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Faunsdale, AL | First thing is you need a foot valve that works to prime it by pouring water in it. You also need to bleed air out of the TOP of the pump casing. You can pour the water in anywhere, but you have to get ALL of the air out of the pump. Had a couple of those Berkeley 4X3 centrifugals on 10 horse motors here we used to prewash cows before milking. It was hard to keep a 4” foot valve that would not leak at all, and the pumps would always need priming at least at the beginning of each milking, so we had to plumb up a waterline connection through an approved backflow preventer to keep them primed. We ran the water into the top-most vent plug in the pump casing and since it was rushing in, it would get enough of the air out to allow the pump to prime. Pump was pushing against very little static head and only lifting water 3-4’ from a storage tank as well as the fact that water was rushing into the pump at the same time. Normally you need to get ALL the air out.
If you don’t have a foot valve, then you need a self priming pump, which has a suction check built into it usually, or a way to suck the air out of tbe pump and suction line. That requires a discharge valve between pump and system that works. A ball, butterfly or even a gate valve can work though the classic is a check valve. Problem with most check valves in that service is they eventually start leaking. Ball valve seems to be the most durable but usually the most expensive.
I have used an exhaust driven (eductor) primer, an old York AC compressor belt driven off the engine, a hand pump and the pickup vacuum hose method.
Anything that’s quiet is an advantage since you can hear air leaks. With the engine running, you cannot hear an air leak as big as your finger!
I used a 30# Refrigerant drum as a trap between the pump and the vacuum source. Inlet from pump on top pointing down, outlet to vacuum from very top and a drain valve in bottom to empty it. Used milker hose to make the connections. Clear plastic hose doesn’t stay clear long in the sun, but even black rubber hose works fine because you can see it jump when it starts slugging water. I put some oil in the 30# drum every now and then to keep it from rusting out.
One day I was not using the trap for some reason and got distracted and sucked enough water into a 350 Chevrolet to kill it. It had always died when I would shut the valve as the last of the air was pulled out of the pump and that changed the air-fuel ratio too quickly, so I think it died about the time the water hit it. Anyway, I took plugs out and spun it over and it has been fine ever since. Don’t get distracted!
Edited by ccjersey 8/26/2025 15:05
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Irrigation pump priming how to make easier
