Atwood 15K A/c unit

Topic: Atwood 15K A/c unit (Read 3116 times) previous topic - next topic

Re: Atwood 15K A/c unit

Reply #50 – August 22, 2019, 01:45:48 am

I would not consider this as a reliable source, do your homework well in regards to the voltage and hertz. Extraordinary claims require extraordinary eveidence. Physics are physics, and you simply cannot tweak or supertune a RV a/c units in it's current form factor/size.

Re: Atwood 15K A/c unit

Reply #51 – August 22, 2019, 09:16:00 am

Quote from: Don & Tys – August 21, 2019, 03:40:20 pm

I much prefer the lowest possible profile...

Should form follow function? That is the question. Some want their roof air conditioners to be low, sleek, and as inconspicuous as possible.

Others want maximum efficiency - style be damned. Are the two disparate goals attainable in one single form factor?

As I understand it, you have to move lots of air through the condenser to effectively shed the heat being removed from inside the coach. When I look at the two roof unit "shell" designs in the photos below, I find it hard to believe that they can both allow the same volume of air flow through the condenser. I'm no expert, but...BIG hole versus small hole...right?

Each A/C buyer must decide what is most important to THEM, then buy the unit that comes closest to making them happy.

Re: Atwood 15K A/c unit

Reply #52 – August 22, 2019, 10:44:40 pm

In my view, form should follow function. I just don't don't know whether the traditional designs are anywhere close to optimized. I don't have any dogs in this hunt right now, so no incentive at this point to delve into it other than a superficial curiosity. I hope that is true for at least the near term because I have much on the project list that could represent quite a few coach bucks. That said, all of the unconditioned air as well as the conditioned air has to go through the same approx. 14"X14" hole in the roof. The Houghton Belaire 3400 A/C that I linked to is about 8 ¾" high (roughly the same as our current Dometic Penguins, if I am not mistaken), and about 44 ⅛" long by 34 ½" wide as compared to the Atwood's 39" long x 26-1/2" wide x 14-1/2" tall. So though the Atwood is almost 6" taller, it is shorter in length by 5" and narrower in width by 8". Still, even though from the function standpoint, the Atwood is likely superior to the Dometic Penguin, they won't be an option for long except maybe for new old stock if they can be found at all. If I was looking right now for a replacement, that wouldn't necessarily deter me. Heck I bought a NOS Atwood two stage furnace for our coach because I couldn't find a better option at the time we needed it. No warranty, no returns. So far, that has worked out. In the case of the furnace, pretty much all of the failure mode parts are still obtainable and I feel confident that I could fix it if necessary. From the video I watched, the Houghton Belaire has a more impressive build quality than what I saw on our Dometics when I changed the capacitors and replaced the covers on them. I don't doubt that the 25 year old design of the Dometics couldn't be improved on. I don't know nearly enough about the these Australian or European built units to gage whether they are the real deal, or whether the provenance of the 120VAC 60Hz conversion from the European/Australian 240VAC 50Hz is something I would trust, or even what the key elements of the engineering approach used in their design is. Maybe in a few years (if our OEM units last that long), I will look into and just maybe, they will have more of a presence in our US market. Or maybe their presence here will spur Dometic and the rest to raise their game... but not holding my breath. Likely Dometic would buy them out and kill their product like they did with Atwood's innovative Helium absorption fridge, their Excalibur XT two stage furnace, and now the Atwood A/C's.
Don

Quote from: Chuck & Jeannie – December 18, 1974, 08:19:30 pm

Should form follow function? That is the question. Some want their roof air conditioners to be low, sleek, and as inconspicuous as possible.

Others want maximum efficiency - style be damned. Are the two disparate goals attainable in one single form factor?

As I understand it, you have to move lots of air through the condenser to effectively shed the heat being removed from inside the coach. When I look at the two roof unit "shell" designs in the photos below, I find it hard to believe that they can both allow the same volume of air flow through the condenser. I'm no expert, but...BIG hole versus small hole...right?

Each A/C buyer must decide what is most important to THEM, then buy the unit that comes closest to making them happy.

Re: Atwood 15K A/c unit

Reply #53 – August 25, 2019, 01:52:04 pm

Here's a good article on HVAC motors: What you need to know about electric motors in HVAC systems
I'm going to try and squeeze a few more years from our original Penguins, in hopes that 120V inverter rooftop units, that I can easily run off the PV/ house batteries/inverter, are readily available when we're ready for (or forced into) an upgrade. It would be great to see a company with experience manufacturing inverter drive appliances (Samsung comes to mind) jump into the market. Produce one efficient model, en mass, to keep the pricing reasonable. Another area that needs attention on these rooftop unit is airflow management. Based on the units I've seen, the engineers really need to learn about laminar airflow, and apply it to their designs. On our Penguins, and Duo Therms on the SOB, the intake air has two major (an abrupt) changes in velocity between the grill and evaporator coil. The discharge side isn't much better. This not only creates additional noise, but is very inefficient.

Re: Atwood 15K A/c unit

Reply #54 – August 25, 2019, 02:35:48 pm

Greg,

I share your hopes for better design and technology in this area...someday.

I agree with Don (above) when he points out how the "conditioned" and "non-conditioned" air must be forced through the same 14" square hole, and how this compromises function. Why does every manufacturer keep building to this archaic mounting standard? Because no company wants to rock the boat? Why doesn't some company step up and say "We need to change the way we mount air conditioner components in/on RVs". Surely sticking a big box on the RV roof can't be the best idea we can come up with...

I personally wish, along with many on this Forum, for air conditioner units built more along the "ductless mini split" design. Once you separate the two halves of the system, your mounting options really increase. All we need is for the motorhome builders to provide a suitable location for the outside compressor/condenser module, so it wouldn't look "added on", and where air flow through the coils could be optimized. The inside evaporator/air handler modules would be easy (I would think) to incorporate into the existing interior layouts. One module could even take the place of the "automotive" dash air unit.

Then, if the inverter drive technology could be built into the outside compressor unit, we could run the whole shebang on (big) batteries!

However, until something better comes along, we're stuck with roof warts.

Re: Atwood 15K A/c unit

Reply #55 – August 25, 2019, 02:52:30 pm

One thing I noticed in our Attwoods is a duct work in the interior mounting plate that secures the roof unit on that smoothly changes the downward moving cool air to evenly split fore and aft horizontally moving air. So, some thought in that unit to directing air flow.

Re: Atwood 15K A/c unit

Reply #56 – August 25, 2019, 03:45:26 pm

The inside chunk of the minisplit still needs to shed the water somehow. Thats why I see it best mounted in the nose firewall, dripping on the ground , pushing air up my skirt.
Mounted overhead forces a drain engineering of some kind. The current method drains the unit onto the roof . We have accepted that as the norm .

Re: Atwood 15K A/c unit

Reply #57 – August 25, 2019, 03:56:00 pm

Just build vertical drain tubes into all the exterior walls. Space them out at 12"-16" intervals. The inside air handlers (mounted on the walls) would connect to the nearest tube - dump the water on the ground. EXCEPT IN KALIFORNIA!!!!

Re: Atwood 15K A/c unit

Reply #58 – August 25, 2019, 04:00:29 pm

It would be nice if we could use these mini splits with the ceiling register. We could put the ceiling register in the 14" opening and route the lines through the ceiling duct all the way to the back. Then we can mount the outdoor unit on the rear in place of the ladder. Nothing on the roof. Just make a cover for the roof top holes. Now to get the right power. Do we need to upgrade our electrical and generator? Our generator is capable of producing 240v with the correct regulator.
John M.

Pioneer® 12,000 BTU 21.5 SEER 8-Way Compact Cassette Mini-Split Air Co –...

Re: Atwood 15K A/c unit

Reply #59 – August 25, 2019, 04:15:13 pm

Problem with 208-220 volt units, can't use them if you only have 30 amp service at a campground.

Re: Atwood 15K A/c unit

Reply #60 – August 25, 2019, 11:01:00 pm

But these may work, just have to find a good place for the evaporator and condenser units.
Ductless Split Air Conditioning | Heating System | DC Inverter – Pioneer...

Re: Atwood 15K A/c unit

Reply #61 – August 26, 2019, 12:44:34 am

They can be built, and they can be efficient and somewhat less noisy. Pod size on the roof would have to increase. I don't think anybody would mind that. big ? Is would you pay even $1800 per unit. Samsung or LG are not interested in 10-15,000 units a year if that as IDK how big the rv market actually is.

Re: Atwood 15K A/c unit

Reply #62 – August 28, 2019, 09:47:57 am

Quote from: Hans&Marjet – August 12, 2019, 06:29:01 pm

Chuck, I did, they called me back today and offered a black covered unit.....not for us. They also mentioned once the stock (black units) are depleted there will be no more.

H

I ordered 2 units the other day from them. They said they were white. I asked specifically about it. But even if they are black, I will paint the covers and be happy with them. The next one up, the Coleman mach 15, is 900 plus and I need 2.

Re: Atwood 15K A/c unit

Reply #63 – August 28, 2019, 10:04:39 am

I have to say.. never expected the Atwood to be so quiet.. cant hardly hear it on high and the air it moves is unreal..

Re: Atwood 15K A/c unit

Reply #64 – August 28, 2019, 10:17:37 am

Quote from: Bob and Julie – August 28, 2019, 09:47:57 am

I ordered 2 units the other day from them. They said they were white. I asked specifically about it. But even if they are black, I will paint the covers and be happy with them. The next one up, the Coleman mach 15, is 900 plus and I need 2.

Strange....they said no white units anymore...I reordered the black units and received 1 from Goshen IN yesterday and the other is coming today from Dometic in TX

Re: Atwood 15K A/c unit

Reply #65 – August 28, 2019, 10:16:15 pm

Quote

Strange....they said no white units anymore...I reordered the black units and received 1

Pretty funny. I couldn't find a black one so my white one arrived yesterday and I will paint it black!
jor

Re: Atwood 15K A/c unit

Reply #66 – August 28, 2019, 10:37:54 pm

Quote from: DavidS – August 28, 2019, 10:04:39 am

I have to say.. never expected the Atwood to be so quiet.. cant hardly hear it on high and the air it moves is unreal..

Maybe due, in part, to what Rudy said: "One thing I noticed in our Attwoods is a duct work in the interior mounting plate that secures the roof unit on that smoothly changes the downward moving cool air to evenly split fore and aft horizontally moving air. So, some thought in that unit to directing air flow."

Re: Atwood 15K A/c unit

Reply #67 – August 29, 2019, 05:45:26 pm

Quote from: jor – August 28, 2019, 10:16:15 pm

Pretty funny. I couldn't find a black one so my white one arrived yesterday and I will paint it black!
jor

John should we switch black/white ? but i need 2 whites...you need 2 blacks ?

Re: Atwood 15K A/c unit

Reply #68 – August 30, 2019, 10:03:46 am

Quote from: Rudy – August 13, 2019, 12:40:43 pm

Frank, I will be very interested in your findings.

They also state the compressor has a soft start feature, no current spike (70 amp) and hard hum as the compressor starts.

I put a soft start on my Attwoods. You can not hear compressor start, instead of my clamp on amp meter reading nearly lock rotor current spike, it starts at 2 amps, then 6 and finally get to 14.

Thanks for giving one a go.

Hi Rudy,
Well I picked the coach up yesterday and the service manager did the walk through with me. I'm happy with the level of service at this Bellevue NE location and will be back for more service at their level.
The Furrion (non ducted), the interior functions of the Furrion are less than impressive. No remote thermostat, it's all on the bottom of the unit, analog dials, impossible to read at night or after a couple of drinks without turning on the lights and getting my glasses. Ok I couldn't read the old slide thermostat either but I knew left was more cold/right was less cold. What I do like is the soft start vs the old HAMMER start. It would seriously make the entire coach rock. The new unit is also MUCH quieter than the old unit while running and you can shut the airflow off to the rear side by shutting that vent. Shutting off the rear vent means the air isn't blowing in my face when I sleep and it forces more air forward into the hallway. Wasn't an option on the old unit. Inside footprint is smaller than the original so I now have to get the carpet cleaner out and scrub those areas. Maybe there are other model Furrions that have more options. It does seem to cool the air better and move more air than the old unit. This unit is in and paid for so we'll keep it. It is an improvement over the old unit, just not what I would have preferred in our rolling cabin. The unit we have would look better and be more at home in a travel trailer. True test comes in a few days when we hit the road for a couple of weeks.
Cheers!

Re: Atwood 15K A/c unit

Reply #69 – August 30, 2019, 10:43:49 am

Quote from: Phranko – August 30, 2019, 10:03:46 am

...you can shut the airflow off to the rear side by shutting that vent. Shutting off the rear vent means the air isn't blowing in my face when I sleep and it forces more air forward into the hallway. Wasn't an option on the old unit.

Thanks for the "early" review. Perhaps you can add to it after you get some more time playing with the unit in different conditions.

Being able to shut off the rear facing vent is a valuable feature. It is not available on the Atwood - I touched on this fact in my review of same. I found I was able to "get used" to the air blowing down on my head when sleeping, but would like the option to shut it off (DW does not mind it). Of course, a piece of duct tape would accomplish the same thing, but looks kinda tacky (ha, ha....get it....tape = tacky).

We also had to clean off a little of the ceiling "shadow" from the old units. Carpet cleaner took it right off the wooly Ozite material.

Re: Atwood 15K A/c unit

Reply #70 – August 30, 2019, 10:52:16 am

Ordered one of the easy starts to to on my front ac new attwood unit. Its hooked up via the inverter so that should work well. I might go with a 2nd one for the rear later on.

Re: Atwood 15K A/c unit

Reply #71 – August 30, 2019, 10:54:49 am

Quote from: Bob and Julie – August 30, 2019, 10:52:16 am

Ordered one of the easy starts to to on my front ac new attwood unit. Its hooked up via the inverter so that should work well. I might go with a 2nd one for the rear later on.

Take photos of the installation and post a report for those who follow. I have a EasyStart sitting on my bench but waiting for cooler weather.

Re: Atwood 15K A/c unit

Reply #72 – August 30, 2019, 11:59:22 am

Frank, Thanks a bunch for the report. All the best.

Re: Atwood 15K A/c unit

Reply #73 – August 30, 2019, 12:09:46 pm

When installing these 2 Atwood units will I need 12V power supply at the unit along with 110V ?

Thx

Hans

Re: Atwood 15K A/c unit

Reply #74 – August 30, 2019, 01:16:47 pm

Quote from: Hans&Marjet – August 30, 2019, 12:09:46 pm

When installing these 2 Atwood units will I need 12V power supply at the unit along with 110V ?

On our non-ducted Atwood units, the answer is NO - 12V power is not required. See Page 4 of manual:

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