On 10 May 2007 19:44:21 -0700, wrote:

I pull water from a lake and pump it up to my cottage. For some
reason, my pump has started short cycling. I changed the pressure
switch, and the pressure tank is fully charged (about 38 lbs). It is
primed. If I open the prime port and turn the pump in it shoots water
high into the air - getting water is not the problem.

When the pump comes on, it quickly builds pressure to 40 lbs and then
shuts off, pressure immediatley drops to 20, pump comes on, then off
very rapidly. Would a leak in the line between the jet pump and the
house cause this? I am thinking it might have frozen and split....

First, your pressure tank should be charged to 2 lbs less than the cut
*in* pressure. So if your pump comes on at 20, the tank should be
charged to 18 when completely empty of water. If your cut-in pressure
is 40, then you're ok, but you said the pump stops at 40, so that
doesn't sound right.

Try disconnecting the line to the house and blocking the end from the
tank. (You should have a valve here anyway...) If it builds and holds
pressure, you have a leak in the line to the house.

If it still cycles, you have a leak on the source side, or a bad foot
valve or check valve.



HTH,

Paul