AC retrofits and modern controls

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wkearney99

Guru
Joined
Feb 17, 2018
Messages
2,164
Location
USA
Vessel Name
Solstice
Vessel Make
Grand Banks 47 Eastbay FB
The three Marine Air AC units in our boat are original from 2005 and on their way out. My hope is whatever replacement we go with can re-use the existing copper lines, as the labor to re-plumb all of that would get spendy and take quite a while.

If possible I'd like to stick with the locations and wiring the thermostats are using. I think they're Cruisair Q-Logic units. I don't know what controller board is installed.

Anyone have their AC system integrated with NMEA-2000? I'm looking for two things, remote stop/start and monitoring. As in, we're on our way to the boat and want to kick the AC on. Or be able to tell the interior temp of the boat has risen past a certain point and kick on the AC for a while to drop it.

I realize this isn't likely to be a one-vendor solution, and that's fine and perhaps even better than something totally integrated (and likely proprietary). I'm finding that once the data and controls are accessible on a network the options open up considerably. Not without a lot of geek-fiddling, of course, but I'm ok with that.
 

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Some of the Dometic products have N2K capability, but I'm not sure which ones. With Maretron you could monitor temp and control a switch to operate the HVAC.


I'm not sure about the remote on/off part. I've dabbled with a few approaches, non-of which have been a screaming success. I've use a VNC viewer to remotely control a computer on the boat. But the intervening network is usually impenetrable for one reason or another. And I've tried a hacked FTP message passing mechanism. Ironically, that works the best, but everything works in slow motion. I'm sure there are lots of other ways to do it too.
 
Looks like I'm going to have to pop open the existing controller to see what's in there. Like any project I want to avoid replacing more than is necessary, but am willing to do so if a better 'big picture' solution can be achieved.

As in, I don't want to replace the tubing running from the existing compressors and the air handlers. With that I'd prefer to avoid re-running the control wires for the thermostats. The ones for the salon (port and starboard units) wouldn't be terribly difficult. But the one for the staterooms would rack up a fair of a labor, I'm thinking. I mean, anything "can be done" but there's always greater costs when you have to start pulling wires over longer distances.
 
Anyone know if Dometic's 'Smart Touch' thermostats support zones? As in, being able to control different zones from the one connected? It'd be handy to have a way to start/stop all of them without having to touch each one individually.

The Dometic website is disappointly free of any kind of useful in-depth tech info.
 
Call or email this guy. Ask your question to him. He provided me with excellent pre-sale advice in order to try to utilize as much existing as possible. Great on phone as well as email. I’ve posted it before and others had same experience as me.
Mark Bower
Service Technician

Phone (954) 366-2778
mark.bower@dometic.com
 
Awesome, I just sent an e-mail inquiring. Thanks!
 
And the conversation with Mark has been very informative. They're coming out with new thermostats that will have networking features. But that'll be a few months (if not longer, knowing most product intro woes). So the question now is what controller boards am I going to be using and how will they be involved if/when new thermostats come out.

I have to get more detailed info on what's installed now, and what my HVAC subcontractor is considering for replacement. I'd like to avoid buying the wrong things now, only to have to rip-and-replace later. I can't put off the replacement of the split components, but may be able to juggle the thermostats and controller boards.

The new thermostats will require an 8-pin RJ45 connection, as opposed to the 6-pin RJ12 connection used my the QHT thermostats I've got now.

More info to follow as the project progresses...
 
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