Carrier 16JT Series Start Up & Operation Manual

Carrier 16JT Series Start Up & Operation Manual Manual pdf 14 page image

Typical Control Sequence, Normal Start(Fig. 10 and 14)1. When power is supplied to the chiller control panel andthe chiller is not in operation, the Stop light (RL) is on.2. To start up machine, the Cycle-Guard™ switch (43-RV)should be placed in the AUTO. position.When the Start button is depressed, start relay (3X) latchesthe ready state. If the Local/Remote switch is in the localposition, the Run light (GL) also goes on and the run re-lay (2X) energizes to start the chiller. If the switch is inthe remote position, the Run light will go on and 2X willstart the chiller only when the remote control start con-tacts close.The run relay (2X) also starts the chilled water pump ifit is tied into the chiller control circuit for auto. start/stopand its water pump safety contacts are closed.3. If the low load contacts (23C) in the temperature con-troller are closed with a demand for cooling, the start re-lays (1X1 and 1X2) are energized to turn off the Stoplight (RL) and lock out the shutdown dilution function(62T1). Relay 1X2 also starts the cooling water pump andcooling tower fan if they are tied into the chiller controlcircuit for auto. start/stop and their interlocks and safetiesare closed.4. When the chilled water flow switch (69CW) closes, thepump interlock timer (2T1) energizes and closes its con-tacts in about 2 seconds. If, at that time, the chilled waterand cooling water pump contacts (88EP and 88CP), andthe low-chilled water temperature safety (26CW) are allclosed, the system water pump safety interlock relay (CWX)is energized.When the absorber pressure switch relay (ABSX), ma-chine pump safeties (26MX), and 1X1 contacts are alsoclosed, interlock relays (1Y1 and 1Y2) are energized forself-latching and for normal operation of the refrigerantand solution pumps, generator level control, and Cycle-Guard operation.5. If the safeties for the generator conditions (63GX) are alsoclosed, the safety device relay (4X) energizes to latch inthe safety interlock relay (4Y), and to lock out the safetystop relays (30X1 and 30X2), and the alarm buzzer (BZ).The 4X relay also switches the Cycle-Guard valve (20RV)to automatic level switch control, and releases the capac-ity control valve from the closed position. However, theload limiter relay (LIX) is initially deenergized, keepingthe valve at a mid-open position for a soft start. After about15 minutes, time delay relay 62T3 contacts close to en-ergize LIX, releasing the capacity control valve to nor-mal full range control, unless LIX remains deenergizedby the open contacts of the high refrigerant level relay(33RHX).If the solution level in the high-stage generator is not toohigh for normal operation, as determined by the level con-trol electrode and relay (33W), the generator pump(s) (88SP)starts when 1Y2 closes. If it is too high, the pump(s) willstart after the generator solution has fallen to a normallevel.If the evaporator refrigerant level is above the low-levelsafety switch (33RL) when start relay 1X1 is energized,the refrigerant pump start delay timer (62T2) energizes.After approximately 5 minutes, the refrigerant pump (88RP)starts if 1Y2 is also closed. If the evaporator level is toolow, the timer is not energized until the generator can con-centrate the solution enough to raise the refrigerant levelabove the low-level switch.3-1 (ON) — Start Chiller3-1 (OFF) — Stop Chiller3-BZ — Buzzer SilencerBZ — Alarm Buzzer3-VP (ON) — Optional Start Vacuum Pump3-VP (OFF) — Optional Stop Vacuum Pump43-R — Remote Local SwitchGL — Chiller Running LampHM — Running Hour MeterOL1 — Low Flow, Low Chilled Water Temperature LampOL2 — Hermetic Pump Fault LampOL3 — Generator Fault LampOL4 — Optional Vacuum Pump Fault LampRL — Chiller Stopped LampTIC — Temperature Indicating ControllerWL1 — Refrigerant High Level LampWL2 — Dilution Operation LampFig. 12 — Typical Control Panel DoorLEGEND1-23 — Auxiliary Relays2T1 — Time Delay Relay33W — Generator Level Control Relay43-RV — Cycle-Guard Auto. Man.88RP — Refrigerant Pump Starter88SP1 — Solution Pump Starter, No. 188SP2 — Solution Pump Starter, No. 2 (Large Sizes Only)88SSP — Solution Spray Pump Starter (Some Larger Sizes Only)88VP — Optional Vacuum Pump StarterEF1,2 — FusesMCB — Main Circuit BreakerTB — Field Wiring TerminalsTR — TransformerFig. 13 — Typical Control Panel ComponentsArrangement14