Carrier 16LJ-F Series Operation Manual page 12

Detailed procedure
(1) At the start of the chiller "chilled water pump on-off signal" and "hot water pump on-off signal"
become ON.
(2) Chilled water pump starts in conjunction with the above signal.
(3) This makes the answerback signal return to the chiller.
(4) The chiller control system confirms if the chilled water flow rate is enough.
(5) By clearing the step 3 and 4, both the "cooling water pump on-off signal" and "cooling tower on-off
signal" become ON.
(6) Cooling water pump and cooling tower fan operate.
(7) Interlock signal of the cooling water pump returns to the chiller.
(8) The chiller control system confirms if the cooling water flow rate is enough.
(9) By clearing the step 7 and 8, the chiller operates normally.
(10) Operate the air handling units.
(11) If the above process from 1 to 8 takes more than 10 minutes, interlock alarm comes ON and the
chiller stops operation.
(12) When the chiller receives a stop signal during operation, it starts dilution cycle.
(13) In 1 to 5 minutes after starting the dilution cycle, "cooling water pump on-off signal" and "cooling
tower on-off signal" become OFF.
(14) Cooling water pump and cooling tower fan shall stop.
(15) In one minute the signal of "chilled water pump on-off signal" become OFF but it keeps operating
status with the alarm J-29 "cooling water pump operation malfunction" if cooling water pump does
not stop.
(16) Chilled water pump and Hot water pump shall stop.
(17) Stop the air handling units after completing the step 16.
(18) In 4 to 9 minutes after the step 16, the chiller completes the dilution cycle and stops operation
entirely.
(19) Period of the dilution cycle is 6 minutes at shortest and 15 minutes at longest in cooling mode.
(20) If the ON signal of "cooling water pump on-off signal" comes to the chiller during the period
between the stopping of chilled water pump and the entire shutdown of the chiller or within one
hour after the entire shutdown of the chiller, "chilled water pump on-off signal" becomes ON and
chilled water pump is forced to operate to prevent the chilled water freezing. In this case the alarm
J-29 "cooling water pump operation malfunction" occurs simultaneously.
(21) After one hour of the entire shutdown of the chiller, "chilled water pump on-off signal" or alarm
signals shall not be output even if the ON signal of "cooling water pump interlock signal" comes to
the chiller.
Note
(1) Air handling units shall be stopped after confirming stopping of the chilled water circulation.
(2) Cooling water circulation shall be completely stopped whenever the chilled water stops its
circulation.
(3) Confirmation of the cooling water flow rate is possible with an optional specification of a cooling
water flow switch. (step 8)
(4) The "cooling tower fan on-off signal" should be controlled with cooling water temperature therefore
interlock between the fan and the chiller is not necessary.
(5) Never operate the cooling water pump within one hour after the entire shutdown of the chiller.
Otherwise, the chilled water pump is forced to operate to prevent the chilled water freezing.
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