I'm still wondering about using mini-split heat pumps in my bus. I believe two condenser units would fit in the original condenser bay. One evaporator over the driver's area and one mid-way back would work really nicely. I know some say that they are not durable enough for the vibrations, etc. of a vehicle. I'll accept those comments. What I'm wondering is how difficult they are to install. Some of them say that the lines are precharged and only require the connection of two freon lines. Am I missing something? Do they not need to be evacuated with a vacuum pump prior to charging, or are they pre-evacuated and closed off with valves? I'm also thinking about using one in my house, so if they are that easy to install, I'd certainly use the one at home first as the guinea pig. So, who has experience installing mini-splits, either in a vehicle or a building? Thanks for any feedback or comments.
David
Dave I do not have any experience installing them. If I were doing it again I would definately use the mini splits. 3 small units I think would be ideal.Not sure but I belive one condensor unit could be fitted in the area of the front axle
I have not used the mini splits but I did install a heat pump in my shop last year and the unit came precharged and all I had to do is evacuate the lines and indoor coil before turning on the valves to the outside unit. I had installed a unit in my house years ago that had the precharged lines and it was really simple to hookup. This is an idea that has promise over those rooftop units. Jerry
Go to www.dometictruck.com and pull up truck air conditioning. These are 11,000btu and 14,000btu units designed for the riggers of over the road trucks. They have two types-one that is a typical basement unit that is all in one where you have to cut two holes about 3x6" each for air supply, then duct the cold air. Then is the split system where the condenser with fan is outside and the evaporator/compressor unit is indoors connected by just the freon lines. The advantage to this unit is the outside condenser is smaller than a compressor unit (like from a household split system), and the evaporator/compressor mounts inside, typically at the base of a cabinet with a simple duct up to the top to have the cold discharge at the highest point.
Seriously look at these units since they are made for the trucking industry and can take the vibrations set up with road travel-compared to a household unit that is not reinforced for such travel. Cost wise, they are very close together. The split unit is what I would use in my next conversion project. I didn't use it now since I have a transit with limited under floor space. Good Luck, TomC
I looked at mini-splits, but I couldn't see how to possibly fit three of the condensers in a bus without sacrificing a lot of bay space.
The precharged linesets are nice, but they are usually pretty long so you might have a lot of excess line to deal wth.
Tom C, where can one buy the Dometic units and what do they cost? Looks like they could be a good way to go.
Thanks,
Don 4107
You might try Camping World, and I think the split system is around $2000. Good Luck, TomC
Hi David,
Just from, been there done that, you need 3 mini splits in a 40 ft bus. Thoose 12,000 btu units that are 115v seem to be a little undersized in
their ratings...??..?? I have 2 customers that can tell you that now. Daniel Odio, and Dave Schmidtt.. Both ended up having us install a 3rd mini split.
By far, theese mini splits cretinly take up alot of room under the bus too. Just their configuration of the connections and the air flo makes you
realize that they were not designed for mobile use in compact spaces.
Here is a pic of my design that has proven now to work super well, Bruce Knee now also has the same design as my coach.
They are 2 self contained 15,000btu heat pumps made by Dometic. We both added a hydronic heat coil in the return box powered by a Proheat as a redundent system.
Good Luck
Nick-
Quote from: belfert on May 04, 2007, 08:46:54 AM
I looked at mini-splits, but I couldn't see how to possibly fit three of the condensers in a bus without sacrificing a lot of bay space.
The precharged linesets are nice, but they are usually pretty long so you might have a lot of excess line to deal wth.
Yes, quoting myself here
I believe the mini-splits most of the posters have been talking about are the ones designed for home use with the evaporator in the bus and the condenser down below. The ones Nick is talking about are Cruise-Airs. I think the Cruise-Airs are really package units and not mini-splits since the evap and the condenser are both down below.
I have 3 cruise-airs in my bus and they are split units i guess they are made both ways
Quote from: belfert on May 04, 2007, 04:41:44 PM
Quote from: belfert on May 04, 2007, 08:46:54 AM
I looked at mini-splits, but I couldn't see how to possibly fit three of the condensers in a bus without sacrificing a lot of bay space.
The precharged linesets are nice, but they are usually pretty long so you might have a lot of excess line to deal wth.
Yes, quoting myself here
I believe the mini-splits most of the posters have been talking about are the ones designed for home use with the evaporator in the bus and the condenser down below. The ones Nick is talking about are Cruise-Airs. I think the Cruise-Airs are really package units and not mini-splits since the evap and the condenser are both down below.
Brian,
You are correct. The cruiseair's are called "self contained" or package unit.. The good thing about them is if either goes bad, just pull one out very
easily and replace it by my self. About an hour would complete it.
Nick-
Dave
IF THIS HELPS WE HAVE TWO MINI-SPLITS (HEAT/PUMPS).we are very happy with these .We live in southern Indiana with high humidity . Both units are 12,000 btu s. The only thing I set up differently was my aux heat is ducted into the bay with the condensing units, the aux stat. is set at 45* F. I was got these units from united refrigeration 3 yrs ago. The price was less than $900. for each unit(the prices have gone up around 30%) still very happy with this set up.
Dwayne Mc8 Tintent
I realize that mini-split A/C's aren't designed for a bus. I would use a standard basement unit, but I don't have a raised roof and know that running ductwork to the driver's area, in particular, would be a real pain. Where does one find the split Cruise-Air units? They'd certainly look better than the mini-splits.
David
www.dometicusa.com
Hi David,
Here are pics of the self contained and split systems that Tom Referred you to.
Nick-
David, i have 2 condensers in the spare tire compartment of my Eagle and one in the rear i had trouble with the 1 by the engine till i built a box to keep the heat away from it i have 2 small evaporators in the bed room i large 1 in the living room and 1 large over the ref in the kitchen the evaporators come in all different shapes and size i love the adjustable fan speeds but not the price of the units maybe Nick can save you some money i had to get mine from a marine dealer in Texas about 6 grand for 3 complete units
Caution important thing to unknowledgeable ....Split System is Always contain a pair of lines between unit.....that is NOT called self-contain unit....Like it read "Split System". Otherwise self-contain unit have ducting system which is NOT Split-System.
About either (non RV) residential & commercial unit can be design into larger or heavy vehicle type if you add isolators or insulators between loose tubing inside of compressor unit with tie-wrap and stronger grade mounting bolts & washers for compressor. You notice I quoted "heavy vehicle" not light vehicle that jars & very bumpy while traveling over pot holes with small diameter tires.
You can find Split System unit take-out for free if it came from school system been thorough damaging storm. Most of them are fine but being removed to rebuild school building with all new systems. Some of them are 110v/single/phase unit. I have many of them for free to install in a old (1926) 8 fireplace brick home and MCI-8.
Whatever you do, always keep high pressure smaller line hot from compressor until reach expansion valve or restricted line/hole via wrapping with good insulator...especially ex-long line of 10 ft or more. Need to maintain highest pressure as possible at evaporator point to get the maximum cooling differential effect. Another word hot high pressure will result lower pressure if cooled at the other end.
FWIW
Sojourn for Christ, Jerry
Quote from: Nick Badame Refrig. Co. on May 04, 2007, 02:11:05 PM
Hi David,
Just from, been there done that, you need 3 mini splits in a 40 ft bus. Thoose 12,000 btu units that are 115v seem to be a little undersized in
their ratings...??..?? I have 2 customers that can tell you that now. Daniel Odio, and Dave Schmidtt.. Both ended up having us install a 3rd mini split
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When putting in AC units we have to take into consideration the bus. Is it insulated? How much and what kind. Windows area, insulated or single pane. I have a 35 ft bus with the Saudi roof, spray foam insulation and large thermopane windows. There is also 1 1/2 in closed cell foam in the floor. The bus is painted ultra white, I chose this color, not becuse I like white but becuse it reflects heat!! A little common sense in a conversion goes a long way.
I have 2 13.5 K ducted roof top units, they are too big!! I have a 30 amp service so never run them both at the same time but if I did I could go into the frozen produce transport business.
When I said I would put 3 units in, i was thinking of 2 small units like maybe 6,000 BTU a
nd a 12,000 in the front.
In another method specified by one manufacturer, the compressor/condenser units are slightly overcharged and once the lines are hooked up, one specified fitting is cracked and the isolating valve opened for a set time to purge the air from the lines and then the fitting is tightened. Crude but seems to work OK.