Cruisair Showing "--" What does it mean

[GinTonic]

My Boat has 2 cruiseair A/C and they were both working fine until one of them is showing this error message:
"--"

Troubleshooting in the manual says:
Q-Logic display connected to SMXII unit. The two components are not compatible.

Any Help would be appreciated !

[transmitterdan]

Either the cable from the display to the compressor unit is faulty or the computer in the compressor unit will not boot. Try reseating the connectors at both ends of the control cable. Otherwise, you need to investigate the computer control module in the compressor unit. It’s the printed circuit board in a white metal box.

[a64pilot]

Before removing and reseating the cable, I’d remove all power from the thing, not just turn it off.
You may get lucky, it may just be a “glitch” some stray electron went where it wasn’t supposed to?
How many computer controlled things have you turned off and on, to have them work?

[LoudMusic]

When mine did that it seemed to be the temp sensor connection. Or it was the 'daughterboard' with the relay to switch the compressor on and off. On mine that had a weak power connection which I resoldered during trouble shooting. I don't get "--" anymore.

[CaptainMarkS]

Originally Posted by GinTonic

My Boat has 2 cruiseair A/C and they were both working fine until one of them is showing this error message:
"--"

Troubleshooting in the manual says:
Q-Logic display connected to SMXII unit. The two components are not compatible.

Any Help would be appreciated !

Hey, GinTonic. Did you ever manage to solve your issue? I've got the same on my Qht Display for the Cruisair 8,000 BTU STQ8-410A unit. I've reseated the connectors between display and power unit. I've swapped displays with another AC (same issue, so it's not the display). No joy!

[GinTonic]

I tried fixing it with our A/Ctechnician , switched them around with the other A/C unit on the sailboat to no avail. The conclusion is that the circuit board is damaged.

I opted to bridge the circuit board and connect it "direct" . no thermostat, and I put a breaker to turn on and off

[CaptainMarkS]

Originally Posted by GinTonic

My Boat has 2 cruiseair A/C and they were both working fine until one of them is showing this error message:
"--"

Troubleshooting in the manual says:
Q-Logic display connected to SMXII unit. The two components are not compatible.

Any Help would be appreciated !

Originally Posted by GinTonic

I tried fixing it with our A/Ctechnician , switched them around with the other A/C unit on the sailboat to no avail. The conclusion is that the circuit board is damaged.

I opted to bridge the circuit board and connect it "direct" . no thermostat, and I put a breaker to turn on and off

I've established the SMXII unit is faulty (probably the circuit board). How does one bridge this to turn on AC only? The entire unit can be switched on at the breaker but it only activates the fan, not AC compressor.

[GinTonic]

Originally Posted by CaptainMarkS

I've established the SMXII unit is faulty (probably the circuit board). How does one bridge this to turn on AC only? The entire unit can be switched on at the breaker but it only activates the fan, not AC compressor.

My technician bridged the circuit board , the entire unit is switched on at the breaker , I will take a picture next time I am on board next month

[CaptainMarkS]

Originally Posted by GinTonic

My technician bridged the circuit board , the entire unit is switched on at the breaker , I will take a picture next time I am on board next month

Thanks! By the way, I spoke with a technician at Cruisair who said, while this will bypass the SMXII power/logic board, it will also bypass the high pressure sensor which shuts off the unit if there is poor water flow (blockage). Without this, the whole system can be damaged. That was his caveat I'm sharing.