CHILLER OPERATING SEQUENCE Manual mode: Pump and/or chiller will run continuously as manually selected by the operator. Auto mode: Chillers 6 – Duty, 1 - standby CHPP 6 – Duty, 1 - standby CHSP 3 – Duty, 1 - standby Se!uen"e o# o$eration #or "hiller %Primar& $um$ In auto mode, the system will start with one primary pump, one secondary pump and one chiller to ensure minimum fow in the system. Se!uen"e o# start u$ is as #ollo's a !"# shall $i%e on command to "otorised butterfy %al%e &tted on the inlet o' chiller b ('ter $ettin$ the )* status o' "!+ primary pump start command shall be acti%ated c !"# shall chec the waterfow o' the primary pump 'rom the DP & ed across the pump d +low to chiller shall be %eri&ed by !"# 'rom fow switch & ed on outlet o' chiller e I' fow identi&ed , !"# shall $i%e start command to chiller ' !"# shall start secondary pump a'ter $ettin$ fow status o' primary pump he !"# 0ontroller will measure the chilled water return header temperature and compare with preset set point. ith increase in coolin$

Chiller Operating Sequence

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operating sequence chillers when multiple chillers are used

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CHILLER OPERATING SEQUENCE

Manual mode: Pump and/or chiller will run continuously as manually selected by the operator.Auto mode:

Chillers

6 Duty, 1 - standby

CHWPP

6 Duty, 1 - standbyCHWSP

3 Duty, 1 - standby

Sequence of operation for chiller &Primary pump

In auto mode, the system will start with one primary pump, one secondary pump and one chiller to ensure minimum flow in the system.Sequence of start up is as followsa) BMS shall give on command to Motorised butterfly valve fitted on the inlet of chiller

b) After getting the ON status of MBFV primary pump start command shall be activated

c) BMS shall check the waterflow of the primary pump from the DPT fixed across the pump

d) Flow to chiller shall be verified by BMS from flow switch fixed on outlet of chiller

e) If flow identified , BMS shall give start command to chillerf) BMS shall start secondary pump after getting flow status of primary pump

The BMS Controller will measure the chilled water return header temperature and compare with preset set point. With increase in cooling demand, the other primary pumps and chillers will start one by one till the cooling demand is met .

While all chillers are in operational due to cooling load requirement, if one of the chiller trips due to fault BMS shall shut off its MBFV to prevent the flow and turns on the standby chiller as per the sequence of operation described above.Duty cycle of chillers & Pumps shall be changed on weekly / monthly basis (can be as per the requirement of end user)

Please note that BMS will give only on/off command to the chiller. Internal part load performance (loading / unloading of compressors)shall be by chiller internal controls.

VFD Control for secondary pump

The BMS controller will sense the differential pressure across the supply header (installed 2/3rd of te index route)and return header, as the differential pressure decreases, corresponding signal will be send to VFD. The increase the speed of the pumps to meet the pressure requirement if the differential pressure is high, reverse process will occur.

To achieve the above sequence of operation BMS will monitor and control the following points.

Monitoring by BMS

Following signals are monitored by the BMS-System:

Chiller ON/OFF status, HOA status

P/CHWP ON/OFF status, HOA status

S/CHWP ON/OFF status, HOA status

Pressurization ON/OFF status, HOA status, pressure

Chilled water load header supply and return temperature and pressure.

Chiller header supply and return temperature and pressure.

Chiller and header flow status chiller supply and return temperature.

Following fault signals are alarmed in BMS:

Chiller trip status