Glycol Power pack sizing

[trappist]

I am installing a new system. I have a 10 product trunk (with two pairs of glycol lines) and a 5 product trunk (with one pair of glycol lines) the distance from cooler to tap is 50'. So how do i determine the size of the power pack? do I multiply the length by the number of pairs of glycol lines? ie. 50' x 3 = 150' total run? so do i need a pump rated for 250' or will the 125' work? also why do some have two pumps? Thanks in advance

[edramshaw]

You want to determine the total run of the gycol, which including returns would be 300'. There are other factors but that should cover you. Some bigger units have two pumps to ease the stress on longer runs I believe.

[wineglow]

Use the 250' rated unit and get it with 2 pumps. Hook the 10 product to one pump and the 5 product to the other pump. Years down the road if a pump fails you still have half the system working and you could even jumper the two together until you get a replacement pump or motor.