2020 Flying Cloud 2 ACs Behavior Question

[DanHogHunter]

Our FC has two air conditioners with "2 zones" and have found the way it works to be a bit odd and, therefore, have wondered if it is the expected behavior. It seems that no matter what AC is running, air is blowing out all the vents with most of the air going to the RB area. This means that the RB area cools down first. The other night the difference between the RB area and front lounge ended up being very significant. It was 76 up front and 64 in the back.
With two zones, I expected the air to stop blowing in the back when it reached the desired temperature, but that did not happen, although the Zone 1 AC did turn off.

[Philip Jones]

The ducts throughout are attached therefore there is no discrete zone 1 and 2. Whatever flow is generated is dictated by the vents being open or closed. So, you could play with the flow to either area by opening or closing vents selectively. (BTW Zone 1 is the zone for the main thermostat.)

In our 27 FB, the thermistor for zone 2 (dinette/kitchen) is behind the TV. This zone is therefore always a few degrees "warmer" even when all windows are open and no AC is on. Therefore, to achieve equal temperatures, we find that we have to set zone 2 a couple of degrees warmer than zone 1.

Confusing.

[Mollysdad]

Originally Posted by DanHogHunter

Our FC has two air conditioners with "2 zones" and have found the way it works to be a bit odd and, therefore, have wondered if it is the expected behavior. It seems that no matter what AC is running, air is blowing out all the vents with most of the air going to the RB area.

The ducts are all one long tube. So some air from zone one will blow out of zone two. I find that just because of the longer distance more air from zone one will stay in zone one.
You could experiment by closing off some of the zone two vents.
If I run both ac's, to cool faster, I set the temperature slightly different. That stops both ac's from cycling on and off together.
At night to reduce noise, I'll run only zone one (living area) but still get some air in the bedroom.
Keep in mind, the thermostat is in zone one (at least on mine) and so it may be cooler there. Also if you set to 74f. it may cut on at 77f. and off at 72f. Usually, just about the time I think it's not coming on, it does.
What you wrote doesn't all match, so although you will get air in zone two from ac 1, it shouldn't be colder than zone one.
The fact that air is getting between zones makes me think there's no obstructions in the ducts.

[BayouBiker]

In addition to the common duct work as described, blown air back flows out the air intake on the unit that is off further distributing conditioned air to the unintended zone. Other than adjusting the vent dampers and offsetting the temperature settings (as others described) to get better balance I have yet to come up with any good ideas.

Continually running the fans is not a great solution especially while in a humid area works poorly because the airflow across the water pan and communication to the outside due to the overflow drain excessively raises the humidity inside the trailer.

Would love to hear some other ideas.

[DanHogHunter]

Originally Posted by Mollysdad

The ducts are all one long tube. So some air from zone one will blow out of zone two. I find that just because of the longer distance more air from zone one will stay in zone one.
You could experiment by closing off some of the zone two vents.
If I run both ac's, to cool faster, I set the temperature slightly different. That stops both ac's from cycling on and off together.
At night to reduce noise, I'll run only zone one (living area) but still get some air in the bedroom.
Keep in mind, the thermostat is in zone one (at least on mine) and so it may be cooler there. Also if you set to 74f. it may cut on at 77f. and off at 72f. Usually, just about the time I think it's not coming on, it does.
What you wrote doesn't all match, so although you will get air in zone two from ac 1, it shouldn't be colder than zone one.
The fact that air is getting between zones makes me think there's no obstructions in the ducts.

We seem to be getting more air in zone one (the bedroom in our trailer) no matter which air conditioner is running.


I plan to slightly close off the bedroom vents to see if I can balance the air flow a bit.


Thanks, the information that there is only one duct reassures me that there's not a problem with that part of the air conditioner.

[DanHogHunter]

Originally Posted by BayouBiker

In addition to the common duct work as described, blown air back flows out the air intake on the unit that is off further distributing conditioned air to the unintended zone. Other than adjusting the vent dampers and offsetting the temperature settings (as others described) to get better balance I have yet to come up with any good ideas.

Continually running the fans is not a great solution especially while in a humid area works poorly because the airflow across the water pan and communication to the outside due to the overflow drain excessively raises the humidity inside the trailer.

Would love to hear some other ideas.

I was aware of the humidity problem when running the fan continuously (thanks Dad ). I will try adjusting the vent dampers.

[DCPAS]

Originally Posted by Mollysdad

If I run both ac's, to cool faster, I set the temperature slightly different. That stops both ac's from cycling on and off together.

I thought I read somewhere that the thermostat keeps the A/C's from starting at the same time.

[pteck]

I find a small 12V Cigarette lighter / USB fan aimed down the hallway does wonders to balance the temperatures in the Airstream. Suction cups to the ceiling so easy to setup and remove.

[5150mike]

This may have been coved, but if on 30amp and running one AC, would it be beneficial to run just the fan on the other AC ? This is something I have not tried, but I will this weekend

[BayouBiker]

Originally Posted by 5150mike

This may have been coved, but if on 30amp and running one AC, would it be beneficial to run just the fan on the other AC ? This is something I have not tried, but I will this weekend

It distributes the heat and cold nicely but if it's humid, it pulls in moisture from the evaporator drip pan and outside overflow. The humidity will rise to nearly match that of the outside down south in the summer its not a good option.

[DanHogHunter]

Originally Posted by pteck

I find a small 12V Cigarette lighter / USB fan aimed down the hallway does wonders to balance the temperatures in the Airstream. Suction cups to the ceiling so easy to setup and remove.

Attachment 374932

I like this idea!!! Can you point to a fan that you are using?

[pteck]

Happy to. I got this one on Amazon. There's lots of different varieties including USB and rechargeable ones.

https://www.amazon.com/Electric-Cool...b-8a79de2d236f

[oldwagon]

Hi All
We have the FC 2020 28ft model! On 30 amp can only run just One unit! On 50 amp could run Both units! Having the Two units! Maybe in Hotter country the second might come in handy? And no matter where we travel we use our electric power unit to avoid high electric surges!
We like just running One unit suits us fine so far! The bedroom gets cooler so i close a vent! Other then that perfect for us it was hot and high humidity in June and it was perfect inside our Cloud! See you down the road, safe travels!

[DCPAS]

Originally Posted by oldwagon

On 30 amp can only run just One unit! On 50 amp could run Both units!

Being in way too hot parts of Texas and having state parks with with 30 amp service max, I put Easy Starts on both A/C's. That allows us to run both A/C's, but you do have to be careful with power management. Run the water heater and fridge on gas, for example and you need to turn an A/C off if you want to run the microwave. Expensive to add two Easy Starts, but I would do it again in a heartbeat.

[5150mike]

Originally Posted by BayouBiker

It distributes the heat and cold nicely but if it's humid, it pulls in moisture from the evaporator drip pan and outside overflow. The humidity will rise to nearly match that of the outside down south in the summer its not a good option.

I did confirm this this weekend when running zone 2 (living room) with fan set to low when the compressor would go off and fan keeps running of course, well the humidity would go extremely high, but after getting the fan to auto it brought the humidity down,

[Mollysdad]

A 120v fan is a good idea. It helps move the air evenly throughout the trailer.
I have this one. It can hang on a wall or sit on a counter.
Amazon $20.
I also have a clip fan that is powered by the USB port. Super quiet. I have it on the magazine rack by the bed.