A centrifugal pump has an NPSH of 4 metres. It is used to transfer hot wort from kettle, open to atm prsssure, to a whirlpool. Calculate the minimum vertical distance the pump must be positioned below the outlet of the kettle to enable effecient pump operation.

Wort flow rate is 200 hl h-1

Vapour pressure of wort at 100 degrees C = 99 kPa

Wort density = 1065 kg m-3

Pipe length from kettle to pump inlet = 8.5 m

Pipe internal diameter = 75 mm

Pipe friction factor = 0.002

Acc due to grav = 9.81 m s-2

Atm pressure = 101.3 kPa

They've given NPSH = (Ps - Pvp)/qg

Where Ps = Suction pressure at pump inlet

Pvp = vapour pressure of liquid at temp of pumping

q = density of liquid

g = acc due to grav

They've also provided Darcys friction Equation

The examiners tip (its a past exam paper) said that people used equations that enable fast solutions, but expected way was Bernouilli Eq.

Bernouilli Eq:

P2/q + (V2^2)/2 + gz2 = P1/q + (V1^2)/2 + gz1

So P2 is 99,000 Pa

q = 1065 kg m-3

V2 is 200 hl h-1

Z2 = 8.5m

P1 = atmospheric pressure?

I dont have V2

Im looking for z1.

Please help me solve this, answer should be 3.94 m