Anybody replaced A/C in a fully-ducted system?

[MSHappyCampers]

I have a new Dometic Penguin heat pump on the way and I'm trying to figure out how to install it. My coach has the central air duct that goes all the way from front to back, passing directly below each A/C unit. There is a short metal duct from the discharge on the A/C directly into the top of the duct. The duct appears to be solid across the opening and into the ceiling on each side.

I don't see how I can get the new unit in place on top and make the short discharge duct match up. That's gonna be like threading a needle in the dark! Has anyone ever done this that can tell me how to go about it? I really appreciate your help!

[TechWriter]

MSHappyCampers wrote:
I have a new Dometic Penguin heat pump on the way . . .

BTW, if this is a Penguin II, I think you'll like it a lot more than your old Penguin.

[MSHappyCampers]

Thanks for your comments! I just got off the phone with Monaco tech support. I tried to reach them yesterday but never did. I explained the problem of making the ducts line up. They said that it was a real PITA! They told me the horizontal duct running from front to back is just styrofoam with a foil coating. I am going to cut the duct completely into on each side of the opening, install the top unit, attach the discharge duct, then put the duct back in place and tape it back together with foil duct repair tape! They say this should work fine! :B

[jorbill2or]

As long as you are replacing the ac head unit ( no interior ceiling grate ) with the same model the plenum will match up. They are kinda universal that way. At least I assume ( my bad) as that was the way it was on the one I did with a friend some years ago.

[OhhWell]

All that routing you see there usually comes out with the AC. I would have to look at mine again but people talk about replacing the ACs all the time. If the output on the new one doesn't match up, you could hire an HVAC guy to make a custom plenum.

[MountainAir05]

as you stated, everything from the top, remove the shroud, then mark all wiring and disconnect. Should be power 110v. 12 volt, and a telephone cable. Reverse step to install. Mine has four bolts which were under sealant. Lift off and clean, put in new gaskets and tighten equal. Had no issues setting back into the duct. Check you thermostat, The old ones will not work with the new Air Conditions. I sure many others will ring in with steps that I have missed.