[Tim wade]

Bedroom A/C stopped working, as it should when I’m in Miami FL. Lol ( 99 #530).  I’ve installed a 3/4 ton heat pump, 9K ducted mini split unit to cool the entire coach.  I’m still in the testing phase.  The hottest it has gotten is around 85 degrees. It stayed around 78 most of the day. The front A/C is still in, but I have ducted it to the mini split also. 

The install was a little difficult getting parts. I’m pretty sure the 11 1/2 X 5 inch duct is home made at Newell. I gave up trying to find a 90 to fit on about day 3 and decided to make a supply box out of 2” fiber board. At the end of the day, I wish I would have just done this from the beginning.  I installed about 90% of the ducted mini split inside the cold air return BOX. This way, I did not have to duct any of the return air. I just made a 5” block out for part or the return. It still gets air from this side, as it is open to the BOX.  The living room air is simple, it is only two 4” flex ducts. I just bought 25’ of 4” insulated flex duct from the Home Depot. I used 7” lag bolts to mount the ducted supply with 3/8 washers and locking nuts. I probably could have gotten away with 4” lag bolts. But I wasn’t sure how far down I was going to have to go. I also reinforced these with 2X4s to make it stronger.  

It is whisper quiet! The air comes out ice cold. I do with the fan blew a little harder. It does take a few hours to cool down the coach. If anyone has any questions or suggestions please let me know. 

---

[Jack Houpe]

Well at least your not out a lot of money if you have to up the BTU when it gets hot, clean easy install. Any reason you didn't go with a 24,000 BTU unit? Does the other basement air work?

[Tim wade]

Hi Jack, yes, the other basement A/C still works great! (That is our backup for now) There are several reason I went with just one unit. I own two park model RVs in McAllen TX with close to the same square footage as our Newell. With just one unit per park model. McAllen TX is about as far south as you can go in the continental United States. I have one 3/4 ton unit in each of these park models, and even with the heat index at 120 degrees. They will keep them in the low 70s. The other reason I went with just one unit is that this unit is rated to heat and cool up to 450sq ft. Another reason is I was a bit worried about the CFMs being too low with only one 5”X11 1/2” duct. This is way above my pay grade. I researched CFMs on YouTube before purchasing. Just for a little background on me. I have owned several apartment buildings in the past and have installed probably 5 furnaces myself. I am no means a professional HVAC guy. But I have an uncle that has owned his HVAC business for over 30 years. I did work for him when I was younger for a short period of time. Hopefully this explains a little more of my reasoning behind only using one unit. Time will tell if I need more. Thanks again for the idea for using a mini split in place of the basement air Jack.

[folivier]

Nice install Tim. In researching minisplits they claim a cooling efficiency greater than what we'd expect being used to old school units. Depending on the paint color of your Newell and the windshield being non-insulated I'm surprised that a 9k unit will keep it cool. Glad it's working for you! Please keep us informed going forward.

[Richard]

Hi Tim,

I asking the questions just to fully understand what you did, reading comprehension is not my forte.

You have said cool the entire coach, does that mean the air handler feeds both the ducts for the front AND the ducts for the rear?

You said you kept the basement unit that is working. How is is ducted?

You said the bedroom unit failed. Did you move the working unit from the passenger side to the driver side. Best as I can tell, your pictures are of the passenger side, and that unit cools the front.

As usual I am confused.

[hbens]

Richard,
Thanks for asking the questions I had. As you may know (I don't recall if I told you or not) I have one compressor on my front AC that is INOP. My rear AC has both compressors working I just need to install the engineered replacement board I made from your design.
I'm contemplating if installing one mini split instead of refurbing the front AC is the way to go.

[Tim wade]

You have said cool the entire coach, does that mean the air handler feeds both the ducts for the front AND the ducts for the rear?

Yes, I have ducted both front and back A/C ducts to the one mini split.

You said you kept the basement unit that is working. How is is ducted?

Right now it is ducted into the mini split with two 4” ducts. Just as is would be ducted into the original A/C.

You said the bedroom unit failed. Did you move the working unit from the passenger side to the driver side. Best as I can tell, your pictures are of the passenger side, and that unit cools the front.

Nope, the unit I removed was on driver’s side. The passenger side A/C is still in its original position. I never removed this unit to do the install.

Hope this answers some of your questions. There is a lot going on here. And some things are hard to explain in writing. I will do the best I can though. Thanks

[Richard]

Perfect explanation

[hbens]

Tim wade pid='58629' dateline='1678934630']

The install was a little difficult getting parts. I’m pretty sure the 11 1/2 X 5 inch duct is home made at Newell. 

Tim,You are right. The duct is custom made for Newell. This is off the duct attached to the street side (rear) AC.      
I'm replacing my basement air now. I'll post my results when I'm done.

[Tim wade]

Hi Hank and Natalie, I’m sorry I haven’t had time to update this thread. But I still think one ducted mini split would keep the couch cool. Just not a 9,000 btu unit. It works great up until it gets around 85 outside. We have some really big windows in the front of our couch as most Newells do. The bedroom stays in the mid 70s but the front of the couch will creep into the mid 80s. Hindsight being 20-20 I probably would have went with a bigger unit. But luckily, my front A/C still works great. As far as the heat pump, that works great with only one 9,000 BTU unit. But we have only tested it in 30 degree temperatures. If my front A/C goes out. I’d probably go with something like this unit. I do worry about the inverter getting too hot. I usually leave the bay door open that has the inverter. Best of luck. Let me know if you have any questions. Tim

Dual Zone 12,000 + 12,000 BTU Concealed Duct Mini Split Air Conditioner and Heat Pump Full Set with 25ft Installation Kits https://a.co/d/hvAuslO