Home > Parts > Pat's TECH TIPS BLOG > Transfer Hose Size From Your Pump to the Proportioner

I got an email today that was a good one.

We sell our stainless braided, transfer hose that runs from your drum pump to the Proportioner.

Our line is only 3/8" ID and the customer was concerned because his OEM hose is 3/4". He was concerned that the hose would not be able to handle the fluid flowing to the proportioner.The Graco, IPM and Gama pumps all have the same flow rate of 5gpm (50 lpm).

Thats a total flow capacity of 10 GPM (100 LPM) that can go to your propotioner. If you spray a standard 01 (AR42) chamber, your spraying at 1.2 GPM (10.20 LPM) And that flow rate is if you hold the trigger down and never release it.

SO, we have 1.2 GPM (10.20 LPM) total, but split into to fluid lines = .60 GPM (6 LPM)

I think I can Pee that hard after a few beers at the Hofbrauhaus House in Munich. In fact, I feel fairly confident I did.

I also noticed that the pressure rating on the OEM hose I saw was 3000psi. Your 2:1 ratio pump is only 200psi if your air inlet pressure is 100psi. (1:1 ratio and 2:1 ratio means inlet air pressure x1 or x2 is what the pressure is going out of the transfer pump)Bottom line -

Why do you think you need a 3/4", 3000psi hose to flow .6 GPM at 200psi a distance of 6 feet from the drum? I understand that cold weather makes the fluid thick and harder to flow. Very true, but your fluids are supposed to be at 70F minimum prior to hitting the proportioner heaters.The industry standard flow rate for 3/8 Hydraulic line is rated at 7 GPM and for 3/8 pipe is 12 GPM. Don't forget, you're all flowing through 3/8" heated hose and drop to a 1/4" whip at the gun.