The grate above my sub zero fridge is very hot... The fridge works, but something must not be working above the fridge.

SOURCE: leaking sub zero 650

I fixed my leaking problem by pulling out the vegetable drawer and checking the condensation drain hose. Sure enough, it was clogged and the condensation had nowhere to go but move out toward the front of the fridge, down the left side and onto the floor. Once that drain hose was cleared (with a bendable straw), no more leak!

SOURCE: ICE MAKER SUB ZERO REFIGERATOR

Check water turned on. check ice button switch turned on in fridge. remove juice storage, ice container in freezer, check ice bucket full white plastic flapper to make sure not stuck on a white peg at top. flapper must hang down and be freely movable to signal ice maker to keep busy. If up high will turn off ice maker. Lots of other parts especially heater circuits involved also: fill tube supply heater not working then frozen supply line then no ice. Look for wiring diagram in ziplock behind compressor grille. can order parts at repairclinic.com. logical design, layout, easy to get to sensors, heaters. makes sense if look at it long enough.

SOURCE: sub zero 650 fidge holding at 53 degrees

Most likely you have a leak in the evaporator. Subzero warranties the parts for 12 years. Call them to find out what they will cover. They are agreat company and will be fair with you.

SOURCE: sub zero 632S error code 21

EC 21 has nothing to do with the refigerator. From the 600-2 series service manual page 3-21 EC 21 is Defrost Overheat fault.
The defrost system is only in the freezer and on a completely seperate refrigeration system. Clear the EC by holding the bell key pad down until you here a tone this is going to be a minimum of 15 but can be as long as 30 depending on the generation of your appliance. The part that you will most likely need to replace is the defrost terminator which stops the defrost cycle. You may have also had a problem in the refrigeration section which did fix by yourself, good job.

SOURCE: sub zero 532. freezer works fine --0 degrees.

check the fan that runs between the freezer and the fridge --check fan for ice blockage -debris-or damage / clean or clear blockage --if not running test wiring and connections as well as motor /repair or replace //also check fan damper is not frozen or blocked its flap that opens and closes for air to flow //----ur fridge side is cooled from the the freezer side the cold air is blown in from the freezer if fan or damper is not working correctly than fridge is usually warm and freezer is working properly

Testimonial: "thanks for the help - I will check all your suggestions "