Suction Side Leak

I have a Goulds 1/2hp shallow well pump, 40ft 1&1/2 plastic pipe, footvalve, and total lift of about 8ft. Recently I developed a leak in the elbow at the top of the down-pipe. So, I made up a new down-pipe using black plastic pipe, barbed plastic fittings, and double clamps. I inserted a PVC union near the top of the down-pipe to make foot valve maintenance easier. I also replaced the footvalve. The result: I still had symptoms of an air leak.

So, I disconnected the union in the well, blew the water out of the pipes, reconnected the union, and pressurized the system with air to 80psi. I then snooped all of the connections for leaks and found none. I let the system sit with air pressure for a bit over an hour, resulting in a loss of one psi (I attribute to temperature differential?)

I drained the tank and checked the bladder - all is OK.

I replaced the pump. I still have symptoms of a suction side leak...and I have a spare pump.

Does it ever happen that something leaks under vacuum but not under pressure? Should I take out the union? Do metallic hose barbs seal tighter than plastic?

I'm really not sure where to go from here and would appreciate any advice.

Thank you,
Jeff

Take a look at "booster pump erratic op" I had the same sort of issue, still do actually.

I would try a brass hose barb instead of the plastic. I found that i had a suction leak at the plastic barb that was between the pump and suction line. Tightening the barb had no effect.

The fewer fittings in a suction line the better. Where is your water level in relation to the pump? And what makes you think you have a suction leak?

bob...

Thank you, everyone, for your help. Bob, the symptoms that I observe are: fluttering pressure gauge, air in the lines when I open the faucet, and a very audible surge sound around the pump and tank immediatly after the pump shuts off. The pump is mounted on top of the tank and the water level is less than 8ft below the pump.

Arnie, I suspected that the plastic barbs might be troublesome in the suction line, so taking yours and Bob's advice, I removed the plastic fittings and union, and installed a well clamped brass 90 at the top of the down pipe.

Now, the system seems to pump up better and the surge I was hearing at the end of the pump cycle is gone. The gauge still flutters and I believe that there is some air trapped in the line that is working out.

Thank you very much for your help. I'm so glad that I stumbled onto this forum; the information and experience is invaluable!

Jeff

Does air come out of the taps every time you open the tap?

When i start my system up in the spring, i also have some air in the lines, but after the water starts flowing, i don't have any air on subsequent opening of taps. I do have to wait a while for water to flow out of the hot water taps, as the hot water tank has to fill first and all the air from the tank has to be expelled.

Sounds like you fixed it. The air in the lines once the pump catches it's prime will evacuate very quickly. Air cannot stay trapped in the lines when the water gains velocity.

bob...

Thanks, gentlemen, for your replies. What I've observed in the past is that the flutter of the gauge seems to reduce over a few days after I have drained the suction line and subsequently, reprimed. I'm guessing that the suction line (1&1/2") may have a rise in it causing an air bubble to be trapped. Since it's burried nearly 4ft deep, it's hard to know for sure.

Jeff