Mini-split HVAC upgrade

[mshumer995]

I'm considering replacing the roof AC unit with a Mini-split HVAC.



To do it right, my thought is to remove the roof AC unit along with the sunroof forward and skin over both with new aluminum. The new interior mini-split would install on the ceiling with power and Freon lines routed down by sink, under the bed and out a port in the front.


The outside HVAC would mount behind the propane tanks where the battery is currently located.



I'm planning on replacing the lead acid battery with a sealed AGM setup under the dinette seat and route power along the floor under the bed back to the connectors by the hot water tank.


Any thoughts?

[Bubba L]

I’ve had a couple of friends install mini splits. Considered it myself. I would consider a few thoughts; how much distance required for air between back of condenser and front of trailer skin, secure mounting of the air handler inside considering movement and vibration while traveling, and some type of vinyl cover for the condenser on the tongue to keep road debris out of the coils. Good luck

[kidjedi]

Others have done it, and I plan on doing it in the future, but I haven't started researching which units are best yet. These splits aren't made with road vibration in mind, so durability is a concern. I think it's best to keep the internal unit and the outside condenser as close to one another as possible (keeping the line set short), so that should also inform the install. I do think the tongue is the best place for the condenser. I am considering building ducts with internal 12v fans to move air around better inside the trailer. A lot of these splits also incorporate a heater, so that's something to think about as well. Finally, someone posted this morning a link to "Cruise n Comfort" which I hadn't seen before. It looks like it's basically a split but designed for marine and road, and also apparently runs on battery power, so perhaps worth looking into?

[TG Twinkie]

The Cruise unit is $5,500. Way out of my price range.

[TouringDan]

Originally Posted by mshumer995

I'm considering replacing the roof AC unit with a Mini-split HVAC.



To do it right, my thought is to remove the roof AC unit along with the sunroof forward and skin over both with new aluminum. The new interior mini-split would install on the ceiling with power and Freon lines routed down by sink, under the bed and out a port in the front.


The outside HVAC would mount behind the propane tanks where the battery is currently located.



I'm planning on replacing the lead acid battery with a sealed AGM setup under the dinette seat and route power along the floor under the bed back to the connectors by the hot water tank.


Any thoughts?

There is a good thread titled “Split Air Conditioner Install” in the Interior Restoration Section.

I will be installing a Cooper Hunter 12,000 btu/hr unit in my 95 34’. It will be very quiet, very efficient (SEER is 21.5) and I believe will cool and heat the Airstream adequately.

Dan

[TouringDan]

Sorry, I couldn’t get this to load in the previous post.

[TouringDan]

Originally Posted by mshumer995

I'm considering replacing the roof AC unit with a Mini-split HVAC.



To do it right, my thought is to remove the roof AC unit along with the sunroof forward and skin over both with new aluminum. The new interior mini-split would install on the ceiling with power and Freon lines routed down by sink, under the bed and out a port in the front.


The outside HVAC would mount behind the propane tanks where the battery is currently located.



I'm planning on replacing the lead acid battery with a sealed AGM setup under the dinette seat and route power along the floor under the bed back to the connectors by the hot water tank.


Any thoughts?

How much ceiling room will the air handler require? I am thinking that it will reduce the head room quite a bit. I believe one of the biggest challenges in retrofitting a mini-split is where to install the air handler.

Dan

[Bubba L]

Dan, my wife and I revisited our thoughts on where to place the air handler when we considered installing a mini split in the 55. There is virtually no head room under a unit. I was going to rebuild two of the head lockers above the street side countertop and place the AH in those. We would have had doors to slide open (as original) and open them to allow the unit to distribute air. We didn’t go with a MS but a Dometic Turbo Blizzard instead. Wish I had gone with the MS. We thought about a street side compartment with a slide out compressor using flexible hoses. Maybe next reno.

[kidjedi]

Originally Posted by TG Twinkie

The Cruise unit is $5,500. Way out of my price range.

Yowch. Was not aware. Mine too!

[kidjedi]

Originally Posted by TouringDan

How much ceiling room will the air handler require? I am thinking that it will reduce the head room quite a bit. I believe one of the biggest challenges in retrofitting a mini-split is where to install the air handler.

I think the ceiling is out of the question. It seems the place that makes the most sense is in either end cap (rear bedroom with the condenser on the bumper (be careful about weight, you would likely need to build a reinforced "stand" for the condenser) or over a front dinette where Airstreams usually have a front cabinet. You could also do under a front dinette bench, but I think you would need to give consideration to active ducting (ducts with internal fans). I worry about running a long line set from mid-ship to the tongue. It could work, but it's more opportunity for something to go wrong. For something in the 30-34' range, I think a split in both end caps would be ideal.


EDIT: Wow. The Cooper and Hunter unit posted above comes with a 25' line set? I guess the technology has changed a bit since last I did my "in-depth" research.

[TouringDan]

Originally Posted by Bubba L

I’ve had a couple of friends install mini splits. Considered it myself. I would consider a few thoughts; how much distance required for air between back of condenser and front of trailer skin, secure mounting of the air handler inside considering movement and vibration while traveling, and some type of vinyl cover for the condenser on the tongue to keep road debris out of the coils. Good luck

Bubba

The installation manual recommends 12” behind the compressor. I am going to install mine right behind the jack and then go with a 10 or 20 Lb horizontal propane tank between the compressor and the trailer. I also plan on installing a vinyl cover over the compressor to protect it and maybe it will look better than the cream colored unit.

I am fortunate in the 34’ having some vacant wall space to install the air handler.

Dan

[TouringDan]

Originally Posted by kidjedi

I think the ceiling is out of the question. It seems the place that makes the most sense is in either end cap (rear bedroom with the condenser on the bumper (be careful about weight, you would likely need to build a reinforced "stand" for the condenser) or over a front dinette where Airstreams usually have a front cabinet. You could also do under a front dinette bench, but I think you would need to give consideration to active ducting (ducts with internal fans). I worry about running a long line set from mid-ship to the tongue. It could work, but it's more opportunity for something to go wrong. For something in the 30-34' range, I think a split in both end caps would be ideal.


EDIT: Wow. The Cooper and Hunter unit posted above comes with a 25' line set? I guess the technology has changed a bit since last I did my "in-depth" research.

The line set length is a bit confusing. It is 16ft although longer sizes are available. 16ft will be adequate for me I believe.

I believe I will be fine with just one unit in front. We don’t need to cool the bedroom during the day and with the reduced load at night the one unit in front should be able to cool the entire trailer.

Dan

[truckasaurus]

Hey Dan, I'm not looking at the same brand you purchased but all of the ones I'm keen on also said 12" minimum as standard but in the manuals had alternative minimums down to 4" albeit with a 10% performance reduction. My twisted logic is that a trailer tongue has way more air movement potential than being tucked into the typical floor wall nook so it'll probably balance out, maybe...

page 16 https://www.ecomfort.com/manuals/724...8ec82e60a5.pdf

[Iansk]

12" minimum clearance is for when the condenser is on a pad. Goes down to 4" min when hung on a wall, likely because you gain the added air direction (from down). It seems that a trailer tongue falls in the category of being hung on a wall... sort of.

Keep in mind that there is also a minimum clearance for the front so the exhaust fan isn't impeded. A pair of cylinders would block the exhaust pretty effectively.

Ian

[TouringDan]

Originally Posted by Bubba L

Dan, my wife and I revisited our thoughts on where to place the air handler when we considered installing a mini split in the 55. There is virtually no head room under a unit. I was going to rebuild two of the head lockers above the street side countertop and place the AH in those. We would have had doors to slide open (as original) and open them to allow the unit to distribute air. We didn’t go with a MS but a Dometic Turbo Blizzard instead. Wish I had gone with the MS. We thought about a street side compartment with a slide out compressor using flexible hoses. Maybe next reno.

Bubba

I thought just a bit about installing a mini-split in our Tradewind but there was no good location for an air handler. Besides, about 90% of our camping is in cooler weather where we don’t need A/C. Our 5k window unit works fine for us when we need it.

Dan

[Glenritas]

We have a ‘69 Trade Wind 25’ with front living room rear bath.
I installed a Coleman Mach 8 in the center of the trailer,it’s a 16,000 btu unit.
It blows front and rear . It cools the whole trailer very well up up to 90* . Above that I close the bathroom door and adjust the rear vent to reduce its flow and increase the front flow .

Bear in mind this is in the west with low humidity.
Above 100* the unit has all it can do to keep it below 90* .
I could use more btu’s under these conditions.

If your trailer is larger you need duel a/c.

Remember the cool you feel is the result of air movement on your skin. So unless the air conditioning is blowing on you won’t feel comfortable at higher temperatures.

As for a mini split you would need duel evaporators ( picture frame style ) mounted on the ceiling above living areas to be comfortable with a minimum btu of 16 - 18000 .

[Glenritas]

Another thought on a mini split is wiring it .
Think a separate breaker and inlet box mounted on the tongue for the unit with a detachable power cord.

This would make the retro fit simpler if your trailer is a 30 amp unit and your not doing a major remodel.

[TouringDan]

Originally Posted by Glenritas

We have a ‘69 Trade Wind 25’ with front living room rear bath.
I installed a Coleman Mach 8 in the center of the trailer,it’s a 16,000 btu unit.
It blows front and rear . It cools the whole trailer very well up up to 90* . Above that I close the bathroom door and adjust the rear vent to reduce its flow and increase the front flow .

Bear in mind this is in the west with low humidity.
Above 100* the unit has all it can do to keep it below 90* .
I could use more btu’s under these conditions.

If your trailer is larger you need duel a/c.

Remember the cool you feel is the result of air movement on your skin. So unless the air conditioning is blowing on you won’t feel comfortable at higher temperatures.

As for a mini split you would need duel evaporators ( picture frame style ) mounted on the ceiling above living areas to be comfortable with a minimum btu of 16 - 18000 .

The maximum mini-split size for 120v is 12,000 btu/hr. Anything larger requires 240v. So we just have to deal with 12,000 btu/hr and make that work. I believe it will work just fine. Here’s how I will make it work in our 34’. Close off the bedroom during the day. Turn on the two Maxxair fans in their “ceiling fan mode” where they are just moving the inside air around. If it is still too warm then install insulated window coverings over the 3 large street side windows and over the two skylights. I believe this will do it, but talk is cheap. I will perform a test after the unit is installed and the temperature is 90 degrees outside.

Dan

[mshumer995]

I'm planning on removing the roof AC so that wiring circuit will be used for mini-Split

[albert]

Originally Posted by TouringDan

There is a good thread titled “Split Air Conditioner Install” in the Interior Restoration Section.

I will be installing a Cooper Hunter 12,000 btu/hr unit in my 95 34’. It will be very quiet, very efficient (SEER is 21.5) and I believe will cool and heat the Airstream adequately.

DanAttachment 365684

Hey dan, where do you plan to install your interior unit? Roof or side wall?