Heatcraft Refrigeration Products H-IM-79E 用户手册

When a defrost is initiated, the EEV closes, the 
compressor is allowed to pumpdown and shut off. The 
evaporator fans are cycled off and the defrost heaters 
are energized. 

On multiple evaporator systems, all controllers must 
terminate their defrost, either on temperature or fail-safe 
time, before the master controller will end the defrost 
cycle.
There is a 2 minute condensate drain-down period after 
which the compressor is started for a refreeze period. 
The evaporator fan stays off (fan delay). The refreeze 
period will last until the evaporator suction temperature 
is at 28°F or 3 minutes has elapsed. After this sequence, 
the system is back in the refrigerating mode and 
evaporators fans are now running.

The sequence is the same as for electric defrost except 
that there are no heaters and the evaporator fans run 
continuously. If the air defrost for motors are wired 
through the fan relay on the board, they will remain 
energized during defrost mode.

Beacon provides a set of dry contacts for use in 
signaling an alarm. These contacts can be connected 
to a light, a buzzer, a bell etc., which will be activated 
when an alarm condition occurs. When the Beacon II is 
energized, the alarm contacts are OPENED. When an 
alarm condition is detected, the contacts are CLOSED.

Conditions under which the alarm contacts will close are: 
 
 

•   High Box Temperature – LED Display: 

 

 

A 1 - Room temperature has exceeded

 

 

the Alarm High 

ALH value for the Alarm

 

 

time 

ALt, programmed.

Alarms A1 – High Box Temp. and A2 – Low Box Temp. 
will clear automatically if the Box Temp. decreases 
or increases to below or above the Alarm setpoint 
temperature. Placing the system in the 

MODE” or turning off power will clear the A3 Alarm. 

Replacing the Room Sensor, Suction Sensor or Pressure 
Transducer will clear the A4 Alarm.

 

•   Low Box Temperature - LED Display: 

 

 

A 2 - Room temperature has dropped 

 

 

below the Alarm Low 

ALL value for the 

 

 

Alarm time 

ALt, programmed

 

•   System Start-up

failure – LED Display: 

 

 

A 3 - Compressor pumps down and tries

 

 

to restart after 4 minutes. After 4  

 

 

unsuccessful attempts to restart, the  

 

 

alarm code 

A 3 is displayed. System 

 

 

continues trying to restart. 

 

•   Input Fault – LED Display: 

A 4 - Box 

 

 

Temp., Suction Temp., Pressure  

 

 

Transducer open or not installed. 

 

•  Power failure – Loss of power to the 

 

 

Evaporator

 A 1  High Box Temp

 A 2  Low Box temp

   

 

Compressor pumps down and tries to  

 

   

 

restart after 4 minutes

 

A 4  Input Fault

   

 

Box Temp., Suction Temp., Pressure

   

 

Transducer open or not installed