Dometic Passport

[kthoennes]

Always something! 1996 Mainship 370, we have two Dometic A/C units, one fore, one aft. The AC units themselves are both Dometic ecd16k's. The thermostats are both Dometic Passports. Not 1's or Passport 2's (as far as I can tell), just plain Passports. Photo below. This weekend the forward thermostat or control panel displayed an "ASF" code which means air sensor fault. The manual says try swapping the data cable to check if it's a cable problem, or swap in another panel to see if it's really the panel, or replace the panel (around $200). I do have the other one in the aft berth but I'm very reluctant to pop it out of its bezel, disconnect it, and then reconnect it to the foward A/C unit as a tester. The aft system is working perfectly well and if I mess it up, then we've got no A/C at all.

Anybody have any real world advice in this scenario? Should I just spring for a new control panel and take my chances? Or is there anything proprietary or special about that data cable? Looks generic to me, maybe I could get a tester/replacement at any computer store. (I did do a search for prior threads and found one guy venting about a failed Passport II, but that's it.) Thanks.

 

[boathealer]

Always something! 1996 Mainship 370, we have two Dometic A/C units, one fore, one aft. The AC units themselves are both Dometic ecd16k's. The thermostats are both Dometic Passports. Not 1's or Passport 2's (as far as I can tell), just plain Passports. Photo below. This weekend the forward thermostat or control panel displayed an "ASF" code which means air sensor fault. The manual says try swapping the data cable to check if it's a cable problem, or swap in another panel to see if it's really the panel, or replace the panel (around $200). I do have the other one in the aft berth but I'm very reluctant to pop it out of its bezel, disconnect it, and then reconnect it to the foward A/C unit as a tester. The aft system is working perfectly well and if I mess it up, then we've got no A/C at all.

Anybody have any real world advice in this scenario? Should I just spring for a new control panel and take my chances? Or is there anything proprietary or special about that data cable? Looks generic to me, maybe I could get a tester/replacement at any computer store. (I did do a search for prior threads and found one guy venting about a failed Passport II, but that's it.) Thanks.View attachment 92198

I think it's just a standard RJ-45 cable. You should be able to just buy a female-to-female connector and connect the two cables together as a test -- joining your good control panel (still in place) to the other system.

 

[Recb]

Over a 17 year period I have had two panels go bad and need replacing. The cabling has never been a problem.

 

[Maerin]

Try some electronic spray cleaner in the socket and the plug for the control panel.


I'm not sure if MicroAir makes the passport panels, but it might be worth giving them a call or an email. I recently had an email exchange with their tech support, very helpful, promptly followed up.

https://www.microair.net/


They do list a display unit replacement for certain Passport displays.

I have an older white Passport display in my parts inventory, since I no longer have the Passport controls on any of my equipment, I could be talked into parting with it. So talk to me.

 

[foggysail]

Interesting! That controller looks almost identical to my Marine Air System. I had one controller fail and it was caused be water/moisture intrusion. The cables are ethernet and can be replaced. I makeup my own cables using two tools. The first is the connector crimping tool and the second is the cable tester to be sure the wires I crimp are going to the right pins on the connectors.

 

[Choices]

I had one acting up, and found the wiring diagram.

You could use a plan household thermostat.

I considered a digital Honeywell.

Mine started working when I cleaned the contacts.

 

[ranger58sb]

Looks like our Marine Airrrr Passport II sensors, but snapped into a larger bezel.

FWIW, ours was (very securely!!) mounted with double-sided sticky tape... so taking it off the wall wasn't a bit issue once we knew how. And the cable is a phone- or ethernet-type, either RJ-11 or RJ-45...

You might mess with U8 and U5 settings, see if changing those and changing back might do something.

Or try cleaning the air sensor -- at the bottom of the inside plate -- with some compressed air, as for dusting computer motherboards.

I've got a spare Passport II control panel, probably make that available if those ideas don't help.

-Chris

 

[Maerin]

Clean the plugs & sockets with contact cleaner as the 1st step. If you have a remote air sensor located on or near the evap coil, you should be able to disconnect the cable on the main board and operate the unit on the sensor built into the display. If the remote sensor is open or otherwise failed, it could cause the fault. Simply unplugging it should take it out of the equation. The replacement sensor isn't a big deal, about $20 or so.

 

[kthoennes]

Thanks so much everybody for all your time and help and advice. Off to the boat tomorrow and I'll see what happens and follow up. Thanks again.

 

[kthoennes]

Well, cleaned the contacts (which looked bright and clean anyway), nope. Tried swapping the data cable with an off-the-shelf cable, dead. Wonder if the Dometic cable is "special" or proprietary in some way after all, or at least in my unit. No remote sensor installed, so that's not a troubleshooting option. Took the control panel housing apart and gave it a blast of computer air, nope. So I pried the aft control unit out of the wall bezel with a thin knife blade, swapped it, and the forward a/c unit came to life and fired right up. (And then I replaced the aft control panel and to my relief the aft a/c unit came back to life.) So I'm off to order a new control panel. About $180, could be worse. Thanks again everyone.