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zliminator
01-17-2007, 07:12 PM
I have a customer with a 1 1/2 HP pump that keeps loosing its prime. He said he tried priming it to no avail. I'm assuming the thing to do is cut the pipe, pull it out of the lake and check the check valve, then replace it.

Dan

Dirty Water
01-17-2007, 07:31 PM
It could be a bad foot valve, or it could be a leak in the suction line.

Does it have a union so you can just disconnect it and pull it out of the lake to check?

laylow1994
01-17-2007, 08:04 PM
yea eithier check valve or a bad suction line i usually come across a bad check valve..... but usually replace the whole thing....

WaterGuru
01-17-2007, 08:18 PM
This could be from a number of things. Fist thing I would do is try to put some back pressure on it at the pump head. This will show if you have a bad seal (I'm sure you do if the pump has run without prime) If the seal is good, or after you replace the seal, do the same thing to check the foot valve/check valve for leaks, proceed from there.

speedbump
01-18-2007, 09:30 AM
I don't know if you have a check valve at the pump or a foot valve in the water. The best and in my opinion only way to install any shallow well pump, jet or centrifugal is with a foot valve. If you have a check valve in front of the pump, you are asking for a bunch of nuclear meltdowns and losses of prime. With the foot valve you pressurize the suction line with the water in it. With a check valve in front of the pump you put the entire line under vacuum a soon as the pump shuts off which can make it very easy to lost prime. Even though the pump casting is full to the check valve, the first thing the pump sees when it starts is that big shot of air that is on the other side of the check valve.

bob...

Wet_Boots
01-18-2007, 11:10 AM
I've replaced the foot valve with a suction-side check right at the inlet, which allows some flexibility on setting up the suction line and inlet strainer. That also eliminates the need to remove the inlet line come wintertime.