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(2) "G" Control Board: Auxiliary Code U-1 and Later
At startup, a 5-second delay occurs while the control board conducts an internal timer
check. A beep occurs when the control switch is moved to the "ICE" position. The red
LED indicates proper control voltage and remains on unless a control voltage problem
occurs. The green LEDs through 4 energize and sequence from initial startup as
listed in the table below. Note that the order of the LEDs from the outer edge of the
control board is , 4, 3, . For details, see "II.B. Sequence of Operation."
Sequence Step LED
Energized
Components
Time LEDs are On
Min. Max. Avg.
-Minute Fill Cycle
4 WV minute
Harvest Cycle , 4, Comp, FMR, WV, HGV minutes 0 minutes 3 to 5 minutes
Harvest Pump Timer , 3, Comp, FMR, PM, HGV 0 seconds 50 seconds harvest pump timer
setting
Freeze Cycle Comp, FM/FMR, PM,
LLV
5 minutes freeze timer
setting
30 to 35 minutes
Pump-Out Cycle , 4*, 3, Comp, FMR, WV*, PM,
HGV
0 seconds 0 seconds *pump-out timer
setting
The built-in safeties shut down the unit and have alarms as listed below.
No. of Beeps
(every 3 sec.)
Type of Alarm Notes
High Evaporator Temp.
(temperature > 7°F)
(53°C)
Check for harvest problem (stuck HGV or relay), hot
water entering unit, stuck HM, or shorted thermistor.
Harvest Backup Timer
(harvest > 0 min. for two cycles
in a row)
Check for open thermistor, HGV not opening, TXV or
LLV leaking by, low charge, inefcient Comp, or WRV
leaking by.
3 Freeze Timer
(freeze > freeze timer setting for
two cycles in a row)
Check for F/S stuck closed (up), WV leaking by, HGV
leaking by, PM not pumping, TXV not feeding properly,
LLV not opening, low charge, HM not bypassing, or
inefcient Comp.
To reset the above safeties, press the "ALARM RESET" button with the power supply on.
6 Low Voltage
(9Vac±5% or less)
Red LED turns off if voltage protection operates.
The control voltage safeties automatically reset when
voltage is corrected.
7 High Voltage
(47Vac±5% or more)
Legend: Comp–compressor; FM–fan motor; FMR–fan motor-remote; F/S–oat switch;
HGV–hot gas valve; HM–headmaster (C.P.R.); LLV–liquid line valve; PM–pump
motor; TXV–thermostatic expansion valve; WRV–water regulating valve;
WV–inlet water valve