Schreiber Chillers 2500ACsf - Manual (Page 25)

2500AC
The precautions discussed in this bulletin deal only with those dangers associated with
VENTING TERMINALS.
CRANK CASE HEATERS
This unit has a CRANK CASE HEATER on the compressor. It is important to the life of this
compressor that you follow the instructions. This low wattage heater protects the
compressor when it is idle by producing just enough heat to keep the freon from
accumulating in the compressor. Under certain specific conditions this heater will prevent
the compressor from slugging causing damage to its internal parts.
These Heaters are wired at our factory in such a way that allows the heater to be on any
time the disconnect switch on the chiller is on. When you want to turn the water pump or
refrigeration compressor off, you must only use the manual switches on the electrical
enclosure as marked. When you use the disconnect to turn the unit off, you kill the power
to the crank case heaters. ONLY use the disconnect to turn off power if you are going to
work on the electrical system. When you would like to turn the unit off for the night, do so
at the manual on/off switches. This will leave the power to the crank case heaters. For
this reason, so not use power disconnect.
SPECIAL INSTRUCTIONS FOR CRANK CASE HEATER
When the unit is first received, the power to the chiller should be on for 3 hours. That
means you must, at this time, have the unit disconnect on. The manual water pump and
refrigeration switches should be off. This will allow the refrigeration compressor to warm
up, driving out the freon (R-22) that had migrated to the compressor.
This start up time is necessary if you have all the power off for 12 hours or more. Then you
must allow this same warm up time. It is okay to turn the unit off by the manual switch only
and not the main power. Then you do not need to be concerned about a warm up time.
The crank case heater is HIGH VOLTAGE. But it is only very low wattage. Caution should
be taken when working on the crank case heater to make sure the POWER is off.
Any questions call for more details Schreiber Engineering Corporation 562-926-3855.
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