCTOR]

I GOTTA AGREE WITH THE NOISE ISSUE! except i am bassackwards the 3750fl the main unit is in the bed room so that one stays off at night that's the main reason i put the second one in

[Scarpo]

I was also thinking of installing a second AC in my 3685FL, right now there is a fantastic vent where the AC would go. The box with the line voltage pre-installed wiring is right there also but where will the thermostat go? I suspect where the control for the fantastic vent presently is.

[JRTJH]

Originally Posted by Scarpo

I was also thinking of installing a second AC in my 3685FL, right now there is a fantastic vent where the AC would go. The box with the line voltage pre-installed wiring is right there also but where will the thermostat go? I suspect where the control for the fantastic vent presently is.

Many "add-on" air conditioners have the thermostat/fan speed controls in the overhead shroud. There are some that are wired into the existing thermostat, others that have a separate thermostat. Pretty much your choice which way you go, but keep in mind that if you select the overhead control model, once you install it, you connect the electricity and turn it on. If you select one with a separate wall mounted thermostat, you've got to figure out how to run the thermostat wiring which may get tricky.

While I'm sure someone has successfully done the third type of installation, I'd think that trying to wire it into the existing thermostat and control both from the same wall mount would probably be better left to the factory. They install that type before the walls go up and the ceiling goes on. It can be done, but at what cost (skinned knuckles, choice words, hiring someone to fix the problems) ????? That type installation probably isn't for the average "do it yourselfer"

[smiller]

I think the best thing to do is to just use the thermostat that is built into the unit (for the typical 2nd A/C in the bedroom.). You could mount a wall thermostat but running the wires may be fairly difficult, and I'm not sure why it would be worth the bother to have a thermostat on the wall just a few feet away from the thermostat on the unit. The other option is to try to wire it to the existing thermostat but that probably wouldn't work well at all because you would need to offset one unit or the other temperature-wise because otherwise one area or the other would likely be too hot or cold, if trying to run off of a single setting. The last option would be to install a true dual-zone thermostat system but really... why bother...

[Scarpo]

It's not that simple on my unit, the factory AC in the bedroom and the wall stat that also controls the furnace is in the kitchen where the second AC would supply air to. I would have to relocate the existing stat to the bedroom and use unit mounted controls for the second AC in the kitchen / Living Room. The controls part is easy, I am in the AC business but running the wires so they are hidden isn't.
I guess I could use a new stat with a wireless sensor mounted in the bedroom. That would leave the wires where they are and sense the correct room. Then use the unit mounted controls for the new unit in the living room.

[JRTJH]

Originally Posted by Scarpo

It's not that simple on my unit, the factory AC in the bedroom and the wall stat that also controls the furnace is in the kitchen where the second AC would supply air to. I would have to relocate the existing stat to the bedroom and use unit mounted controls for the second AC in the kitchen / Living Room. The controls part is easy, I am in the AC business but running the wires so they are hidden isn't.
I guess I could use a new stat with a wireless sensor mounted in the bedroom. That would leave the wires where they are and sense the correct room. Then use the unit mounted controls for the new unit in the living room.

Most people who install a second A/C use it as an auxilliary unit, only running it when the factory unit is not sufficient to cool due to high outside temps, or to cool only the "sleeping area" at night. As such, the added A/C is a "stand alone unit" that augments existing cooling capacity, not actually replacing it.

Unless you're looking at adjusting thermostats to different temps when running both A/C's, having a ceiling mount internal control on the front A/C wouldn't matter that much. At night, when you're only running the front A/C, the location of the thermostat for the unit that's turned off is not an issue. During the day, if you only run the ducted A/C from the bedroom, then the kitchen thermostat will control the entire trailer's temp. If you moved that thermostat to the bedroom and then increased the heat load in the kitchen (cooking, etc) the bedroom thermostat probably wouldn't adequately sense the increased temp because of the trailer layout and you'd wind up much warmer in the living area before the thermostat called for cooling. I don't think you'd like the wide temp swings before cooling begins. Additionally, when you do turn on the second A/C for supplemental cooling, it will only come on when the temp is higher than it's setting, so if it's relatively close to the setting on the kitchen/bedroom thermostat, it'll only balance the temperature in the trailer, not "fight against it"

Of course, if you sleep with the bedroom door closed, you wouldn't get any A/C into the bedroom from a non-ducted A/C mounted in the forward living area anyway.

I recall several discussions about trying to install an additional ducted unit and many have said it isn't possible. Of course most of them have trailers with the bedroom forward. There may be a difference in how your ducting is installed, but probably not. Do you plan to install a second unit into the ducting? or just a "stand alone" unit?

[SAABDOCTOR]

HI scarpo i did not relise you had a front living room unit too. what i did in mine was put the second a/c in the kitchen and i have one of those small fans that mount in the doorway that blows a nice bit of cool air in the bedroom with out the noise. but i never close the bedroom door. no kids and the dogs water bowl is in the bathroom so far it has worked fine for the evening. in the hot days we run both. enjoy the fans are avalible at wallmart and target. or any store that sells wood type stoves

[Jim & Kay]

I didn't realize there was 2 separate threads on adding the 2nd AC (under fifth wheels). So I decided to add a 2nd post that I formerly had added there.
We have our second AC but haven't installed it yet. It is a Coleman Power Saver and the specs are below. It does have the heat strip included. And yes I'll do the installation myself.


SPECIFICATIONS MACH III POWER SAVER 8633
Cooling Capacity (Nominal BTUH, as
compared to Mach 3 Plus) 102%
Heating Capacity, Electric Heat Strip (BTUH) 5,600*
Running Watts/Cooling (1) 1,147
Running Watts/Cooling (2) 1,355
Running Watts/Heating (3) 1,800
Electrical Rating 115V 60 Cycles 1 Phase
Locked Rotor Amps (cooling) 48.3
Approx. Full Load Amps Cooling 10.2
Heating 16.0
Evaporator Air Delivery CFM High Speed 310
Installed Weight (pounds) 92.5**
Dimensions: Height x Width x Length 13.5" x 26" x 37"

• Optional heater assembly.
**Installed weight will vary with Ceiling Package Option.
(1) Tested under the following conditions: Cooling A.R.I. Standard
Condioning 80° F. DB/67° F. WB Indoor, 95° F. DB Outdoor at 115 VAC.
(2) Tested under the following conditions: Cooling A.R.I. Standard Conditioning
95° F. DB/67° F. WB Indoor, 120° F DB Outdoor at 103 VAC.
(3) Tested under the following conditions: 47° F. Outdoor Temperature

MACH III POWER SAVER
102% Cool—30% Less Power!
• Uses less power, so there’s more electricity
for your other appliances.
• But here’s the real shocker: it actually
delivers more cooling than a standard
13,500 BTUH air conditioner.
• Even starts in severe desert conditions,
when many other RV A/Cs won’t.

I just copied & pasted the info from the product page .

[f350chief]

Just returned from trip to Myrtle Beach where I used my newly installed 2nd A/C. I will not purchase another fifth wheel camper without one. I tried cooling my camper on the original a/c unit and it got to 80 degrees inside with an outside temperature of 91. After I turned on the second a/c unit it cooled the inside temperature down to 71 degrees in about 2 hours. In my opinion a secons a/c unit is a must.

[byrdr1]

Originally Posted by f350chief

Just returned from trip to Myrtle Beach where I used my newly installed 2nd A/C. I will not purchase another fifth wheel camper without one. I tried cooling my camper on the original a/c unit and it got to 80 degrees inside with an outside temperature of 91. After I turned on the second a/c unit it cooled the inside temperature down to 71 degrees in about 2 hours. In my opinion a secons a/c unit is a must.

X2,
we used ours most everyday at WillowtreeRV in Longs, SC this past week during the day turned it off at night.
randy