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Having an issue with my chiller not turning off.

Discussion in 'Hydroponics / Aeroponics' started by Airwalker16, Nov 5, 2017.

  1.  
    Airwalker16

    Airwalker16 Well-Known Member

    So any ideas on what to look for next?
     
  2.  
    drgreentm

    drgreentm Well-Known Member

    Pull the relays and test them out of the unit. Test the contacts for continuity, no (normally open) should have no continuity until the coil is powered and switches the contact to the closed position. If you have continuity on the normally open circuit while out of the unit you have a stuck contact which would cause the compressor to run no matter what the unit tells it.
     
  3.  
    Airwalker16

    Airwalker16 Well-Known Member

    To take the relays out I would have to unsolder them from the back and I don't know if I should really be doing that. Plus I was able to determine earlier today that they both are receiving power when they're supposed to. I don't think it's the relay. But what else could it be that would make the compressor continue to run along with the fan to continually blow heat out of the back?
     
  4.  
    Airwalker16

    Airwalker16 Well-Known Member

    I was able to get a better picture of the back of the PCB as well. Here:
    20171108_133113.jpg
     
  5.  
    drgreentm

    drgreentm Well-Known Member

    When you turn the unit on and set it to your temp, you should hear a audible click from the relay when that temp is reached. The noise is the relays coil dropping out disconnecting the contact which should turn the compressor off. I would turn it on test relay coil power when running (compressor running/cooling) then wait for it to reach set temp and listen for the click, if you don't hear it test relay coil power at this point and if it does not have power to the coil well then I would say the relay contact is stuck.
     
  6.  
    HydroRed

    HydroRed Well-Known Member

    Ok, so after keeping up with this thread, and seeing all the great help and advice offered up I gotta say that what Im taking away from this is that your relays are making open/closed contact and recieving the power they should? It seems the problem is that the relay isnt releasing when it should (hence the need for the unit to be unplugged which allows the relay to close). If this is the case then wouldn't it be the sending unit (thermocoupler) that tells the relay when to open/close? I cant help but think its the thermocoupler that is faulty? The relays only do "what they are told" so to speak.
     
  7.  
    Airwalker16

    Airwalker16 Well-Known Member

    Im under that same suspicion. wish @dstroy would put in his two cents!
     
    Last edited: Nov 9, 2017
  8.  
    Airwalker16

    Airwalker16 Well-Known Member

    I tested the relays all day. I'm pretty sure they're working.
     
  9.  
    Airwalker16

    Airwalker16 Well-Known Member

    Last edited: Nov 8, 2017
    HydroRed likes this.
  10.  
    drgreentm

    drgreentm Well-Known Member

    Nice, glad you sorted it hopefully. Post back and let us know.
     
  11.  
    Airwalker16

    Airwalker16 Well-Known Member

    I havent sorted it yet...
     
  12.  
    HydroRed

    HydroRed Well-Known Member

    Is a replacement for the temp sensor available?
     
  13.  
    Airwalker16

    Airwalker16 Well-Known Member

    Not from eco plus but on eBay there's plenty
     
  14.  
    dstroy

    dstroy Well-Known Member

    Did the compressor/fan stay on while power was off to the relay? If the fan is still on but there is no power to the relay then it’s not the thermocouple. Wish I could help more dude, hard to long distance troubleshoot. Glad you tried though.

    What happens is that sometimes, over time, from normal use, every time relays open (switch power off) and every time they close (switch power on) a little spark is generated no matter how good you design your circuit. That little spark is really, really hot and it can weld contacts together which make relays stick closed when power is removed from the coil.

    If the thermocouple WAS bad, the most common failure indication is incorrect temperature readout. Which is not happening here, as I’ve asked a bunch of times a lot of different ways if that was the case. But it could be the sensor, can’t rule it out completely, because I’m not there :P.
     
  15.  
    Airwalker16

    Airwalker16 Well-Known Member

    Well dstroy, if it was going down to 64,* the Compressor had to have been on.
     
  16.  
    dstroy

    dstroy Well-Known Member

    So the relay is stuck closed then, if it didn’t have power to the coil, but the fan and compressor were on. Just need a new relay, they’re cheap. You did the tests, and figured out what was wrong with your equipment.

    You deserve a high five and a :bigjoint:

    It also tells us that the micro controller and associated circuitry are good, because power was removed from the coil when it should have been.

    It’s bad to assume things when troubleshooting equipment, and best practice to test, no matter what. Sometimes it’s something really minor, that looks like it could be something else.


    One more question though. Do the fan and compressor kick on as soon as you plug the unit in? Assuming that it’s switched on of course.
     
  17.  
    Airwalker16

    Airwalker16 Well-Known Member

    no. When I plug it in the chilling light flashes for 2 or 3 minutes and then it turns on. It's called the standby mode.
    BUT when the temperature is below my set temp, yes, the fan turns on as soon as I plug it in. Then after a little while or sometimes immediately the little red heater light will start to flash and then turns solid and at that exact time I hear and feel the relay click,
     
    Last edited: Nov 9, 2017
  18.  
    Airwalker16

    Airwalker16 Well-Known Member

    I thought from what I posted, that that showed the relays were working correctly? no?
     
  19.  
    Airwalker16

    Airwalker16 Well-Known Member

    I just checked it again and when it turned on the temperature was already at 67. So the power light is the only thing that is staying on. But now that I'm checking these relays all four poles are receiving 13.6 volts or so. So I guess that means that the chiller relay is still receiving power. So I need to change it. But as I was looking at relays online, all of the ones that I see have different pinning than the one on my pcb. Would I just cut the bottom left pin off?
    20171109_115407.jpg 20171109_115743.jpg 20171109_120214.jpg


    I use my pointer finger and thumb from both hands to rest on the relays when it clicks and I'm almost positive that it's the left one with the markings. After the click only one pole is receiving 12.54 volts when before the click all of them were receiving 13.6v. 20171109_121333.jpg
     
    Last edited: Nov 9, 2017
  20.  
    Airwalker16

    Airwalker16 Well-Known Member

    PS I absolutely just heard the relay click for the heater. 100% it went down to 66 and the heater light started flashing as soon as it went solid it clicked very loudly.
    Also before any relays are clicked, voltage is 13.6 or so then afterwards it goes down to 12.54.
     
    Last edited: Nov 9, 2017

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