Dual A/C's, but only 1 duct line

[Cocky_Camper]

Friday, I run the generator to exercise it and ran the A/C's. When I was running just the front one, I noticed the air was barely coming out the rear ducts also, then vice versa when I ran just the rear unit. I stuck a flashlight in one of vents and discovered that what I observed was true.

Is it common to have dual A/C's and for them to be connected to one set of duct lines? In the hot and humid summers in the south, the front seems to get a little warmer at times, especially with kids opening the door every 10 minutes. Would it be okay if I was to place some duct tape in the ducts to separate the ducts for each unit? If I keep all the front a/c air blowing in the front of the coach, I figured that may help more.

Thanks!

[T18skyguy]

Same in my 2017 Greyhawk. Turning on the second AC just doubles the output volume in the single duct. But it doesn't do it exactly evenly. With a single AC, there is more resistance to flow the longer the duct is toward the non running AC. It's much the same in forced air heat/AC in our stick houses. The room farthest from the AC/Heat fan get's the least volume.

[Fulltimers]

We like to run the front air when sleeping. This way we get the air through the duct to the bedroom but less noise.

[wa8yxm]

Yes it is very common for both units to share the same ducts.

[down_home]

We have two heat pumps on one duct system. We have dual zone controls and if the front is we get some good low in the rear and vice versa. We have sliding vanes on the five vents to adjust the flow.
If you don't have adjustable vents it is easy to change them out, if you can find them. I'm sure some Dealers catalog has them.

[Cocky_Camper]

dougrainer wrote:
I have NEVER seen a Ducted RV have 2 separate ducts. When you have just 1 AC running, you can run the other AC on FAN only to get cool air to the AC not running. Except for this post, I have never had anyone notice or complain about the One Duct system in 25 years. Doug

I wasn't complaining, but just didn't know this was common. I assumed the the 2nd a/c may had been added later, but it guess not. I never really paid much attention, and assumed that it was completely separate duct systems. But, this does make sense to run one and run the other unit on fan if on a 30amp site.

[dodge_guy]

I’ve noticed this on other RV’s and expect it. I plan on running both when I have 50A service. And with mine the previous owner had a nice padded cover fabricated to replace the stock interior AC vent cover. This way you could have the AC on and not hear the drone of the AC above you!

[2manytoyz]

This is also a plus when you end up with only a 30A site, and can only run 1 A/C. Though not as effective, it does blow cold air throughout the entire coach.

[dougrainer]

I have NEVER seen a Ducted RV have 2 separate ducts. When you have just 1 AC running, you can run the other AC on FAN only to get cool air to the AC not running. Except for this post, I have never had anyone notice or complain about the One Duct system in 25 years. Doug

[10forty2]

Yep. And in fact, the "ducts" in my rig are actually plenum channels cut into the ceiling insulation and directed to the interior of the coach by the vent covers. Seems to work just fine for us.

[Cocky_Camper]

I did not realize that this is normal for RV's.

[FloridaRosebud]

Cocky_Camper wrote:
Friday, I run the generator to exercise it and ran the A/C's. When I was running just the front one, I noticed the air was barely coming out the rear ducts also, then vice versa when I ran just the rear unit. I stuck a flashlight in one of vents and discovered that what I observed was true.

Is it common to have dual A/C's and for them to be connected to one set of duct lines? In the hot and humid summers in the south, the front seems to get a little warmer at times, especially with kids opening the door every 10 minutes. Would it be okay if I was to place some duct tape in the ducts to separate the ducts for each unit? If I keep all the front a/c air blowing in the front of the coach, I figured that may help more.

Thanks!

Yep, ours is set up the same way - 2 A/C units, one duct system.

Al

[imgoin4it]

Depending how you are parked in relation to the sun, particularly the west sun, I would not try to block any duct. If it is hot enough for a need for air conditioning I’d just run both. If it is like ours when the thermostat is satisfied it will shut down the appropriate unit. If really hot our rear unit could cool the bed room way down and the front one, running continuously could not quite keep up. We turned the bed room way down it and used a 9inch fan on the floor of the bed room and circulated air from the back to living area. Any way I’d run both and set the thermostat at the desired temp and leave it alone.

[newman_fulltime]

Its a rv not a home they all run in the same duct work in a rv

[Cocky_Camper]

larry cad wrote:
We have the same situation in our 40'. We typically have only one AC on at a time. Night time we use the front one, and keep the front vents closed so it blows into the bedroom (quietly). Daytime we run the rear AC with the rear vents closed. Again, it is quiet in the front. Seems to work well for us. If it really gets warm, we can run both with what ever vents we need at the time.

90% of the time, we always run both A/C's at one time. Never knowing noticing only 1 set of ducts.