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problem with marine air system...need help!

Discussion in 'Technical Discussion' started by 54' Bertram, Apr 20, 2010.

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  1. 54' Bertram

    54' Bertram Member

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    I'm hoping one of you guys know the answer to my problem. I recently had a new condensing unit as well as 2 evaporators installed on my boat tied into my SMXir control pad. this weekend we stayed on the boat and the unit ran fine. the last day we were there I had turned on the fan only to move some stale air out. later I walked into the salon and the unit was off. when I turned it on cooling, the control showed the blowers at full speed but there was no air blowing. I checked to see if there was water flow and there was, I checked the condensing unit and the pipe was very cold as was the small tank about the size of a redbull can located next to the compressor. I run up to the flybridge and checked to see if there was poer going to the evaporator units and it was live. I tried turning the system off for 4 hours and restarting again but same result. so I know the condensing unit functions, I know the control pad functions, I know the evaporators are brand new. I'm stumped and hoping there is a simple answer to this. My a/c guy is on a rig and I can't get to him for a few weeks.

    anyone have any suggestions? Thanks!
    Tom
  2. corinthian99

    corinthian99 New Member

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    Hi.
    You don't mention if the fans were actually rotating. Were any of them going?
  3. C4ENG

    C4ENG Senior Member

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    The SMX boards can do some funny things some times. In the past I have had similar problems, maybe some stray voltage effected the board, I am not sure, But I found the programing manual and reset the board back to factory settings. Then the SMX board sent power to the fan unit. It was like resetting a computer.
    You can find the manual on line if you do not have one. It is not complicated, just follow the instruction to get to the programing mode. Then you can also learn how to fine tune your unit. You might then appreciate having had this problem to really learn all the programing functions it has.
  4. 54' Bertram

    54' Bertram Member

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    thanks, I'll try that.
    no the fans were not turning
  5. 54' Bertram

    54' Bertram Member

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    C4ENG, I'll try the reset, but I did note that when I checked the power at the evaporator, it was off when I had the control off, when I turned it on for cooling, the power leads to the evaporator were hot so I don't know if the reset will help but then again, seems like while the evaporators have power, they are waiting for a signal from the control unit to run.
  6. C4ENG

    C4ENG Senior Member

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    I am not sure what power leads you check (and I am thinking that you are referring to the fan units as the evaporators). The fan units will have more than one power lead for the water valve, fan and possibly heating elements.
    I will be curious to know how you make out
  7. 54' Bertram

    54' Bertram Member

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    ahhh....... I checked the 3 wire power line at the connecting point where the wire comes up to the flybridge from the condensing unit in the engine room. from that connecting point the factory pigtail goes into the evaporator assembly to I'm sure several points
  8. C4ENG

    C4ENG Senior Member

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    The SMX panel on the wall will be connected to a control module box hidden some where very hard to find near the fan unit. The fan unit will then be wired from the control module. The control module is what sends the power to the fan unit. It is in that box where you can see if the fan is being sent power, although it does not necessarily mean the fan is receiving the power, as a wire could be broke or something un for seen.
  9. 54' Bertram

    54' Bertram Member

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    I know where the box is located and it has 2 phone cords. 1 comes from the control panel and the other goes to the evaporator. stange that it worked fine one minute and nothing an hour later. boat was docked the entire time
  10. C4ENG

    C4ENG Senior Member

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    If you take the cover off the control module box, you will see where the wires attach and they are labeled on the circuit board for what they do. You will see the wires labeled "Fan". Turn on the SMX board, make sure the set point is turned down for it to call for cooling, then you can see if voltage is being delivered to the fan from the box.

    In the programing mode there is a parameter for split phase motor or shaded pole motors. If that parameter was changed some how for the wrong motor, you could have voltage still and the fan not running. I am sure you have a split phase motor. Just be aware of that one.
  11. Chevelle

    Chevelle New Member

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    Howdy,
    Also be aware that the "phone cord" style connector plus are pretty notorious for failing or making a "bad" connection on some of the pins. Check for this by wiggling the connector around, also spray a little electronics cleaner in there. Just a thought. Sometimes it is the very simplest thing that foils you!
  12. Capt J

    Capt J Senior Member

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    What about a bad ground? if the power leads are hot, the ground could be shorted. I would check that. Also, un-hooking the wires/plug going into the SMX for about 30 seconds and plugging it back in usually gets them working sometimes.
  13. 54' Bertram

    54' Bertram Member

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    ok guys, got to the boat today. inside my control box when I touch the black and the orange (the orange clips on to the post labeled "fan", I get 238 volts.

    when I got to my front evaporator/blower touching the green and white or the green and orange both give me a reading of 119 volts.

    the wall mount control shows the fan speed as on, but no fan is running. I tried the reset, no luck.

    I took 4 pictures, 1 of the cover, 1 of the inside, 1 of the wiring at my front blower unit and 1 of the wiring that comes up to my control box in the flybridge. I can only post 2 at a time so I will post another reply shortly. hope someone has an idea. thanks!
    Tom

    Attached Files:

  14. 54' Bertram

    54' Bertram Member

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    here are the other 2 pictures

    Attached Files:

  15. C4ENG

    C4ENG Senior Member

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    Looking at picture #3, The green should be your ground. If you have 110V between the green and both other wires, then chances are good you have 220V being delivered to the fan, but you should still varify by measuring the voltage between the other two wires.
    If the voltage is there then follow the wire right to the fan motor and make sure there is no breaks/damage and while at the motor, make sure it is a 220V motor. If it is a 110V then you know you burned it up by supplying 220V.
    If the wire and voltage is all good, then disconnect the two power lead wires from the terminal block or go directing to the place the wires conects in the motor if possible (some motors you can, they have a small wire connection box on the side). Turn your meter to continuity and make sure you have continuity between the two wires going through the motor. If you do not see any continuity through the wires, more than likely your motor is toast. Yet you can maybe still get lucky and find something inside the motor that has come loose and then possibly repair it.
    I always take apart an electric motor that has no continuity before I will condemn it for the trash can.
    I will be looking fwd to knowing what the problem was.
  16. 54' Bertram

    54' Bertram Member

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    ok, back at the boat again. so I wanted to check if the voltage was 238 in the front flybridge blower. as I said earlier, touch the green ground with either of the other wires gave me 119 volts. I assumed when I touched the 2 hot wires with my meter, it would read 238. it read nothing. what am I doing wrong? shouldn't it test just like a 110 line? pos and neg give you the reading?
  17. C4ENG

    C4ENG Senior Member

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    There are to many possibilities to try and guess why you do not have 220V delivered to your fan motor, but at least you know why your motor is not coming on now.
    You will just have to start at the control board and work your way to the fan motor. Where you see the one wire on the board labeled "fan", that is only half the voltage being sent. Find where the other half is coming from and start there.
  18. wdrzal

    wdrzal Senior Member

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    Post the electrical schematic for the air handler. Plus any other interconnected systems, IE..... condenser & control wiring.

    Also verify fan motor voltage from tag on motor. Your first picture showed a air handler that is duel voltage . Also many air handlers are rectifying the AC line voltage to DC current for variable speed fan motors.