Heatcraft Refrigeration Products H-IM-79B - Manual (Page 16)

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STATUS INDICATOR LED
• ERRORS E 1 - Room temperature sensor shorted, open or not installed
E 2 - Defrost temperature sensor shorted, open or not
installed
E 3 - Suction temperature sensor shorted, open or not
installed
E 4 - Suction pressure transducer shorted, open or not
installed
E 5 - Outdoor temperature sensor shorted
E 6 - Low superheat during cooling
E 7 - Compressor shutdown (high or low refrigerant pressure
or low oil pressure)
E 9 - Multi-in/Multi-out wiring error
• OTHERS Coo - Room Temperature sensor open or not connected
(Instead of displaying box temperature)
Loc - Board is locked. Settings cannot be changed
UnL - Unlock the board settings
LOW AMBIENT OPERATION
All units are shipped standard with Head Master valves. (Scroll compressor units have a
100 Psi Head Master valve and all other systems have a 180 Psi head master valve.)
Condensing units with
multiple condenser fans will have one or more fans cycle on
Pressure Fan Cycling switch.
An adjustable Time Delay relay, factory set at 1 minute, is wired across the Low Pressure
switch (LPS). In cold ambient this allows time for the suction pressure to build up and
prevent nuisance tripping of the LPS.
Pumpdown
At the end of each cooling cycle, when the box temperature is met, the Beacon system will
pump down and shut off the compressor.
To pumpdown, the EEV closes and the compressor runs until one of the following occurs:
•
the Low Pressure Switch opens
• the suction pressure at the evaporator is 4 psig
• a total of two minutes has elapsed.
When any of these three conditions occurs the compressor will turn off and not restart until
there is a call for cooling or a periodic pumpdown.
Periodic pumpdown
While in the OFF cycle, if there isn’t a call for cooling (Box setpoint temperature is met) but:
•
the evaporator suction pressure has risen to 10 psig
• the low pressure switch has closed
The system will initiate pumpdown. This periodic pumpdown will occur at 4 minute intervals
when these two conditions are met.
Status Indicator LED