JESSEDIVER49
Senior Member
- Joined
- May 2, 2013
- Messages
- 187
- Location
- USA
- Vessel Name
- Good Vibrations
- Vessel Make
- Grand Banks Classic 42
I have an old Grunert Refrigeration system still running on my '84 Grand Banks. Refrigerant was recharged 18 mos ago and it still cools well but the problem is the control system. It runs 24/7 and the temp controllers do not shut off the compressor at temperature set point. I made a temporary fix by putting the power supply on a timer and I planned to buy new Isotherm systems for my Refrig and Freezer boxes but am now thinking I may be able to extend the life of my Grunert by fixing the temperature control system. I have one compressor/condenser system in my engine room that services both the Refrig Box and the Freezer Box. The temp controller on the Freezer is new but the one for the Refrig is an old Ranco temp controller. My first thought is the Ranco controller may be bad and to replace it with a new Johnson Controls SPST temp controller like the one on the freezer. There is no control schematic available from Grunert because they say this one was a custom made unit. So, I traced the tubing and cables and devices and came up with the attached schematic. If anyone on this forum reading this has expertise on controls systems for refrigerators and can look at this schematic and tell me if they think the most likely culprit is the temperature controller, let me know. I realize the controls are way-old technology using relays for turning the compressor on and off, one from freezer control and other from refrig control. Also, I marked as a "solenoid ?" is a bit confusing to me. It has the small refrigerant line from the refrig going thru it has the refrig control cable going thru it. If anyone with refrig controls expertise can tell me what purpose it serves, pls do.