Schreiber Chillers Modular Chillers - Manual (Page 29)

29
If Chiller is not in use:
In the case the chiller is NOT IN-USED for a period of 30 days or more, it is recommended that the power be
turned off. A plastic cover is recommended to place over the chiller to avoid accumulation of dirt to the chiller,
and also clean the condenser. Water is to be drained from the chiller is not operating for more than two months.
When the chiller restarts, make sure the power is ON for at least three hours prior to turning on the compressor.
The pump can be turned on immediately.
WARNING
Overcharging a refrigeration of air conditioning system can be dangerous
****
If a refrigeration system is overcharged and that it is sufficient to immerse the major parts of the motor and
compressor in liquid refrigerant, a situation has been created which, when followed by unusual circumstances
can lead to compressor housing seam separation or rupture.
The sequence of circumstances that can lead to compressor housing seam separation or rupture may occur in
the following manner:
(a) The system overcharge immerses the compressor motor, piston, connecting rods, cylinder, etc, in liquid
refrigerant, thereby effectively forming a hydraulic block preventing the compressor from starting. This
condition is known as locked rotor.
(b) Electric current continues to flow through the compressor motor windings that become, in effect, electric
resistance heaters. The heat produced begins to vaporize the excessive refrigerant liquid overcharge,
causing a rapid increase in system pressure.
(c) If the system compressor protective devices fail for any reason prior to or during this locked rotor
heating cycle, or cycles, liquid refrigerant may be vaporized sufficiently fast enough to raise the pressure
within the system to extremes far in excess of the housing or weld seam design limits.
(d) In some instances where the amount of refrigerant overcharge is critical in proportion to the system
internal volume, the pressure reached can cause a compressor housing seam separation or rupture,
which can be hazardous.
The remedy to eliminate this exceedingly rare but potential hazard is to use correct refrigerant charging amounts
and techniques.
Tecumseh Products Company urges that all individuals responsible for training, teaching, or advising installation
mechanics and service personnel, must emphasize proper charging techniques and strict adherence to limiting
refrigerant charge amounts to those specifically recommend by the manufacturer of the refrigeration, air
conditioning, or heat pump system.
SERVICE BULLETIN
HERMETIC COMPRESSOR ELECTRICAL TERMINAL VENTING CAN BE DANGEROUS
****
When the insulating material, which supports a hermetic compressor electrical terminal, suddenly disintegrates
due to physical abuse or as a result of an electrical short between the terminal and the compressor housing, the
terminal may be expelled, venting the vaporous and liquid contents of the compressor housing and system.
If the hermetic compressor terminal PROTECTIVE COVER is not properly in place with its weatherproofing
gasket (if required) and bale strap fastening device secured, there is a remote possibility if a terminal vents, that
the vaporous and liquid discharge can be ignited, spouting flames several feet, causing potentially severe or
fatal injury to anyone in its path.
The discharge from a venting terminal can be ignited external to the compressor if the terminal PROTECTIVE
COVER is not properly in place and if the discharge impinges on a sufficient heat source such as, but not limited
to, an open flame, electric heater, or an electric spark.