matt said:

I have a marine air Vector 12kbtu a/c unit. it is model # VRX12k. it is about 13 years old but appears to have little to no use. it is behaving strangely/not working…here are the symptoms:

when powered on, usually the fan comes on no matter what settings are on the control unit. it could be in 'cool' with a set temp of 75 and an ambient of 65 and the fan will come on. but, then again, sometimes the fan doesn't come on when powered on. just seems strange.…For now I would not be concerned with this…It may be you are seeing it power up doing what it was last doing when power was shut off…It has a perment memory.

when powered on and set to have the a/c come on (e.g. set point of 65 with an ambient of 80), usually what happens is that the fan immediately comes on and you hear 2 'relay' clicks (assuming that's what i'm hearing) and then nothing happens and the fan continues to run. the compressor does not start and the water pump does not come on. after turning it on and off 10 or so times over a 2 day period, the compressor did come on once and the water pump as well but after 10 minutes or so they both turned off (not sure if it was simultanteous or one before the other)….How long are you waiting for it to do something before turning it back off ?

i took voltage readings at the compressor and there didn't appear to be any voltage. i'm not sure what the voltages should be as there is a start and run wire, etc. i convinced myself it is a faulty control board and removed it from the boat. how can i troubleshoot this.

oh, and the display unit does not show any error messages. it seems to think everything is fine.

thanks.

Hi Matt~

You should have the ECU Maxx control on that unit…Does the cool or heat light next to the mode button ever light ?…If it does what happens then ?

Have you tried the cooling only mode ? (by pressing the mode button)

Steve~

Unfortunatley Matt…It sounds like you have control troubles…My thought is the board…Problem is a replacement board for the ECU Maxx is over $1000.00…Yes thats one thousand dollars….For the board only…

Last school I attended they would not even talk about the Maxx…I asked why & they said "We just aren't Going There"

You can have a retrofit kit to the new Passport I/O for $590.00

Thats Keypad & bezel (to fill your hole) Board, 15' cable, manual & quick reference card.

Steve~

It would be hard for me to say if your 13 year old unit is worth $590 + freight…I can't see it…I did recently sell a used unit with control (still shown in my store) for $600 + freight…Used units that are good enough to sell are hard to come by…Usually when we take them out down here in Fl…They are pretty much used up…

A new replacement unit is closer to $3000.00 with control + freight…But it is Lighter, moves more air, smaller, quieter & has a composite drain pan that won't rust or allow standing water.

In your case…If I had to guess what is bad on your board I would say it's a triac or relay, or two…But board parts are not offered by Marine Air. 

Steve~

HEY GUYS I HAVE A 1990 SEARAY EXPRESS 350 AND I'M HAVE A/C TROUBLES I CAN'T TURN IT ALL THE WAY UP AND AFTER RUNNING FOR A WHILE IT ICES UP AND BLOWS WARM ALSO THE HEAT DOES'NT WORK I'M ON SURE WHAT KIND OF UNIT IT IS. DOES ANYONE HAVE ANY IDEAS [BY THE WAY I'M NEW SO I HOPE I'M DOING THIS RIGHT]

Post edited 4:55 pm – July 29, 2010 by Captain_Zap

I have 3 Marine Air 12k Vector Compact units on my boat with the Passport digital controls, circa 1998. I have had three units fail as you describe over a period of 5 years (fan only, no compressor or pump activation) and I figured out the cause and repaired it. It takes excellent electronic technician skills so is not for the amateur, but here goes:

These units have a design problem on the circuit board (the one inside the main unit) which causes a circuit board connecting via (plated hole connecting the top and bottom layers of copper) to blow after a few thousand relay cycles of the main compressor/pump relay. The via is not sized properly and it overheats and eventually goes open circuit. You will have to remove the circuit board from the A/C unit, unsolder the large relay K1, and inspect the two holes near the terminal block. The one near the transformer is usually the one that goes. The via can be repaired with a hollow copper rivet. This will improve the current handling capability and fix the problem. Next, since the relay usually gets wounded by the heat of the failure, replace the relay with Tyco T90S1D12-5, available from http://www.digikey.com as part number PB109-ND for $2.88. Solder in the new relay and chances are the circuit board will be as good as new.