Another AC Conundrum??

[avvidclif]

While researching options for a second AC unit for the bedroom of a CF305SK we are thinking of buying I found something that I can't explain.

I found the installation instructions for a Dometic 15k AC unit.
See http://www.dometic.com/1f24ead8-6316...87ce6bad.fodoc

They show a flow rate of 325CFM. The minimum duct size is to be 1.5-2.5x7-10 inches. I don't know how that compares to Crossroads setup (my unit is at the dealer for a repair) but the next point is interesting, a minimum of 4 registers required and up to 8. My unit has 4 registers, 3 in the living area and 1 in the bedroom. That meets the minimum spec.

But what happens when you tie in a second ac unit to the same ductwork? It seem to me you would be spinning your wheels unless one or both had the trap door (fast cool) open slightly. Just too much airflow for the existing ducts.

This was brought to my attention by looking at another brand of rv with a 15k ac unit. It had 7 ducts in the living area and 1 in the bedroom. It was designed and wired for a second ac unit but the dealer told me the second one would not tie into the duct system???? It would be a stand alone unit only cooling the bedroom. It would tie into the same thermostat but not into the duct.

Maybe that's why I have a hard time cooling my rv when the temp goes over 100. Plenty of ac capacity just no airflow.

Thoughts???

[Ramn4ver]

Here are my A/C post. For more air flow.first post
second post

A/C is working great now 23° cooler then outside.Edited by: Ramn4ver

[Hunter11]

Clif, our unit has 6 vents in the living/kitchen area, 1 in the bathroom and 2 in the bedroom. With a 15k main and 13.5k bedroom ducted units we get plenty of air flow. Now that is after I went in and fixed one of the ducts that Crossroads had not sealed the end on and was blowing cold air into the attic area and sealed all the vents at the ceiling that were leaking air into the attic. If you have two AC units and only 4 vents total in your unit I think you are correct that you are pushing to much air for the vents you have.

[PMSPKS]

Clif,
Is your 305 ducted for two A/C's? I have a 2010 325CK and just added a second A/C to the bedroom. It was not wired for a second A/C, and could not tie into the existing duct. Yours may or may not be set up to tie into the existing duct. I'm like Keith though, if it is designed to tie into the same duct, I think you will not have enough duct capacity.

[avvidclif]

I currently have the CF285RL and it has 4 ducts. It was wired for a bedroom ac which was added. It also ties into the existing ductwork. The 305 is a trailer I am looking at and is wired for a bedroom ac. As to whether or not it is tied into the existing duct I don't know.

That's interesting Keith and makes me wonder why I'm so short on ducts??? Oversight like in the Rushmore series or what.

[Lloyd]

Cliff, what's possessing you to want a new rig?
You don't have the old one even close to being broke in yet.