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 generated if th e machine is in
PUMPDOWN
mode and the pum p
is energized. An alert wil l be generated if the ma c hin e is not in
PUMPDOWN
mode and the
pump is energized. If in re c y c le s hu tdown, the mode shal l transition to a non-re cycle shutdown.
Tower-Fan Re lay
This control can be used to assist the condenser water temperature control system (field
supplied). Low conden ser water temperat ur e c an cause the chiller to shu t down on low
refrigerant tempera ture. The tower fan rela y, located in the start er , is controlled by the PIC t o
energize and deenergiz e as the pressure diffe r ent ial between cooler an d condenser vessels
changes in order to preve nt low condenser water t emperature and to max im iz e machine
efficiency. The towe r - fa n relay can only accompl ish this if the relay has bee n added to the
cooling tower tempera ture controller. Th e
TOWER FAN RELAY
is turned on whenever the
CONDENSER WATER PUMP
is running, flow is verif ied, and the differe nce between cooler
and condenser pressur e is m or e than 30 psid (207 kPad) or ent ering condenser wat er
temperature is greate r than 85 F (29 C). The
TOWER FAN RELAY
is deenergized when the
condenser pump is off, f low is lost, the evapora to r refrigerant temper at ure is less than the
override temperat ur e, or the differential pre ssure is less than 28 psi d (193 kPad) and enterin g
condensing wate r is less th an 80 F (27 C).