Mini split A/C system

Topic: Mini split A/C system (Read 4447 times) previous topic - next topic

Re: Mini split A/C system

Reply #25 – September 08, 2021, 09:14:45 am

That's a pretty optimal placement of the head unit. Yeah, the line installation sure must have been a real cherry. Will be looking forward to real life performance reports, those units typically produce way above their ratings, or old style AC is rated far optimistic.
I've put probably a dozen of these units in family property. My experience with Pioneer...better than MrCool, quieter and more durable and when I've needed parts Pioneer was easy to work with. Not to mention for the difference in cost you can buy a vac pump, flaring tools etc and have em for the future. Nice job!

Re: Mini split A/C system

Reply #26 – September 08, 2021, 09:35:44 am

I think that these newer units are pre charged .

Re: Mini split A/C system

Reply #27 – September 08, 2021, 10:22:50 am

Still have to evacuate the linesets and evaporator on most of them. Gas is precharged in condensing unit.

Re: Mini split A/C system

Reply #28 – September 08, 2021, 10:47:49 am

The DIY series from Mr. Cool have sealing quick disconnects on the line connections and have the lines pre-charged so there is no evacuation required. One of our former members used this to allow a temporary mini-split install that could be disassembled for travel. Of course now I can't seem to locate the thread.

Re: Mini split A/C system

Reply #29 – September 08, 2021, 10:49:24 am

Right . My MR cool has dry breaks . The Pioneer does not . Good point. Thanks,MM
I like over the door.
Maybe I can drop the cables straight down the wall and to the nose , through Top surface of the side boxes ?

I still have to remove the safe for room in the fender.
The nose will get the bedroom unit

Re: Mini split A/C system

Reply #30 – September 08, 2021, 12:07:10 pm

Do you think that the cables can exit the handler box straight out of the left end of the case?

Re: Mini split A/C system

Reply #31 – September 08, 2021, 01:18:14 pm

There is a knockout on the both sides, the manual says: Left hand side recommended for side exit. Left rear (though the wall) most recommended but less common. Right rear less recommended but most common. Right hand side not recommended unless absolutely needed. I ran the lines out the left side right into the cabinet. (Yes, there was some major pucker factor cutting holes in the woodwork.)

The install manual is available online as a download.

I didn't run the drain line with the refrigerant lines because it was slightly uphill into the inside of the cabinet.

I am really surprised some creative HVAC tech or manufacturer hasn't played mix and match with mini-split and RV AC parts to create a rooftop mount that matches the capabilities of a mini-split. It could be all one unit, but you put in the inverter drive compressor and super quiet fans I am sure it would find a market.

Re: Mini split A/C system

Reply #32 – September 08, 2021, 01:43:25 pm

Ive looked at that .
Some engineering issues; tipping the condenser/compressor unit. The limit would concern the oil travels.
Configuring how to drain the inside air handler. It would have to be mounted above the roof surface .
The solution may be to use part of the OE handler ,and piggy back the compressor bits to feed it.

Marry the OE inside to the new outside stuff . Should be doable as the OE units are rated 13000 or more btu and should handle the loading . Still would contend with noise.
Frankenstien the new blower into the handler also.?
edit; the Minis are quiet because the blower motor runs slow and blows across the entire coil . The fan blade itself is pretty long. In order to pas the BTU the smaller coil needs a higher velocity air flow and thus more noise and amps.

Re: Mini split A/C system

Reply #33 – September 08, 2021, 02:04:53 pm

Have y'all thought about removing the compressor from your rooftop and relocating it into the engine bay. Since most of you seem to want to run your roof AC's driving down the road splice in the compressor that's engine driven so you can use your rooftop units . once at your campsite close the solenoid valve and run them off electricity.

Re: Mini split A/C system

Reply #34 – September 08, 2021, 03:35:12 pm

2 different refrigerants entirely incompatible. The top unit has to have the compressor that came from the factory to work.

Re: Mini split A/C system

Reply #35 – September 08, 2021, 03:42:58 pm

Since your not using dash ac change refrigerants

Re: Mini split A/C system

Reply #36 – September 08, 2021, 03:47:52 pm

I thought you were trying to reduce the compressor noise and use your rooftop units rolling down the road over and out

Re: Mini split A/C system

Reply #37 – September 08, 2021, 06:23:53 pm

Mostly I just want a quiet and efficient AC system that might run off of the inverter.

Re: Mini split A/C system

Reply #38 – September 08, 2021, 06:50:19 pm

Quote from: Protech Racing – September 08, 2021, 06:23:53 pm

Mostly I just want a quiet and efficient AC system that might run off of the inverter.

Exactly. There are 30+ SEER mini splits available... That's 30 BTU per watt, probably four times more efficient than the standard rooftop unit.

Re: Mini split A/C system

Reply #39 – September 08, 2021, 07:08:16 pm

I should've read the whole post first sorry for the railing🎈

Re: Mini split A/C system

Reply #40 – September 10, 2021, 12:02:34 pm

https://www.homedepot.com/p/Pioneer-12-000-BTU-1-Ton-19-SEER-Ductless-Mini-Split-Air-Conditioner-Heat-Pump-Variable-Speed-DC-Inverter-System-110-120V-WYS012AMFI19RL-16/311474980 700$
The 12kand 9K units share about the same footprint and it appears that the watts only go up about 150 from the 9 to the 12 . based on the my prior experience, the 9K will almost cool the entire small 36 ft bus while the 12K should easily cover it. IT may need a small fan to cool the bedroom but we use a fan for the noise and air as it is ..
Looking like this one will fit and draw 1080 watts. There are a couple with the same specs but this one is cheaper and heavier by a few #s . Not sure why there are more than one in the same game from the same manufacturer. This is maybe the older design and only SEER 19 .
I am very close to the 16 ft line requirement when mounted above the door. Run the cables/drain into the first cabinet anddown next to the window( behind the drapes) into the storage boxes. The drain exits the box and the lines continue along the box ceiling to the wheel well mounted compressor unit. Right where the safe is now mounted MOL.

Re: Mini split A/C system

Reply #41 – September 10, 2021, 12:09:12 pm

Be sure and allow an additional amount for each bend, they eat up more than you might think. There are also available flexible lines which you could add for a couple more feet and probably not a bad idea for vibration mitigation at connection to condenser. I've had two failures with Pioneer, both 9K units, but 18K have been rock solid. In fairness these were mounted in direct salt air blast off the beach but still it seems the larger units are more durable.

Re: Mini split A/C system

Reply #42 – September 10, 2021, 06:11:46 pm

I originally ordered the 16' lines and then realized they were too short. I then got the 25' set, and ended up shortening them about 16" to about 23' 6".

Performance wise, currently it is 89 degrees outside here in KCMO, but to simulate hotter weather I have the thermostat set for 62 degrees. That should be similar to a 77 degree setting on a 104 degree day. The thermometers are reporting 63 at the dash and 68 in the bedroom. It feels like a meat locker. How would it do in the desert sun? That remains to be seen.

I am going to run it at 62 until midnight so I can capture a full 24 hours of use to find the average load. So far it is has used 6.14 Kilowatt hours in 16 hours and 51 minutes, or an average of about 364 watts per hour. The coach is now mostly shaded, but was in the sun until about 2:00 PM. It was only about 74 out at 6 AM, so it wouldn't have been working very hard then.

The Pioneer website shows the inside 12000 BTU unit as 31.57" wide, so it wouldn't fit where I put mine, that is why I went with the 9000 unit.

Re: Mini split A/C system

Reply #43 – September 11, 2021, 01:26:06 am

Okay, it finished its 24 hour run. The mini-split used a total of 8930 watthours in 24 hours, or an average of 372 watts per hour. I am not sure how meaningful the number is, the coach was sitting mostly shaded, nobody was in it, no regular life style heat sources such as refrigerators, toasters, coffee makers or anything adding heat to the mix. I wish the Kill O Watt meter could handle the roof units so I would have a point of comparison. Anyway, there it is.

Re: Mini split A/C system

Reply #44 – September 11, 2021, 01:09:00 pm

Mike, You scared me a little but I was sure that I measured a few times for fit. I have 34.5 in space over the door between the cabinets.

AC rough math. The 400 or under watts will easily run from the 2000W inverter . As well as from the engine alternator . Drawing about40- 60 amps on cruise and maybe 100 at full on cold. The Eco mode should stay well within alternator range IMHO . This is about 1/3 the draw of the overheads ,MOL and they will not run from the alternator very long. ,or at all.
In my case I added a GM one wire 100 amp wired directly to the house bats -- because I dont know how the Duvac works on my bus as well as I like added redundancy .
Edit, more rough math.. If the overheads are using 1400 wats and output 14000BTU. Thats an honest SEER 10. The BTU output is suspect IMHO .
The Minisp[lits are using 350 - 600 watts and output 9000 - 12000. Real SEER around 17 or a little more . Its clear that the mini 9000BTU are large BTU..
Replace the overheads with solar and maybe even use the wires from the AC.

Re: Mini split A/C system

Reply #45 – September 11, 2021, 06:28:48 pm

Well, I just did a bit more testing, running the mini-split off the inverter. Ran 4 hours, set at 74 degrees, outside temp was 91 when I started, 89 when I finished. The Kill O Watt reports 1.97 Kwh used, the Xantrex battery monitor reports 197.7 Amp Hours used (12 volt system). 51.1 % charge remaining on my pair of O'Reillys 8D AGMs. I did find online that the Kill O Watt meters tend to over state use on some loads.

This is working so well I am kind of thinking of taking off the old roof top units, at least the front one. That would free up more than the area of the unit itself as I was also not going to use the shaded area for solar as well. I could probably fit two more 250 watt solar panels. I have 7 waiting to go on, just haven't gotten around to it.

I just ran the monthly engine exercise, idle until air pressure comes up, then 15 minutes at 1200 rpm, then 2 minutes at idle again. The batteries were still down so it was a chance to see what the charging system could do. I was seeing 60-85 amps going into the batteries even while still running the mini-split. My coach has had the OE alternator replaced with a 160 Amp Delco unit.

Re: Mini split A/C system

Reply #46 – September 12, 2021, 01:15:20 am

Has anyone considered a mini-split, using a ceiling mounted evaporator, in place of the roof mounted AC unit?

Tim

Re: Mini split A/C system

Reply #47 – September 12, 2021, 01:27:04 am

I have been wondering if we are looking at this wrong. Maybe one of the concealed ceiling units in place of one of the propane furnaces, or maybe under the refrigerator? I kept looking at the ceiling cassette type, but they are 22.5" square and too thick for an RV ceiling, but I forgot the concealed units.

Re: Mini split A/C system

Reply #48 – September 12, 2021, 12:28:05 pm

Quote from: TGordon – September 12, 2021, 01:15:20 am

Has anyone considered a mini-split, using a ceiling mounted evaporator, in place of the roof mounted AC unit?

Tim

yes
Looked at this. You have to run the lines down through the wall to the compressor unit.
The concealed wall would work in place of the front heater but that dumps at the floor.

Re: Mini split A/C system

Reply #49 – September 12, 2021, 04:48:03 pm

I was thinking about running the lines through the engine room and roof, for the rear unit, and through the refrigerator compartment and roof, for the front unit.

Tim

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