jbomba
25-11-2012, 03:59 AM
Hey guys this is my first venture into the world of container refrigeration. Anyway i have been given the task to get this thing going. Got to the container yesterday and found a bunch of loose relays on the board & a faulty CB on the mp3000 box. I replaced a CB and fiddled with the relays and finally got the controller firing up. For some reason the controller had reset itself to factory defaults. Anyway i let the controller do its thing and run its self diagnostics and set the temp to 14 degrees c. The unit fired up and and quickly got to temp. The unit however did not shut off once setpoint had been reached but somehow kept fluctuating between 14 - 17 degrees. I did a bit of reading on the net and came to the conclusion that this thing may be set in continuous mode and not cycle sentry? anyway once it does reach the 14 degrees it seems like unit trys to pump itself down to the point of pulling a vacuum and when it does pull a vacuum the liquid injection solenoid opens and brings the back pressure backup (this all seems very wierd to me) anyway i let the unit run for the night and came back this morning to find ice right back to the liquid line drier. The drier was hot one one side and frozen on the other so i assume this is blocked. I am going to change the drier out today but would still like an explanation on what these systems do when the reach setpoint as i dont see any sory of pressure switch to cut the unit out when it does pump down. If anyone could maybe flick me a service manual for this model container and a manual for the mp3000 controller that would be awesome.