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Old 09-25-2020, 08:53 PM   #1
Last2Die
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3rd AC

Hi everyone. My unit is wired for a 3rd ac unit but how does it work..? After installing on the roof and wiring it in does it come on with the living room ac..? Would all 3 work when hooked up at a camp ground ?

Curious, looks like were going to keep our unit for a while and were going to do some additions.

Thanks

Tony
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Old 09-26-2020, 04:53 AM   #2
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Hey, Tony. I'm looking into this too. I have heard that the 3rd AC and the bedroom AC alternate in the normal setup. I would rather be able to run all 3 at once, so I'm thinking of finding the wiring to the 3rd AC behind the basement and run a separate, maybe 30 AMP, service to feed it and any additional power requirements. I read it somewhere on here, but don't remember exactly where, that a few have done this and it works very well. We only need the additional cooling when first setting up. After a few hours, the unit gets down to temp and has no problem keeping up even in hot Florida temps. Just the thermostat is a problem now, but that's another story.
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Old 09-26-2020, 06:39 AM   #3
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If you add it as intended then yes it switches between Bedroom and teh 3rd AC. Folks have installed it on a separate line an plug. So they have a 30 Amp plug to also plug into the pedestal.

Search the forum for 3rd AC and you should find out how they did it
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Old 09-26-2020, 08:24 AM   #4
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More than a few of us have run the 3rd A/C completely independent of the coach wiring and it works exceptionally well. If yours is prewired, trace the wiring to a point where you can separate it out and run its own plug on side of trailer. Then you can run a separate extension cord to the campground pole and plug it into the 110volt 20amp plug.


This setup allows you to run 3 A/Cs at the same time on 50/30/20 amp poles and 2 A/Cs at same time on 30/20 amp poles.


It is also a secondary security if you have puppies in the trailer as at least one A/C will be independent of the trailer wiring if something goes wrong with same.
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Old 09-26-2020, 08:51 AM   #5
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I found the power sharing unit on mine behind a return air vent next to the door. I disconnected it there and ran a line to the basement, installed a 30amp breaker and then to a 30amp plugin that I installed next to the convienence center. Now we can run it off the 30 amp outlet on the pole or, using dog bones from the 20amp outlet on the pole.
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Old 09-26-2020, 12:07 PM   #6
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So basically find where the 3rd ac wiring is trace it down and disconnect from breaker box and wire it in with an extension cord ..?
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Old 09-26-2020, 12:48 PM   #7
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You really need to find the switching unit and disconnect it there, otherwise you will probably still not be able to run all three at once.
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Old 09-26-2020, 03:12 PM   #8
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I'm no help here but it seems like you'd need to be in the pits of hades to need a 3rd ac. My 41ft 384br has been through multiple days around 100 and stays cool enough with 2 ac.
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Old 09-26-2020, 03:59 PM   #9
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Both of our home bases have no shade for the rig. Due to the humidity, our spot in Kansas had a couple of months with the heat index around 110 and while it doesn't make a lot of sense (except the two AC's don't run max out all the time) we actually have saved several hundred dollars on electricity with the third AC. Our homebase in New Mexico was well over 100 when we left and then went to around 118 for a month or so. So yes, the devil visits us when he wants to cool off.
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Old 09-26-2020, 07:37 PM   #10
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Quote:
Originally Posted by Fish View Post
I'm no help here but it seems like you'd need to be in the pits of hades to need a 3rd ac. My 41ft 384br has been through multiple days around 100 and stays cool enough with 2 ac.
There are areas where, if your stuck, you need three (Carlsbad, NM desert during the summer for example). And there are LOTS of places where you need two when your on a 30/20 amp site with no shade.

That's the real advantage of the independent power to one of the A/C units (IE: having two A/Cs on a 30/20amp site).
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Old 09-27-2020, 04:56 AM   #11
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Tony, as I understand it, there should be a junction box somewhere behind the basement wall that the wire from the pre-wire in the ceiling (ours has a maxx air fan and junction box with blank plate on the ceiling), meets with the electric from the breaker box for the bedroom AC. If I'm correct, the normal installation requires some sort of switching mechanism to route power to either the bedroom AC or the 3rd AC and this junction is where it should be installed. I haven't taken the time to hunt for it, but on our unit I think it is going to be behind the basement wall under the stairs to the bedroom as the breaker/fuse box is very close to there.
If this is correct, I intend to run from this junction to a 30 amp receptacle on the side of the rig which can be plugged in at the cg pedestal either 30/20 amp with dog bone to power the 3rd AC.
As Jim said, we would be able to run 2 AC's on 30/20 amp site, and 3 AC's on a 50 amp site if needed. Seems to be the best of both worlds.
Incidentally, I'm intending to use the 30 amp because I also want to run some outlets into our garage area under the rear den. We have the Mor/ryde pull out tray and I could use an outlet or two for a small heater, and also for a freezer and dehydrator in the winter time during hunting season. There's lights down there but no 120 vac power right now.
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Old 09-27-2020, 09:22 AM   #12
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Just remember to put a breaker on that new line since it won't be going thru your main box.
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Old 09-30-2020, 01:20 PM   #13
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I met another Montana owner who had the 3rd unit connected to same circuit as the fireplace as they don’t run both of those at the same time. Otherwise it alternates with the bedroom unit.
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Old 09-30-2020, 01:26 PM   #14
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I’m not an electrician by any means but I did run my ATS with help of course. At some point either running a separate line to plug into the pedestal or wiring it to something else I’ll need to figure out.
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Old 09-30-2020, 01:48 PM   #15
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Quote:
Originally Posted by Last2Die View Post
Hi everyone. My unit is wired for a 3rd ac unit but how does it work..? After installing on the roof and wiring it in does it come on with the living room ac..? Would all 3 work when hooked up at a camp ground ?

Curious, looks like were going to keep our unit for a while and were going to do some additions.

Thanks

Tony
Looks like you have the unit with the bathtub and not the residential refrigerator? If that’s the case you also have the on demand hot water heater. Do you use an installed dryer? If no dryer problem solved, use the dryer breaker in the power distribution panel (120vac 20amp). The switch is located behind the basement panel on the door side where your spare tire crank is mounted. Remove the switch should be 3 wires attached to it and connect the bedroom unit to its power wire from the breaker box (bypassing the switch). Lastly run a new wire from the dryer circuit breaker down to where the switch was and connect it to the remaining wire that you removed from the switch. I’m assured you have some electrical knowledge and a voltmeter. Make sure power is off to do this. Relabel the dryer breaker A/C 3. Your done and you can run all 3
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Old 09-30-2020, 01:50 PM   #16
Last2Die
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Originally Posted by ingalmi View Post
Looks like you have the unit with the bathtub and not the residential refrigerator? If thats the case you also have the on demand hot water heater. Do you use an installed dryer? If no dryer problem solved, use the dryer breaker in the power distribution panel (120vac 20amp). The switch is located behind the basement panel on the door side where your spare tire crank is mounted. Remove the switch should be 3 wires attached to it and connect the bedroom unit to its power wire from the breaker box (bypassing the switch). Lastly run a new wire from the dryer circuit breaker down to where the switch was and connect it to the remaining wire that you removed from the switch. Im assured you have some electrical knowledge and a voltmeter. Make sure power is off to do this. Relabel the dryer breaker A/C 3. Your done and you can run all 3
Yes dryer is installed. Yup the front bathroom.
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Old 10-04-2020, 12:59 PM   #17
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Cold A/C

Quote:
Originally Posted by Last2Die View Post
Hi everyone. My unit is wired for a 3rd ac unit but how does it work..? After installing on the roof and wiring it in does it come on with the living room ac..? Would all 3 work when hooked up at a camp ground ?

Curious, looks like were going to keep our unit for a while and were going to do some additions.

Thanks

Tony
We installed our 3rd AC where the kitchen vent was. It was supper simple! when I removed the vent it was prewired.120 volt, 12 volt and thermostat wiring. It fit directly in the same hole with no mods. Behind the fan controller on the kitchen wall where the AC thermostat is was the wiring for 12 volt and thermostat. Behind the circuit breaker control panel is where the 120 power was. It tied into a box called shedder. It shares power with the bedroom. We did not like the way it randomly rotated to ACs. So I removed the Shedder box and wired the 3RD AC to the dryer circuit breaker switch. All 3 ACs work together on 50 AMP service with no problem. On our way to Sturgis we stopped over night in Las Vegas. It was 117 degrees. We turned all 3 ACs and went to the Casino and returned in 1 .5 hours and it was, no lie 68 degrees. Absolutely cool
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