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Adding a third A/C


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Our 41’ Exec sure could use a third A/C. Is this something that can be considered?  The front unit on our Coach is the original one and still functions fine. Rear was replaced about 10 yrs ago with a 15k unit. Both blow cold but we sure could use more cooling. Any suggestions are appreciated. 

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I simply added a portable A/C unit to mine. I don't know what all electrical/roof modifications you'd have to make to add a third roof A/C but I know it would be a very large project. Using a portable A/C just made more sense. 

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My first thought is do you have an exhaust fan ( square hole in the roof ) that you could use for the 3rd A/C? 

A 14 inch square hole is standard for the fans and roof air conditioners.                                     

My 03 Windsor has a fan right there in the kitchen but I know some of the more up scale coaches have a lot of fancy ceiling stuff up there.

In a coach like mine I'm pretty sure I could pull it off.  I have thought about adding a 3rd A/C too.  If I made the air to go into the ducts it would complicate the installation somewhat but probably still doable.    The simplest install would be with a plastic ceiling cover, it will also have a thermostat made into it. You could run a power cord on the roof or along the ceiling.   I have seen an installation on a 5th wheel where the power wireing was a totally seperate wire that they plugged into the extra receptacle on the power post.  Not fancy but it did work.

Personally  I think I run my wires inside my air ducts back to the breaker box                              Also some air conditioners are remote controlled, so all you need is 120v

Edited by Ray Davis
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Adam

   How do you vent your portable unit to outside?

Ivan

  I was thinking that also but I’m not sure if it was an option. Sure would be nice if it was framed for it and even better if the wiring was up there somewhere. I do have a Fantastic fan in the bathroom that we almost never use. Was thinking I could utilize that spot also. Ideally I would like to have it utilize the ductwork though. Might be too painful to consider. They should have built it with three units standard. Funny that a 45’ has three but a 41’ only two

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27 minutes ago, Chargerman said:

I do have a Fantastic fan in the bathroom that we almost never use.

Is that the only exhaust fan?

I have 3,   one in the toilet room another in the shower area and a Koolerator in the kitchen area.  It uses the same 14 inch opening.    If I decided to add a 3rd, the kitchen is where I would place it.

I'm of the persuasion you can't have too much money or air cond.

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40 minutes ago, Chargerman said:

Adam

   How do you vent your portable unit to outside? 

I use the window beside the passenger side captain seat. It's doable with slides in and fits nicely with slides out. 

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Thanks Adam. Something to consider

Ray

  I do have the same vents you mention and the kitchen one would be the best option. Now how to get 20 amps of power there

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3 minutes ago, Chargerman said:

Ray

  I do have the same vents you mention and the kitchen one would be the best option. Now how to get 20 amps of power there

I thought I would try running the wire inside one of the ducts to the rear and pick up power from the receptacle      for my 120v block heater.   I think others have punched a small hole in the end of the duct which hopefully will dump the wire into the space of the rear cap.   It's not going to be that easy though,  it'll require some fishing.

A thermostat wire could be run in the duct too.

Bill G,  ( RIP )  was an innovative man who figured out a way to mount a small window A/C in the bedroom in a way that you couldn't tell it outside.  Plus it was powered by his inverter.

Someone may have pictures 

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I would be a bit concerned withour roof bracing with the heavy AC unit on our roads. Not sure if the kitchen fan has any but I would try a stud finder to see where they are above the duct. The wiring, I think, could be fed through the duct to the rear breaker box and steal the 12v and thermostat connection on its way from the rear unit.

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2 hours ago, Ray Davis said:

I thought I would try running the wire inside one of the ducts to the rear and pick up power from the receptacle      for my 120v block heater.   I think others have punched a small hole in the end of the duct which hopefully will dump the wire into the space of the rear cap.   It's not going to be that easy though,  it'll require some fishing.

A thermostat wire could be run in the duct too.

Bill G,  ( RIP )  was an innovative man who figured out a way to mount a small window A/C in the bedroom in a way that you couldn't tell it outside.  Plus it was powered by his inverter.

Someone may have pictures 

Bill had a 40' Dynasty Diamond III.  The small AC unit was mounted in the bedroom - PS on the dresser where he would open the window to vent the box built around the AC unit and the water drained outside.  Pictures are worth a thousand words.  The AC unit also had a hand held remote control with a timer.  So he could operate form his bed.  He loved it for dry camping and ran it on the inverter with a bank of 8 AGM batteries.

 

25 Interior Bedroom 2.jpg

26 Interior Bedroom 3.jpg

38 Exterior Rear.jpeg

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Yes, he had louvers that filled the gap when the window was slid partway open to allow airflow but kept rain out.  I'll see if I can find a better exterior picture.

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If you Google, there are, I think….from some past curiosity, some enterprising folks that have done that.  

Here is where I get a little fuzzy….so help me out.  I, too, feel the need for a third AC.  The simple BTU/ COACH length calculations show 30% more BTU/ft.  Tiffin makes a 40, or did, with 3 AC and a W/D….maybe even a 38 if you want less length.  

What I recall from a discussion with a very knowledgeable Lippert Penguin tech was that on my Camelot, there are 2 duct runs.  Maybe I misunderstood.  My concept was the front and rear AC had two discharge outlets or ducts.  They ran side to side.  Their was a long duct running on the drivers side from the front to the rear.  So if you turned on the front, you got air all the way to the back.  On the passenger side, the long duct was blocked or cut off in the bedroom.  I have a center shower in the hallway on the passenger side.  That has a skylight and prevents the passenger side duct from running full length from the front to the rear.  The duct starts over the passenger side vanity in the wall and then goes to the front.  Monaco made 2 versions of the tag.  One with a rear shower.  That version had full length ducts.

AS I SAID….that was my “concept”, so don’t take it as fact.  But I have read write ups of adding a center unit and the “creative” way to get power (115 VAC) to the roof from the main panel.  Power would be an issue, but I think that the shorter 40’s have a slot for a rear AC and you could install a Intellitec AESS module.

 

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Tom brings up a good point, that point being does the duct run from the new 3rd A/C location to where ever you want the wire to go.   I too recall that the passenger side duct does not run full length, shower is in the way.

I still believe we can use the duct as a wire passage, just gotta use the correct one.

Edited by Ray Davis
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That installation Bill did was Perfect. Saw it many times. IF i was considering adding a AC, i would contact, https://eliternr.com/ or Elkhart Sales and Service. It's what they do. Offer to pay a consulting fee. I did it many times while full timing 10 years. Takes all the lip slapping,opinions, and speculation out of it.

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While I respect what Bill did I wouldn’t consider installing a window unit. Thanks for the contact references. I will reach out to them to see what they would recommend. 
 

Thank you!

1 hour ago, Ray Davis said:

Tom brings up a good point, that point being does the duct run from the new 3rd A/C location to where ever you want the wire to go.   I too recall that the passenger side duct does not run full length, shower is in the way.

I still believe we can use the duct as a wire passage, just gotta use the correct one.

I am pretty certain my duct runs full length. Front and rear share the same duct. I will confirm today by running one unit and shutting the registers at that end to confirm the air flows to the other end

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53 minutes ago, Chargerman said:

While I respect what Bill did I wouldn’t consider installing a window unit.

I did consider it but that's my emergency escape window.   Just about anything Bill did I was interested in.

Being able to sleep without running the generator was a real break through to me.  I have run the gen all night        many times just to have A/C.   As a kid we didn't have A/C, I have gotten soft,  couldn't live without A/C now.

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Our 2006 Dynasty has 3 A/C's. Trying to figure out the air distribution for each unit I did a little experimenting on our last trip. It appears the coach has a central duct running the length of the coach (with the exception of the outlet in the toilet room). I found that running only the rear A/C will distribute air to the front vents especially if the rear and center vents are closed. This is also true when running the front unit, air will flow to the rear of the coach. Airflow is highest closest to the A/C unit being operated and selecting additional units adds volume to the duct thus increasing total airflow with the highest airflow nearest the units that are operating. 

This coach is new to us so we are still learning 🙃

Thank you for the great forum and great folks that are contributing every day!

Dan

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The Discovery group I belonged to had a gentleman that installed a 12,000 btu mini split in his Discovery. They didn’t use the front tv above the dash so that is where he put it. He ordered a kit from Amazon that was pretty reasonable and spent a lot of time doing a nice install of it. We went to a rally last year and I saw it first hand. It was very quiet and he said it cooled the entire Motorhome and that they rarely turned on the rear ac. He installed the condenser in one of the storage bays outside. Here are a few pictures I found

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13958CAB-D82D-41A4-BF8D-8AE8F88F14B8.png

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My '03 41' Exec came with two factory units. I was considering removing the koolmatic in the kitchen for a 3rd unit. I went to RV Renovators in Mesa AZ and they said my idea was terrible as the roof was not braced properly. They informed me that Monaco at the time was putting the 3rd a/c bracing in the roof for future upgrades. The hole is in the center of the coach so it runs right into the duct work. They cut through the roof and dropped the new unit it. They ran the power cable through the duct work and then over to the circuit breaker panel. I believe they unhooked the receptacle for the block heater which I've never used anywhere. End of story the 3rd a/c made all of the difference in the world. 

Ken

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Grampy OG said....after adding the third AC to his 41 Exec.....

End of story the 3rd a/c made all of the difference in the world. 

IF we had an award for the understatement of the year, you would be a contender.  Assume that the 45 footers have TWO 15's and a 13.5 KBTU.  Add the BTU's and divide by 45....or O.996 K or 996 BTU/ ft.  In you case.... two 1r's or 30 divided by 41 is  0.732 or 732 BTU/ft.  if you compared a 45 to your 41, that is a 1/3 or so increase in cooling.  BUT, if you added in the 13.5 K BTU, you have 1,061 BTU/Ft or 45% increase.  THAT IS AWESOME.  I ought to do that....but haven't.  GOOD DEAL...

Thanks for sharing that...

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