Dometic AC Duct (2022 EII)

[Steve and MA]

 

 

This weekend I thought I’d peek inside the Dometic AC ceiling distribution box in my 2022 EII with the idea of looking for a way to quiet it down.  I did line it with Noico 80 mil butyl mat.  Noise was only reduced by 1-2 dB, so hardly worth the effort, and any improvement by the mat is difficult to assess because of another issue that I corrected.

After removing the distribution box, I found that the duct between the fan and the box wasn’t connected.  The duct is a mylar tube wrapped with a wire coil.  It’s supposed to be attached at the top with a zip tie around the flange by the fan.  It's held in place by a grate at the bottom.  In my case, the zip tie and duct were not completely wrapped around the flange.  

Though plenty of air seemed to be coming out of the five vents of the box, the gap was large enough that a good portion of the cold air must also have been redirected right back into the intake.  It’s not easy working in the tight space, but I was able to reattach the duct.  Hopefully it will remain connected. If you think you’re not getting enough air volume from the vents, then this may be worth looking at.  I imagine this could affect the frequency that the compressor cycles, and possibly cause the evaporator to freeze over, but I hadn’t had these issues. 

I’ve attached pictures of the disconnected duct, as well as a picture from Dometic showing the locations of the eight screws that hold the box to the ceiling.  The zip tie in the pictures is exactly like I found it.

Steve

[Rivernerd]

Are Dometic Penguin II's made in the USA?

[Steve and MA]

Ours was made (assembled) in Mexico.  The duct is connected between the inner and outer pieces of the AC.  It's connected by the installer, not the Dometic factory.  However, I wouldn't be quick to blame the Oliver installation.  Before disassembly I had been taking measurements of the noise levels, including with all vents closed.  This could have caused the duct to be blown off the flange. 

[John Dehne]

Thanks for the info, I will check Hull# 901, Safe Travels.

[Trainman]

I would like to see RV A/C units built like the home/business Ductless units. We have one in my wife's Woman Cave and it's quite, you could mount the outside compressor unit either upfront, or in the rear, sure might take a little rearranging of things. Both the heat and A/C outputs are high and super quite. 

trainman

[John E Davies]

That is unfortunate. I am not convinced that a nylon cable tie, even a big one, makes for a proper HVAC clamp, it really needs a worm screw steel one, IMHO. Once positioned and tightened correctly, it should not “blow off”. Cable ties are used in residential duct installations, but they usually just support the weight from a rafter, the actual connections are first screwed and then either taped or puttied.

Thanks for posting the pictures.

John Davies

Spokane WA

[John E Davies]

49 minutes ago, Trainman said:

I would like to see RV A/C units built like the home/business Ductless units. We have one in my wife's Woman Cave and it's quite, you could mount the outside compressor unit either upfront, or in the rear, sure might take a little rearranging of things. Both the heat and A/C outputs are high and super quite. 

trainman

Me too 😬 I was just researching a little mini-split for my master bedroom. Here is one with a jaw dropping SEER (Seasonal Energy Efficiency Rating) rating of over 33. I don’t recall what my home Carrier AC unit is, maybe 14… these newest models have inverter controlled variable speed compressors that do not cycle on and off, they run at varying loads to keep the room temperature very close to the set temp.

https://hvacdirect.com/mitsubishi-mz-fh06na-6-000-btu-33-1-seer-ductless-mini-split-heat-pump8958.html

I think a 6000 btu model would work fine for an Ollie, since it could run constantly and efficiently without having to deal with the traditional on off cycling. These are all 240 volts, I am sure an RV model could be made for 120. Maybe the 2025 Ollies will use one.

Sorry for the thread highjack.

John Davies

Spokane WA

[SeaDawg]

Mr cool makes at least one 12000 btu 120v system. (We have a larger one in our garage.)

The problem is, where to put the condenser? And, the interior unit is quite large, as well. Even if it fit, it would take up the entire attic space.

Bonus if you figure it out. 22 seer. Extremely quiet. Well constructed.  Coastal rated fins on condenser. Quiet night mode. Our smaller unit, in the garage, was diy. Charged line comes with the units. We looped up the extra.