Schreiber Chillers 1055 New - Manual (Page 25)

Cryo Compressor Pump
The pump cryo compressor pump is a positive displacement pump capable of delivering 4 GPM. This
flow rate is constant under all conditions. The discharge pressure will vary according to the length of
pipe and the number of fittings in the pipe system. A T-handle pressure relief valve allows adjustment
of the discharge pressure. It should be set to no more than 50 psi.
The cryo compressor pump motor is EXTERNALLY overload protected. In the event of overload,
pump will shut down, and a “CIRCUIT #2 FLOW” alarm will be generated. The overload will
automatically reset, however, the controller flow alarm must be reset.
GCHE/GAHE Pump
The GCHE pump is a 1 HP centrifugal pump. There is a ball valve that short circuits the discharge
and return valve to allow for flow adjustment. The ball valve should be opened so that there is no
more than 35 psi difference between the discharge and return pressure readings for the GCHE
pump. If the pressure is to high, the valve must be opened to divert flow. If it is too low and the not
enough water is going to the GCHE, it must be closed. In order to properly set the valve position, the
adjustments should be made when during a scan when the MR equipment is putting the full heat load
into the chilled water system.
All of the bypassed water returns to the reservoir through the evaporators. The return line water is
diverted to both evaporators.
The pump motor is INTERNALLY overload protected. In the case of an overload the pump will shut
off. The controller will show a “CIRCUIT #1 Flow” error. When the alarm is reset, the pump will restart
if the motor has cooled down to the point where the overload is closed. If the overload is still open,
the controller will try to restart the pump, but will generate another flow error after the pump start up
time delay.
Any time the flow error is reset, the compressors will turn on automatically if cooling is required.
A wye strainer is installed in the return line to prevent the evaporators from fouling. If there is a
noticeable drop in flow, the wye strainer may be full. It can be cleaned by opening the cleanout valve
on the front of the chiller. This must be done while the pump is running. A small bucket should be
place under the valve to catch debris and water that will l=come out of the valve. The valve only
needs to be open for a few seconds.
Chilled Water Reservoir
The insulated chilled water reservoir inside the chiller is designed to eliminate wide swings in
temperature during changing loads. It also provides a convenient location from adding water and
glycol to the system.
A float in the reservoir tells the controller that the water level is too low. The low lever alarm still