Anyone heard of adding a 3rd roof AC?

[ChiefBob]

I have a devil of a time cooling my coach when tailgating in +95 degree heat. I've done all the fixes/hacks I could find on forums. When headed to pick up the coach on campus on Sunday morning I saw a coach leaving that had a third AC installed in place of the vent, likely over the kitchen. Looked strange because it was off to one side but I'm intrigued.

Anyone ever seen or done this? Thanks

[16ACE27]

Originally Posted by ChiefBob

I have a devil of a time cooling my coach when tailgating in +95 degree heat. I've done all the fixes/hacks I could find on forums. When headed to pick up the coach on campus on Sunday morning I saw a coach leaving that had a third AC installed in place of the vent, likely over the kitchen. Looked strange because it was off to one side but I'm intrigued.

Anyone ever seen or done this? Thanks

Some bus chassis MHs have 4 or 5 installed. 3 is not that unusual.

[KNLAdventures]

Originally Posted by ChiefBob

I have a devil of a time cooling my coach when tailgating in +95 degree heat. I've done all the fixes/hacks I could find on forums. When headed to pick up the coach on campus on Sunday morning I saw a coach leaving that had a third AC installed in place of the vent, likely over the kitchen. Looked strange because it was off to one side but I'm intrigued.

Anyone ever seen or done this? Thanks

I'm also interested in adding a 3rd a/c to the roof. The issue is going to be getting a dedicated 20 amp circuit wired to that location. Our breaker panel is under the bed in the rear of the coach. 2022 Challenger 37FH

[MLP]

I have seen two coaches going down the highway with the external chords swinging in the wind. Not a good idea. I saw one in a camp site with a third AC. I asked and the installer put conduit on the roof and then down through the walls to the rear into a connector box. They plug in the power post in the 20A socket using an extension cord. Most do not have extra room in the breaker box for another breaker. It worked well.

[ChiefBob]

Thanks for the comments. I have two main concerns:

1. The roof weight in the middle of the "unsupported" wall where the full wall slide is. At least going down the road the slide is in and may add some stability/strength.
2. The power issue already mentioned above. I had a separate power feed to my second AC on my 5th wheel but it was prewired to the breaker box. I would not be opposed to a separate power supply if is didn't look jerry-rigged. I could possibly run conduit long the roof to the back over the closet and tap into the old dryer circuit. I removed the w/d for more storage room.

[Mousemate]

what size units are on the roof?
Furrion sells a 15500 btu units now

[ChiefBob]

They are 15,000 BTU.

[Jimbo56]

Originally Posted by MLP

I have seen two coaches going down the highway with the external chords swinging in the wind. Not a good idea. I saw one in a camp site with a third AC. I asked and the installer put conduit on the roof and then down through the walls to the rear into a connector box. They plug in the power post in the 20A socket using an extension cord. Most do not have extra room in the breaker box for another breaker. It worked well.

This is similar to how I added a 2nd unit. But it will not run on the genny .

[ChiefBob]

Thanks. I only need the third AC when parked and primarily at tailgates in the brutal Texas heat on August, September and early October.

[Beau388]

Originally Posted by ChiefBob

I have a devil of a time cooling my coach when tailgating in +95 degree heat. I've done all the fixes/hacks I could find on forums. When headed to pick up the coach on campus on Sunday morning I saw a coach leaving that had a third AC installed in place of the vent, likely over the kitchen. Looked strange because it was off to one side but I'm intrigued.

Anyone ever seen or done this? Thanks

Prevost band tour buses often have 5 roof top units depending on the number of bunks. They are wired for 2 50 amp power centers and thus have 4 50 amp circuits. Thor normally wires each roof vent for a fan. The wiring diagram for the coach will show if it exist. You can use the existing wire to pull a steel fish tape down to power center where the wire terminates. Then use the fish tape to pull the 12 awg Romex up to the vent. If you want to use the existing roof ducting for the new A/C, an electric carving knife will cut the poly foam blocks into removable blocks to access the ducts. You can wire in a sub panel if there is no remaining space in the power center.
If it sounds like I have added an additional A/C, it is because I have - changed the power center to PPS 5375, added a sub panel and A/C and changed out the inverter to a Xantrex Freedom Xi 2000.
All it takes is money and time. I did everything myself except of carrying the A/C to the roof. PPL was happy to carry it to the roof, since I bought it from them.

[ChiefBob]

Thanks Jim and Roy. Did you this to a non-traditional vent location? Mine is over the kitchen and off to the side from the factory ACs.

[Beau388]

Originally Posted by ChiefBob

Thanks Jim and Roy. Did you this to a non-traditional vent location? Mine is over the kitchen and off to the side from the factory ACs.

Not quite. We had a 30 amp coach with one A/C in the center of the coach. We live in South TX so one A/C is not enough. We now have a 50 amp coach. The coach came with 3 wired ceiling vents (14"x14") in the center of the coach. I added the bedroom Mach 8 heat pump with a separate thermostat on the outside shower wall. That is the way Plant 750 was building this floor plan in 2017 when we visited the plant. The forward most ceiling vent has the original 4 speed fan which we use in temperate climates.

The floor plan only has slides on the drivers and has a split bath and the best kitchen arrangement that plant 750 build.
The coach is a November 2015 build. Thor offered the 31S floor pan with the optional 50 amp service and second A/C in Jan 2016 for $16,000 more ours listed for.

[ChiefBob]

Thanks

[Jimbo56]

Chief, mine originally had 1 ducted 13.5 Coleman Mach 3 mounted about 2/3 back from front on roof. 8 ft in front of it was some kind of supper vent fan over the kitchen. We seldom cook inside. We took the fan out, installed another 13.5 Coleman mach3, ran wiring in a similar colored conduit across the ceiling, down the wall, thru floor into a storage bay where we located a 30 amp breaker. Then ran it out of box to a newly added 30 amp plug. Depending on the service at the campsite, the coach is plugged into 50 a (using a dog one adaptor) or the 30 A. The 2nd non ducted unit gets plugged into either the 30 a or the 20 a (using another adaptor). Using 20a the plug doesn’t get hot and I can actually cool the entire unit better with only the 1 non ducted AC.

[aznytfury]

Originally Posted by ChiefBob

I have a devil of a time cooling my coach when tailgating in +95 degree heat. I've done all the fixes/hacks I could find on forums. When headed to pick up the coach on campus on Sunday morning I saw a coach leaving that had a third AC installed in place of the vent, likely over the kitchen. Looked strange because it was off to one side but I'm intrigued.

Anyone ever seen or done this? Thanks

Actually, it's interesting that you bring this up. I have a 2017 Thor Aria 3901 with 2 factory Coleman ACs. I am thinking about adding a 3rd for the same reason (I live in AZ and it is a challenge to cool it down in the warmer months). Also, looking at the kitchen vent fan as the mounting location as well. Trying to figure out the best way to 'piggy-back' the electrical. Was thinking about using a small 20 amp ATS potentially off of the induction cooktop surface circuit since it is nearby.

[ChiefBob]

I am fortunate in the power department. We removed the washer/dryer to gain the storage space so I have access to the 15 amp dryer circuit in the now closet. I plan to run 1/2” pvc conduit from the AC straight back to the roof vent for the former washer plumbing vent. I removed the vent stack when I capped the washer drain. I will come through the side of the vent and drop into the closet, tying in to the circuit. I’m not sure how I will route the 120 volt wiring out the side of the AC unit to get it on to the roof. I will get a unit with the controls in the ceiling grill so no thermostat wiring. If I actually do this I will post pictures

[Frank@theShop]

Originally Posted by ChiefBob

I have a devil of a time cooling my coach when tailgating in +95 degree heat. I've done all the fixes/hacks I could find on forums. When headed to pick up the coach on campus on Sunday morning I saw a coach leaving that had a third AC installed in place of the vent, likely over the kitchen. Looked strange because it was off to one side but I'm intrigued.

Anyone ever seen or done this? Thanks

It would be interesting to know how it was setup as far as wiring the 3rd unit. Assuming the typical electrical circuit on a typical rig, you cannot run 3 ACs on 50 amps UNLESS you have an energy management system and that would be typically factory installed. I cannot fathom someone aftermarket installing an energy management system as the labor would be tremendous. What I have seen in the past is people running a separate 15 amp plug that is wired to the 3rd AC and which is a simple one with controls in the ceiling assembly, but I've never seen one that didn't look kind of goofy. What would be neat and more professional looking would be to have soft start kits installed on all 3 units and then you could likely run all 3 at the same time on 50 amps without an energy management system.

[ChiefBob]

The 13.5 unit I’m looking at has a soft start built in and I’m considering adding soft start to the two existing 15k’s

I acknowledge that it will look a little strange with an offset AC in the middle but I think this is what it takes to cool the rig at times.

[jawolife]

I have three AC on my Redwood. They are all factory installed and ducted. A friend of mine was impressed with the cooling efficiency on hot days and he was interested in putting a 3rd AC in as well. His Alpine had a roof vent in the kitchen. He had a 3rd AC put in place of the vent. Although it is a high ceiling, he uses a PVC pipe with a notch cut into it to turn the controls. Because the kitchen and living area are so close, he finds himself using the 3rd AC for more rapid cooling and he is quite happy with it. As for wiring, he has a separate cord dedicated to the 3rd AC. This cord is routed through the RV city connections area of the RV. Most RV parks have a 20 amp connection at the pedestal along with the standard 50 and/or 30 amp connection. He plugs in the RV 50 amp and the additional 20 amp for the 3rd AC.

His 3rd AC is offset to the roadside but it looks fine and does not cuase any problems.

[ProsperTrail]

We installed ceramic window film (Clear) on all front windows, including the windshield to almost totally eliminate the heat from the sun while driving.

You can apply same ceramic window film on side window, with or without tint, to help keep out the heat in the rest of the coach.

This also helps protect the interior from UV frying. we already replaced all the "fake leather" throughout the coach, as well as our curtains and don't want to that again anytime soon.

Vent covers over the original vents also help reduce radiant heat from getting into the coach.

I used a laser thermometer to check all around our coach for hot spots and addressed them as I found them.