Just like some opinions on a project i am working on.

Have got a ice builder fitted with two pumps feeding a plate heat exchanger and a milk cooling tank.
Pipe run to each is about 20 meter total.

The tank is about 21,000 litres and has two cooling plates with 1 1/2" connections and the plate heat ex. is a two stage job with mains water on first stage and iced water on the second stage. Its a big floor standing one with 2" connections.

The water pumps are about 1.2kw and have 1 1/4" outlets, and i think max flow of 550 L/m.

My plan is to feed the plate heat exchanger with 1 1/2" abs pipe. The outlet of this pump would go to a three way valve so that the pump can be switched between heat exchanger and tank so that once milking is finished all the cooling water can be diverted to the tank and the parlour washing water isn't cooled as it passes through milk side of the heat ex.

I plan to feed the tank with 2" abs, from the other pump and the also the heat exchanger one depending on the position of the three way valve, hence bigger pipe. The 2" pipe would be reduced to 1 1/2" as it is tee'd to the two cooling plates in the tank.

In the opinion of the milking parlour fitters these pipe sizes are too big and will slow down the flow/cooling

Seems to me the less pumping losses due to pipework the better Also there is a provision for extending the parlour in the future so possibly a bigger pump could be fitted to feed the plate cooler. The last one of these i did of this sort of size we fed the plate heat exchanger with 2" pipe at the insistance of the Parlour fitter (different company) and on this site the milk would drop into the tank at between 2.5 and 3.5c

Just like some opinions what you think.

Cheers Jon