Time for new AC units? Let's talk options

[eagle19952]

This deal is never going anywhere till someone that stays away from power poles,RV parks and use their bus for 20,000 miles a year. The ones I know that use their bus the most have the most trouble it seems like to me

No body ever tells if they have problems or not the few I know with mini splits it's about a 50/50 toss up.This is not uncharted waters with the mini split Ace had those in his Eagle 12 or 15 years ago, he sold his Eagle then he used roof tops on his H-40 maybe just for space I don't know

boondocking in a Prevost/GM/Eagle/MCI is like 4 wheeling in a Bentley...

[Oonrahnjay]

I will be doing my 4106 air project soon and my current favorite is > http://www.fujitsugeneral.com/PDF_06/9-12-15RLS3%20Sell%20Sheet.pdf because of the high efficiency.  ...

    Unfortunately, all 230V (or 208/230 as listed).  I know that that's more efficient, etc. but it's a deal breaker for me.

[Darkspeed]

    Unfortunately, all 230V (or 208/230 as listed).  I know that that's more efficient, etc. but it's a deal breaker for me.

Im actually going to run them off a 240VAC SW inverter from a 24VDC battery bank.

In low cool setting the 9k (12k) BTU only uses 575 watts. The 15k (18k) BTU only uses 2277 watts in full cool mode.

[Oonrahnjay]

Im actually going to run them off a 240VAC SW inverter from a 24VDC battery bank.

In low cool setting the 9k (12k) BTU only uses 575 watts. The 15k (18k) BTU only uses 2277 watts in full cool mode. 

     Yeah, the wattage figures are impressive.  I currently have a 120V inverter and a 12V battery bank -- not saying that I couldn't or I wouldn't but it seems pretty impractical. 

[andyps]

I will be doing my 4106 air project soon and my current favorite is > http://www.fujitsugeneral.com/PDF_06/9-12-15RLS3%20Sell%20Sheet.pdf because of the high efficiency.

How well insulated is your 4106? If you have the OEM single pane windows and the OEM insulation you may need a pair of the 15K BTU units.

The high efficiency units are about $1700 > https://www.theacoutlet.com/15RLS3-ASU15RLS3-AOU15RLS3-15000-Btu-25.3-Seer-Fujitsu-Single-Zone-Mini-Split-Heat-Pump-System.htm

You can get a lot less efficient units for a lot less money.

Not sure on the insulation. I think it has fiberglass insulation in a few places (where I've seen it poke out). So either that or OEM insulation. Not great either way. Also have the original single pane windows.

I definitely think I need at least 30k BTU. What's the advantage of the Fujitsu units other than efficiency? How massive is the difference between 15 and 23 SEER?

[Darkspeed]

My AC engineer buddy swears the Fujitsu are the best brand for mobile mini splits and they are good at removing moisture from the air. If you are running your split system exclusively off of a 120v/240v power pole, then there is no big seer advantage. It matters to me because sometimes I will be running off of a battery bank backed up by a small generator.

The OEM 4106 had about R3 worth of insulation in the walls, none in the floor, single pane windows, and no form of thermal isolation, so you are fighting mother nature.
Easiest thing to do to combat heat is a bright white roof. Im using Liquid EPDM on mine as it also makes the entire roof waterproof and hail resistant. > http://www.amazon.com/gp/product/B003K9XGTK/ref=pe_456950_140776490_em_1p_0_im

[andyps]

My AC engineer buddy swears the Fujitsu are the best brand for mobile mini splits and they are good at removing moisture from the air. If you are running your split system exclusively off of a 120v/240v power pole, then there is no big seer advantage. It matters to me because sometimes I will be running off of a battery bank backed up by a small generator.

The OEM 4106 had about R3 worth of insulation in the walls, none in the floor, single pane windows, and no form of thermal isolation, so you are fighting mother nature.
Easiest thing to do to combat heat is a bright white roof. Im using Liquid EPDM on mine as it also makes the entire roof waterproof and hail resistant. > http://www.amazon.com/gp/product/B003K9XGTK/ref=pe_456950_140776490_em_1p_0_im

Good info! At some point I'd love to do spray foam, but that's a lot of work to remove everything from the bus to redo insulation right now.

Our roof is currently white, but probably needs a new coat at some point soon. I'll bookmark that roof coating.

[andyps]

I've re-measured everything and read through several of the "slim duct" recessed type evaporators like this one: http://www.fujitsugeneral.com/duct.htm

It looks like these will be too big to install where my current ones are. Not to mention I think my existing ducting would be too small and restrictive for these. I'm going to see if there is any other way to make them work. Otherwise I might be stuck with the regular on-the-wall units.

Has anyone ever tapped into the existing vents (that run along the windows on both sides of the bus) with another AC unit? Maybe I could run the ducted mini-splits and duct them directly into the bus system?

Any other thoughts or options?

[gg04]

We've watched lots of people try all kinds of a/c solutions..If you really use your bus rooftops are still the easiest to maintain.. We never stay anywhere below 70 degrees. So a/Cs run... About 7years is average life. Have two new Atwood's setting here at the moment...rdw

[Seangie]

After installing mini-splits and running the gammit with those, Here's my 2 cents -

Mini splits are awesome when they work.  You really need to spend time and money on the install.  Number one issue is getting enough air to cool the external compressor unit.  It puts off a lot of heat.  Tikvah (Dave) has a single 9k unit and has to leave his bay door opened when parked.  When I had mini splits I had a hole cut into my bay door and floor of the bay with a fan forcing air down out of the bay.  I had a 24k unit and when driving it was barely enough to keep the external unit from overheating.  When parked the bay door was open.

So a cooling solution for the outdoor unit is needed.

Second -  the inside unit will collect water in a humid environment.  When we went around corners the water would drip over the edge.  Not a big deal but these trays are not desinged to be on the move and the edge of the tray isn't enough to keep excess water from splashing.  Have a good drainage plan for the evaporators.

220v is what I had my units on.  Bad idea unless you are willing to pay premium prices and willing to go without when boondocking or staying with friends.  Sure you can run your generator 24/7 but you won't be able to use 30 amp or 20 amp hookups to run it.  And you wont have a redundant backup, so if your capacitor burns out or your brushes go out or your genny overheats it will be miserable on a 100 degree day.  No using an inverter or borrowing a 20 amp supply from someone.

Use 2 110v units.  If one goes out you'll have a backup.  And you'll be able to use a regular Edison 15 or 20 amp plug to run it.

Roof airs are noisy but cheap and easy to install and use. 

The best use for a window unit is taking it apart and creating a Mini-Split with it.  This is possible but you have to know what you are doing and have some HVAC know how.  I've seen one installation where the window unit was split up for drivers air.  It was a matter of extending some plumbing and adding freon. The compressor and exhaust fan was in the spare tire bay and 'hhe evaporator was in the drivers area above it.  The installer added a 12v fan with a switch for the evaporator unit.  Neat setup.

Other than that you don't want window units hanging out your coach driving down the road.

-Sean

[Seangie]

boondocking in a Prevost/GM/Eagle/MCI is like 4 wheeling in a Bentley...

Don -  Have you ever been 4 wheeling in a Bentley?


We boondock in our Eagle all the time.  Not backroad dirt and desert but wallyworld and city streets for sure.

[thomasinnv]

Majority of our time is spent boondocking. Almost never parked on pavement, and almost never hooked to a pole. But thats what I built it for, to be used.

[chessie4905]

 We had two 4104's in our family. One had 2 13,500 roof airs and the other had the same setup as yours with ducting. Both were at the same FMCA convention in summer. Came back to the coaches after sitting all day in sun with no hookups. Started generators and turned on AC's. Roof ac coach was comfortable in 1/2 hour or less. The other one was more than 1 1/2 hour to get as cool. That was the last trip with them. Changed to roof airs and never looked back. Also freed up bay space. Both ac systems were less than three years old. Ducted systems available today work pretty nice, but space is at a premium in the older 35 foot coaches. How well are those mini splits going to handle the pounding and vibration out on the road?

[andyps]

After installing mini-splits and running the gammit with those, Here's my 2 cents -

Mini splits are awesome when they work.  You really need to spend time and money on the install.  Number one issue is getting enough air to cool the external compressor unit.  It puts off a lot of heat.  Tikvah (Dave) has a single 9k unit and has to leave his bay door opened when parked.  When I had mini splits I had a hole cut into my bay door and floor of the bay with a fan forcing air down out of the bay.  I had a 24k unit and when driving it was barely enough to keep the external unit from overheating.  When parked the bay door was open.

So a cooling solution for the outdoor unit is needed.

Second -  the inside unit will collect water in a humid environment.  When we went around corners the water would drip over the edge.  Not a big deal but these trays are not desinged to be on the move and the edge of the tray isn't enough to keep excess water from splashing.  Have a good drainage plan for the evaporators.

220v is what I had my units on.  Bad idea unless you are willing to pay premium prices and willing to go without when boondocking or staying with friends.  Sure you can run your generator 24/7 but you won't be able to use 30 amp or 20 amp hookups to run it.  And you wont have a redundant backup, so if your capacitor burns out or your brushes go out or your genny overheats it will be miserable on a 100 degree day.  No using an inverter or borrowing a 20 amp supply from someone.

Use 2 110v units.  If one goes out you'll have a backup.  And you'll be able to use a regular Edison 15 or 20 amp plug to run it.

Roof airs are noisy but cheap and easy to install and use. 

The best use for a window unit is taking it apart and creating a Mini-Split with it.  This is possible but you have to know what you are doing and have some HVAC know how.  I've seen one installation where the window unit was split up for drivers air.  It was a matter of extending some plumbing and adding freon. The compressor and exhaust fan was in the spare tire bay and 'hhe evaporator was in the drivers area above it.  The installer added a 12v fan with a switch for the evaporator unit.  Neat setup.

Other than that you don't want window units hanging out your coach driving down the road.

-Sean

For the outside unit install, I was planning on ducting it from the bay door vents to the unit and then from there out under the bus. In the exhaust duct I wanted to use either a heavy duty, high cfm duct fan or some raditor type fans. Would that be sufficient?

If I go mini split, maybe I start with a dual zone 220v and then in the future add a second 120v unit. It's hard for me to justify two 120v units when they are limited to 12000 BTU and take up a lot more bay space (2 outside units), when I can get one outside 220v unit to run 2 (or more) indoor units.

My biggest concern with the 120v units is I'm not sure that two 12000 BTU units are enough.

For the window units, I never thought I'd run them out a window. I was thinking of a nice install in the bay of the bus or where my current evaporators are in the bus (in cabinets). Then running ducts/vents for all the hot and cold intakes and exhausts. Basically converting them to central units. A lot of work, but I've seen it done.

So you're no longer using mini splits? You converted to roof airs? Would you change your mind if you were only taking 3-4 trips a year (1-2k miles each) and keeping it in one spot for usage the rest of the time?

Thanks for all your insight!

[andyps]

We had two 4104's in our family. One had 2 13,500 roof airs and the other had the same setup as yours with ducting. Both were at the same FMCA convention in summer. Came back to the coaches after sitting all day in sun with no hookups. Started generators and turned on AC's. Roof ac coach was comfortable in 1/2 hour or less. The other one was more than 1 1/2 hour to get as cool. That was the last trip with them. Changed to roof airs and never looked back. Also freed up bay space. Both ac systems were less than three years old. Ducted systems available today work pretty nice, but space is at a premium in the older 35 foot coaches. How well are those mini splits going to handle the pounding and vibration out on the road?

Well my current setup is definitely not cutting it, which is why I'm looking at my options. I really don't want rooftops though. I don't want to cut holes int he roof, I don't like the look, and I didn't mention it before, but I'm 6'5" so our bus is already too short. I dont want to reduce any points in the ceiling if I can help it.

How the handle the road is a real test/concern I have too. Seems some people have lots of success with them on the road and others not as much.

Thanks for the thoughts!