Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 09-01-2014, 09:19 PM   #1
Senior Member
 
akeyzoo's Avatar
 
Join Date: May 2013
Posts: 959
Thoughts on adding a 3rd rooftop AC

Folks,
My Revolution 40L currently has 2 13.5K rooftop units. There is a single 2x8" duct running the length of the coach that has multiple roof vents for cool air. Both AC units work, and blow out cold air. On hot days, however, it isn't enough. I was just camping in 90-95 degree heat, and 81/82 was about the best I could hold inside the coach.

I am tempted to add a 3rd unit. I have already found an empty breaker location on the EMS, originally slated for the nutone that I do not have, it is a 20A breaker (a 2 pole 15-20). I CAN figure out how to run the wiring.

A few more notes. My two units are located such that my first is about 25% from the the front of the coach, and the second about 60%. This actually makes sense when parked, as the rear bedroom has fewer windows and requires less cooling capacity. When driving with the CAT below you, the bedroom does stay warm tho.

I have 3 fantastic fans. Bathroom, Shower and Kitchen.

As far as I know I have 2 options for rooftop units. Tie into my existing ductwork or have a standalone direct vent.

It would make sense to have the 3rd unit towards the rear of the coach, but I would either have to cut a hole to tie into the existing ductwork OR put the direct vent at very rear of coach and block off the ductwork at the new 3rd AC unit.

OR, place a standalone unit in place of the fantastic fan in the kitchen. This would require relocating the satellite a bit and slightly more difficult wiring.

Is it worth it to tie into the existing ductwork, or does the duct not have the capacity to run a 3rd system?

Run a dedicated stand alone at rear of coach, direct vent in bedroom only?

Looking for ideas. I am handy and can get this done either way.

For those with 3 roof AC's, how large is the duct if you know, and how many registers?

My gut tells me direct vent, although loud, it seems very efficient. I was playing with my existing AC and removed a panel essentially letting it direct vent into coach. That was a lot of cold air for sure!!


Chris
__________________

__________________
------------------------------------
American Revolution 40L CAT C9
Samsung 197, TireMinder, Ready Brute Elite with Wrangler
akeyzoo is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 09-01-2014, 09:34 PM   #2
Senior Member
 
Join Date: May 2013
Location: San antonio, TX
Posts: 597
I am surprised your two ACs don't cool the coach down. Although we have three ACs, the thirds is normally not needed unless we run outside temperatures well over 100 degrees. You may want to get you units checked. Do you get 65 degree air out of the registers?
Was there an option on your coach for 3 ACs? If so, the wiring may be in place for a third unit.
__________________

__________________
USAF Retired
2000 Prevost Marathon H3-45
Towing 2006 Nissan Maxima
Peralko is offline   Reply With Quote
Old 09-01-2014, 09:40 PM   #3
Senior Member
 
akeyzoo's Avatar
 
Join Date: May 2013
Posts: 959
Peralko,
The air out of the ac units is plenty cold. On 95 degree+ days I can't keep her in the 70's inside. Based on research (I searched prior to posting), lots of folks have a 15-20degree maximum cooling. In other words many can't cool inside to be more then 20 degrees cooler then outside air.

Thanks
Chris
__________________
------------------------------------
American Revolution 40L CAT C9
Samsung 197, TireMinder, Ready Brute Elite with Wrangler
akeyzoo is offline   Reply With Quote
Old 09-01-2014, 09:43 PM   #4
Senior Member
 
Mr_D's Avatar
 
Solo Rvers Club
iRV2 No Limits Club
Join Date: May 2011
Location: Vancouver, WA
Posts: 28,423
Quote:
Originally Posted by Peralko View Post
I am surprised your two ACs don't cool the coach down. Although we have three ACs, the thirds is normally not needed unless we run outside temperatures well over 100 degrees. You may want to get you units checked. Do you get 65 degree air out of the registers?
Was there an option on your coach for 3 ACs? If so, the wiring may be in place for a third unit.
Me to! In 95 weather we can easily get the temps down into the 70's running only one of our 13.5 heat pumps. Running both of them gets the bedroom too cool so I usually set it for 76-78 and the front for 72.
The specs for RV air cons or heat pumps is to cool the outlet air 20 less than outside ambient which may or may not be enough depending on the insulation in your rig. Ours is well insulated and has double pane windows too.
__________________
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft
Charter Good Sam Lifetime Member, FMCA, SKP
RV'ing since 1957, NRA Benefactor Life, towing '14 CR-V
Mr_D is online now   Reply With Quote
Old 09-01-2014, 09:53 PM   #5
Senior Member
 
Starsekr's Avatar
 
Join Date: Feb 2014
Posts: 340
Mr. D. I'm envious. My 2005 Winnie Adventurer 37 can only drop temps about 22 degrees, with everything closed up and a reflective blanket on the front window. 107 in Laughlin,NV today, 85 in the coach. This is with both stages of the basement air running. Wish the insulation was better. :-[
__________________
Starsekr is offline   Reply With Quote
Old 09-01-2014, 10:03 PM   #6
Senior Member
 
akeyzoo's Avatar
 
Join Date: May 2013
Posts: 959
My rig appears to be well insulated with double pane windows, but has lots of windows. :-)

Does your rig have a roof vent work or does ac direct vent into coach?

Chris
__________________
------------------------------------
American Revolution 40L CAT C9
Samsung 197, TireMinder, Ready Brute Elite with Wrangler
akeyzoo is offline   Reply With Quote
Old 09-01-2014, 10:11 PM   #7
Senior Member
 
Join Date: Jun 2014
Posts: 131
Could you replace one of the existing A/C units with one that puts out more BTU's?

Just a thought

Bill
__________________
superlucky is offline   Reply With Quote
Old 09-01-2014, 10:48 PM   #8
Senior Member


 
Join Date: Aug 2011
Posts: 3,282
Thoughts on adding a 3rd rooftop AC

Quote:
Originally Posted by akeyzoo View Post
My gut tells me direct vent, although loud, it seems very efficient. I was playing with my existing AC and removed a panel essentially letting it direct vent into coach. That was a lot of cold air for sure!!


Check to be sure none of the ductwork has debris, or is collapsing. Sometimes "braces" have to be made to hold the ducting completely open to allow maximum airflow.

Read these other threads which are relevant to your situation...

Holiday Rambler AC Duct work

Poll: 2nd A/C ducted or nonducted

How Cool Can You Stay?
__________________
pasdad1 is online now   Reply With Quote
Old 09-01-2014, 11:01 PM   #9
Senior Member
 
TurtleKent's Avatar
 
Tiffin Owners Club
Winnebago Owners Club
Freightliner Owners Club
Join Date: Feb 2011
Location: The Buckeye State
Posts: 492
Send a message via AIM to TurtleKent
Suggested reading

Adding a roof air as an adjuct to basement air

I don't doubt a bit that you need more cooling. I added a roof air on my 40' Horizon, as the basement a/c was not sufficient. I blame 3 slides and dark full-body paint as contributing factors. My install was a little different than John's, as I cut thru the roof rather than sacrificing one of the Fantastic fans. A welcome addition, glad I did it. The most challenging task was getting the 100# a/c to the roof. Good luck.
__________________
Kent & Sue & Pecos
2010 Allegro Bus 43QRP
Formerly 2004 Itasca Horizon 40AD
TurtleKent is offline   Reply With Quote
Old 09-01-2014, 11:09 PM   #10
Cat
Senior Member
 
Join Date: Jan 2005
Posts: 534
I've struggled with the heat -just not enough cooling for size area. And I investigated installing a third unit on the roof back in the back exactely for the same reasons you mentioned, most of all it made sense. What I found was Fleetwood puts reenforcements around the square areas where the A/c. sit. The reenforcements tie in to the cross supports. Is this reenforcements really necessary? I don't know. I was going to run a separate power out and run it directly to the 20 amp power pedistals that most power pedistals have. If the pedistal didn't have extra 20 amp plug in I would just plug back in to one of my outside coach plugs This way I wouldn't have to mess with tying the A/C power in to the coach wiring.
In the end I didn't do it, instead I bought a portable A/c 12,000 btu with dual hoses. This keeps the motorhome cool (72-75) even in Tucson Az in the summer. One thing I did notice the added air doesn't have to run often to keep the temperature down. To me that just shows the two 13.5 I have will almost keep up with the heat gain but slowly they get overwhelmed and the third A/C just runs enough to keep down the heat gain. I also thought of replacing both with Atwood air command A/C they are rated 15000 btu but Atwood says they are really 18000 Btus . Two 18000 btu A/c might be enough might be. Good luck.
__________________
Cat is offline   Reply With Quote
Old 09-02-2014, 12:44 PM   #11
Senior Member
 
akeyzoo's Avatar
 
Join Date: May 2013
Posts: 959
Thanks for links ya'll.

Cat - wish I knew if going to 2 bigger units would work. If I KNEW it would, that would be a no brainer.

Anyone made the switch from 13.5K units to higher capacity with success?

Chris
__________________
------------------------------------
American Revolution 40L CAT C9
Samsung 197, TireMinder, Ready Brute Elite with Wrangler
akeyzoo is offline   Reply With Quote
Old 09-02-2014, 01:04 PM   #12
Senior Member
 
codgerbill's Avatar
 
Winnebago Owners Club
Join Date: Sep 2007
Location: Ann Arbor Michigan
Posts: 777
Just a suggestion, Buy a portable A/C (10,000-12,000-13,000 BTU) and exhaust it out a window. The upside is that you take it with you when you know you are going to hot weather climate, otherwise it is stored in the basement. We can also use it to cool our sun room at home. in hot weather We put ours behind the drivers seat and so there is negligible loss of space. We only bring it a couple times each year.
__________________
2005 Suncruiser
Banks Powerpack
Chocolate lab (Buster)
2007 Jeep Wrangler
codgerbill is offline   Reply With Quote
Old 09-02-2014, 01:12 PM   #13
Senior Member
 
akeyzoo's Avatar
 
Join Date: May 2013
Posts: 959
Seems many of the links above confirm my suspicion that a direct vent AC is the way to go.

So, add one in my cluttered mid section to replace a fantastic fan near kitchen?

Or add one in bedroom at rear of coach? Would need to cut a new hole and likely block off the last vent. Another consideration with this approach is that the temp probe for my zone 2 thermostat is in bedroom. I am guessing no biggie as I see the 3rd unit as the final option is really hot weather.

Placing unit in rear also makes wiring a breeze as I can use a conduit in the rear closet area and then shoot under the bed to the EMS center.

Now, which unit to get... Penguin 2 looks nice and low profile at 13.5K.

Oh, and I need to figure out how to safely get this puppy onto the roof. I have 4 post vehicle lifts, and could roll one out next to coach if needed ;-)

Chris

Chris
__________________
------------------------------------
American Revolution 40L CAT C9
Samsung 197, TireMinder, Ready Brute Elite with Wrangler
akeyzoo is offline   Reply With Quote
Old 09-02-2014, 02:12 PM   #14
Member
 
jax1911's Avatar
 
Join Date: Jan 2014
Location: Jacksonville, Florida
Posts: 30
We recently traded in an ALLEGRO 32 CA that had (2) 13.5 A/C units that worked very well until we hit areas in the South West during July and August.

By late morning the temps would start to rise and the inside temp would be over 80 degrees. Since we were on the road and had a couple of months left on our trip I went to home depot and picked up some Reflexit (?) for the windshield and it helped but did not get the temps low enough so I bought some more and used it in all of the windows in the coach which had lower the temps down to where it was comfortable inside.

We also noticed that the cabinets that run along both sides of the coach were very hot inside so we plan to put insulation on the back walls.

I would start by using the Reflexit on all of the windows and insulating the cabinets to see if that solves the problem, its an inexpensive fix and takes no time at all, if the temps don't get low enough then I would look at a third unit.

Good luck and keep us posted.
__________________

__________________
jax1911 is offline   Reply With Quote
Reply

Tags
roof



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Adding a 3rd AC to a Kountry Aire dynacopas Newmar Owner's Forum 10 09-04-2014 04:21 PM
Travato and Adding a Spare Tire tjjeeper Class B Motorhome Discussions 0 07-11-2014 11:32 AM
Your Thoughts about Summit Products Premier Stainless Steel Trim danleininger Newmar Owner's Forum 24 06-03-2014 11:17 PM
Need help, all thoughts welcomed 98723A Travel Trailer Discussion 10 06-01-2014 01:26 PM
3rd pressure coolant hose on ISL 425 on 08-09? kraig Alpine Coach Owner's Forum 12 11-07-2013 12:34 AM

» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 11:55 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.