What are pressure at the inlet and outlets of the AHU (water coming from chiller to ahu and ahu to chiller ) there are any standard value?

chilled water pump is calculated based on pressure drop in the last equipment if the last equipment is AHU then u have to calculate pressure loss for 0.25 to 0.35 bar  usually in AHU coil

the maximum pressure rating for the pump is 25 PN that equal to 25 bar head maximum,but the system head is usually less about 20 or so .

in order to maintain the flow rate till the last point the pressure drop is calculate ,

the exact pressure in pressure gauge  depends on  type of system employed.

1) if its district cooling then maximum running pressure is 8 bar in pump room situted al basement level suppose ahu or fahu if on the roof its maximum pressure would be 7 bar .so the pressure gauge should show 7 bar maximum convert it to psi that around 100 psi

2) if there is building with chiller and of height maximum  25 floors then running pressure is 5 bar maximum in pump room situted al basement level suppose and ahu or fahu on the roof its maximum pressure would be 4 bar .so the pressure gauge should show 4 to 4.5 bar maximum convert it to psi that around 60 to 65 psi

That is why we have DPCV (differential pressure control valve) valve situated at the roof level of district cooling type building which maintains the pressure .Its reduces unwanted pressure to built up in the system of chilled water .

excellent answer for engineer chetan sharma , as a real readings it varies from 4.4 bar to 5 bar outlet and inlet respectively the maximum supply pressure for chilled water pump is 8.3 bar the pressure reading is depend on location of AHU I just need to add that 5 bar or 8 bar this is the supply pressure "the maximum needed at the pump outlet", but the operating pressure for any closed loop network is different, we call it nominal operating pressure for the network and it is equal to supply pressure - return pressure, as an example if we have 8 bar supply and 4 bar return so the operating pressure for this network is 4 bars

Inlet pressure (supply pressure) is 8 -8.5 bar and outlet pressure( return pressure) is 4 -5 bar and operating pressure is 4 bar

pressure from the chiller is pumped and circulated in the system of the Chilled Water system by a Primary Pump or chiller pump to a HX Heat Exchanger where this cooled water is absorbed and reciculated to the loads AHU's, FCU's by the secondary pump. This method is employed to minimize pressure drops and ensure sufficient pressure and flow across the chiller first to avoid chiller coil freezing, and to AHU's and loads for cooling the spaces. There is no determined pressure drop or reading as it depends on the TDH of the pump selected. AHU's are typically rated at5 to Kpa minimum.

We can ask OEM for such pressure drops across the Cooling Coils.