Heatcraft Refrigeration Products 25001501 - Manual (Page 8)

BEACON CONTROLLER
8
OPERATING INSTRUCTIONS
REFRIGERATION MODE
START UP
1. Check all wiring connections to be sure they are correct and tight.
2. Check voltage taps on transformer. The transformer is shipped wired for 240. If your supply voltage is 208
volt systems, charge to 208 voltage tap.
3. Check setting of time delay relay in condensing unit. It should be set at two minutes (the third marker).
4. Check the low pressure switch setting. It must be set to 0 PSIG cut out, 10 PSIG cut in, to allow start and
operation, especially in cold ambients.
5. At initial start-up, the system may cycle off at 4 minutes and display a low superheat error, then restart
itself. This cycle may be repeated a few times. Do not shut the system off. Let the system run, as it may
take a few cycles for the electric expansion valve to attain the correct setting for the desired superheat.
6. Liquid line should always be insulated.
Ambients above 50
°
F
At the initial application of power to the system, the compressor and the evaporator fans will be in a four
minute hold-off cycle and will not start immediately. When there is a call for cooling, the compressor starts
and the electric expansion valve (EEV) stays closed for 12 seconds. After 12 seconds, the EEV goes to
approximately half open and the compressor is put in a four minute “hold-on” cycle. (This means that the
compressor will run for a minimum of four minutes before shutting off.)
When the room thermostat setting becomes satisfied and if the compressor ran for at least four minutes, the
EEV will close and the compressor will pumpdown, then shut off. The evaporator fans will continue to run.
When the room sensor detects a rise in temperature of approximately 2
°
F, and the compressor has been off
for at least four minutes, the EEV opens to its last position 15 seconds before the compressor starts. Super-
heat adjustments at two minute intervals will then follow. During this time, the compressor will be on a
minimum four minute “hold-on” cycle. If the superheat drops to +2
°
F at anytime, the valve will be adjusted at
45 second intervals.
If the compressor discharge line sensor reaches 225
°
F for four minutes, the superheat will be lowered
temporarily, overriding the normal superheat routine to effectively keep the compressor discharge line tem-
perature from going any higher. “Discharge high” fault will be displayed and the system will continue to
operate. A service person should check system to determine cause for high discharge temperature.