Condenser Freeze Prevention
This control a lgorithm helps p revent condens er tube freeze -up by energiz ing the condens er
pump relay. If the p ump is controlled by the PIC, starting the pump will hel p prevent the water in
the condenser f rom freezing. Co ndenser freeze prevention can o ccur whenever t he machine is
not running except whe n it is either actively in pu m pdo wn or in Pumpdown Lock out with the
freeze preventio n disabled (r efer to Control Test table, Pumpdown/Termina te Lockout tabl es).
When the CONDENSER REFRIG TEMP is less than or equal to the CONDENSER FREEZE
POINT, or the ENTERING CO ND ENSER WATER temper at ure is less than or equal to t he
CONDENSER FREEZE POINT, then the CONDENSER WATER PUMP shall be energized
until the CONDENSER REFRIG TEMP is greater than the CONDENSER FREEZE POINT plus
5° F (2.7° C). An alarm will be ge nerated if the m achine is in PUM PDOWN mode and th e pump
is energized. An alert wil l be generated if the ma c hin e is not in PUMPDOWN mod e and the
pump is energized. If in re c y c le s hu tdown, the mode shal l tra nsition to a non-rec y c le s hu tdown.
Tower-Fan Re lay
Low condenser wa ter temperature can cause t he chiller to shut down on l ow refrigeran t
temperature. The t ower fan relay, l ocated in the start er, is controll ed by the PIC to ene rgize and
deenergize as the pres sure differential bet ween cooler and conde nser vessels changes in ord er
to prevent low condenser wa ter temperature and to maximize machine efficie ncy. The tower-fan