Service manual

6
MASTER-BILT ELECTRONIC REFRIGERATION CONTROL
Display Lay-out
Compressor When power is first turned on to the control, the LED indicator for the Thermostat output will go through
the start-up delay. After a one-minute delay the compressor comes on. The LED indicator stays on while compressor
relay is energized. Display will show actual box temperature. Picture above is the display layout. The compressor will be
cycled off when the actual box temperature reaches its set point. The Thermostat output indicator will be off.
Fan The fans will run constantly for BMG cooler application and off during a defrost for the BLG freezer application.
The Evaporator fan will also cut off when the evaporator temp is above the fan stop temperature setting.
When the BLG freezer in defrost mode; the fan is off until the end of the defrost and the 2 minute drip time has passed.
There is 2 minute delay after a defrost before the fan comes on. If the Evaporator temperature is 35
o
F or below the
controller will override the fan delay. FAN LED indicator is on while FAN relay is energized.
Defrost The control uses time defrost with 4 defrosts per day for the BLG freezer and off cycle defrost for the BMG
cooler.
The BLG time defrost scheme can be re-set the for special applications. During defrost the display will show dEF and
the defrost LED indicator on. The control begins timing the defrost when power is turned on. Four defrost per day
means it will occur every 6 hours. To have defrost occur at 8am, 2pm, 8pm, and 2am then power up at one of these
four times.
MANUAL DEFROST
Defrosting my also be induced manually by keeping the defrost button for 5 seconds. Once defrost has started, the
defrost will go through a defrost and drip time pull down cycle.