Updating AC in 2007 40DA?

[Redhook98]

My AC in my 2007 40DA is getting loud, inefficient and rusted out. It is a 12k Dometic SXF12/2. What is a good upgrade or replacement? I was going to go with a Marinaire 16000, but fear the breaker/wiring, ventilation and water supply may not be up for the challenge of the extra 4k btus.

What have you guys done? Upsized, or stayed the same. I realize we are also talking two different technologies now (2007 vs 2022).

 

[KevinC]

My AC in my 2007 40DA is getting loud, inefficient and rusted out. It is a 12k Dometic SXF12/2. What is a good upgrade or replacement? I was going to go with a Marinaire 16000, but fear the breaker/wiring, ventilation and water supply may not be up for the challenge of the extra 4k btus.

What have you guys done? Upsized, or stayed the same. I realize we are also talking two different technologies now (2007 vs 2022).

Up sizing may cause problems. If the AC cools to fast it doesn't properly remove all the humidity. Then you have a cold damp cabin. This is short cycling. Its all proper sizing.

I would stay close to what was sized originally.

-Kevin

 

[dtfeld]

I replaced my main cabin with a Citi marine and a new touchcreen thermostat this summer. Pretty happy with it. The nice touch is the removable sceen to keep the coils clean. Blow a lot of very cold air. The have a 12k unit, that "should be a drop in replacement, but as always, they are all just enough different you'll need to adjust somewhere. 2 year warranty.

 

[Redhook98]

I replaced my main cabin with a Citi marine and a new touchcreen thermostat this summer. Pretty happy with it. The nice touch is the removable sceen to keep the coils clean. Blow a lot of very cold air. The have a 12k unit, that "should be a drop in replacement, but as always, they are all just enough different you'll need to adjust somewhere. 2 year warranty.

Is that the CTM unit? Did you have to change the cable to the remote, or was it the same cable? What did you have to tweak and what model number was it? Looking to just drop one in. Thanks!

 

[bahamabreisus]

Look into Webasto units, very quiet and very efficient. We have had 3, and totally satisfied.

 

[dtfeld]

Is that the CTM unit? Did you have to change the cable to the remote, or was it the same cable? What did you have to tweak and what model number was it? Looking to just drop one in. Thanks!

Yes, CTM. The new touch screen did require a new remote cable but one of the nice features is the temp probe is inside the remote and I get much better temp control. Also able to enter a schedule just like at the house.

The big difference was the location of the drains, they were a little different, and worked better if I spun the unit 180*. That required a slight modification to the 6” flex duct (that needed replacement any way). This new position also allowed better access to the filter (which was impossible on the old unit). Electrically it was plug and play.

Overall, pretty happy with the results.

 

[ttmott]

The newer HVAC systems are more electrically efficient; however, always check the unit of interest's data sheet for it's electrical requirements and compare for compatibility to your boat's circuit rating.
With the larger system comes a larger fan and the need to deliver more air. So, it's important to ensure the ductwork is up to the task. The question to ask also is - was my system continuously running in the summer months? Or, was it continuously cycling on and off but still maintaining the temperature in the cabin? In Florida, for example, my systems pretty much continuously run so I could naturally step up to larger systems to help better maintain cabin temperatures and not kill the power plant.

 

[dtfeld]

Also, the Webasto units have slightly different duct sizes, and water line sizes if your coming from Dometic…that are pretty up front about it, but may require pre planning the duct and water connections. But they look like pretty nice units, and pricing is pretty good.

It’s not a bad DIY job, but I would expect some small game time adjustments! It is a boat after all!