Dometic/Cruisair controls

[Hurricane]

Does anyone know of a good supply for Dometic/Cruisair controls.
It seems to me that all this stuff is obsolete.
If I were specifying A/C on a boat, I definitely would NOT specify anything made or distributed by Dometic.
Any after sales is hopeless.

This thread got close
Cruisair (Dometic) Control Board

From the links in that post, I contacted Citymarine Store via their online chat service.
They were very helpful but their advice didn't make sense.
I think they have some obsolete kit and are just trying to sell it off.

I'm specifically looking for the SMXht keypad controller.
One of these



There must be thousands of these controllers out there.
People are going to need spares.
Surely I don't have to replace the whole A/C system when all I need is a new thermostat?

Anyone have any helpful contacts?

 

[Baggywrinkle]

Cruisair-SMX-Qht Control Display -AC Display-Climax marine

SMXQht Display Control - Fits Dometic and Cruisair | 722200201

 

[Hurricane]

Cruisair-SMX-Qht Control Display -AC Display-Climax marine

SMXQht Display Control - Fits Dometic and Cruisair | 722200201

Thanks for posting but I think the SMX-Qht isn't a replacement for the SMXht.
Unless someone knows otherwise.

 

[Baggywrinkle]

Thanks for posting but I think the SMX-Qht isn't a replacement for the SMXht.
Unless someone knows otherwise.

You're right ... Q systems only. This one perhaps?

Cruisair - SMXht Control Display - Climax marine

 

[kashurst]

What's wrong with it? I had a similar module start playing up and it was the thermistor that senses temperature.

 

[Hurricane]

What's wrong with it? I had a similar module start playing up and it was the thermistor that senses temperature.

I swapped it from one system to another and the problem moved to the other system.
I take your point though - there is a return air detector also connected to the system.

I have a trick though when I next go out. There is an option to reset to factory defaults. Not sure if that factory reset is for the keypad or the complete system.

 

[Hurricane]

You're right ... Q systems only. This one perhaps?

Cruisair - SMXht Control Display - Climax marine

Thanks - I wonder how good that supply is and it seems a little expensive - maybe the price includes taxes????
Thanks for posting anyway.

 

[Baggywrinkle]

Thanks - I wonder how good that supply is and it seems a little expensive - maybe the price includes taxes????
Thanks for posting anyway.

I've never used them so I don't know .... proceed with caution?

 

[hinch]

give these guys a try they provided me with some control boards (new versions drop in replacements) for my nackered AC unit, in the end we ended up having to change it anyway as the compressor had seized but anyway these guys helped Advanced Marine Cooling Systems from Nauticool

 

[Simi]

One of my controllers is showing LC when turned on and won’t work anyone know what the problem is and how to cure it

 

[Hurricane]

One of my controllers is showing LC when turned on and won’t work anyone know what the problem is and how to cure it

Are you sure it is showing LC - not LO

Extract from the manual

 

[Simi]

Defiantly LC I have read if you press the 2 right hand buttons at the same time it should clear it but it does not

 

[Hurricane]

Defiantly LC I have read if you press the 2 right hand buttons at the same time it should clear it but it does not

Have you tried a Factory Reset?

 

[Simi]

Thanks I will try that next time I’m there

 

[Hurricane]

Thanks I will try that next time I’m there

Please let me know because I'm hoping that will fix mine.
I won't be on the boat until next month to give it a try.

 

[vas]

out of curiosity, what do these controllers really do?
turn on/off the unit, change fan speed, read/set temp and act upon?
do they have some comms protocol to the main chiller (whatever you have there)
I'm asking as maybe that would be a nice project for a rpi now that all the other projects are done and you know how much anchor you have out
Luckily mine is only on/off, temp, hot/cool and 3speeds via simple close circuit buttons so should be easy to replace if it fails.

 

[Hurricane]

out of curiosity, what do these controllers really do?
turn on/off the unit, change fan speed, read/set temp and act upon?
do they have some comms protocol to the main chiller (whatever you have there)
I'm asking as maybe that would be a nice project for a rpi now that all the other projects are done and you know how much anchor you have out
Luckily mine is only on/off, temp, hot/cool and 3speeds via simple close circuit buttons so should be easy to replace if it fails.

I have thought along those lines.
Probably easier for you than me because you have more experience in serial driven data/control.

These controllers are only half of the electronics.
Inside the A/C condenser unit, there is a complex card that switches the compressor, evaporator fans and reads Hi/Lo pressures etc.
In that box there are all the big capacitors for the high load devices.
There are 2 off RJ14 connectors on the control card - one goes to a return air temperature detector - the other goes to the SMXht control panel.
The SMXht control panel is made to match the Gewiss light fittings so is usually located in the cabin.

There are 6 wires (RJ14 connected) between the control board and the SMXht controller.
Of course, there is absolutely no information anywhere as to what these wires do.
With more information, it might be possible to build an RPi replacement etc.

I hope that helps

 

[vas]

I have thought along those lines.
Probably easier for you than me because you have more experience in serial driven data/control.

These controllers are only half of the electronics.
Inside the A/C condenser unit, there is a complex card that switches the compressor, evaporator fans and reads Hi/Lo pressures etc.
In that box there are all the big capacitors for the high load devices.
There are 2 off RJ14 connectors on the control card - one goes to a return air temperature detector - the other goes to the SMXht control panel.
The SMXht control panel is made to match the Gewiss light fittings so is usually located in the cabin.

There are 6 wires (RJ14 connected) between the control board and the SMXht controller.
Of course, there is absolutely no information anywhere as to what these wires do.
With more information, it might be possible to build an RPi replacement etc.

I hope that helps

yep, doesn't look like a feasible path, unless you get the protocol and values to setup a small system to log and then reverse engineer.
Not worth it, more to damage than play and gain.

Unless of course you can replace both cards, the one inside the unit and a matching cabin control panel. going low level maybe actually easier as the instructions that the hardware gets and the values that reads are minimal. And pretty sure that's going to be no high currents and all is done via relays or transistors.

 

[Hurricane]

yep, doesn't look like a feasible path, unless you get the protocol and values to setup a small system to log and then reverse engineer.
Not worth it, more to damage than play and gain.

Unless of course you can replace both cards, the one inside the unit and a matching cabin control panel. going low level maybe actually easier as the instructions that the hardware gets and the values that reads are minimal. And pretty sure that's going to be no high currents and all is done via relays or transistors.

Yep
I came to the same conclusion.

If these SMXht ("keypads" - lets call them) aren't going to be available, the only solution I can see is to replace both the compressor control card and the SMXht keypad with their modern equivalent.
Costing in the region of £1000
Disgraceful - bearing in mind how many of these units that Dometic have sold in the past.

 

[vas]

1k is a lot per cabin/compressor...
I'd be impressed if no one has started an open source such project for a microcontroller on the compressor mated to a mobile/small epaper touch screen to give instructions and feedback info to the user wirelessly.
worth a go as a package I think and will be fun keeping the braincells active
but if you go ahead, avoid using onewire protocol temp sensors! or carefully read their async mode properties and configure accordingly!