cistern pump problem

[MasterPlumbersKeymaster]

I used to have a 1/2 hp shallow well pump with the pressure tank in an unheated garage. Keeping the tank and pump from freezing has always been a problem. I moved the pressure tank into the house basement which is about 120′ away and replaced the pump with a 3/4 hp submersable in the bottom of the cistern. The control switch is still in the garage and heated when the temp goes below 35. My problem is that when I use water in the house and the pump turns on to replace that used from the pressure tank, it turns on/off/on/off/on/off until the tank is fill again. I can’t seem to get the problem resolved. The pump is a 220v one and I know it is using more power the way it is running and is going to make it fail after a while. I have tried minor adjustments to the on/off setting but nothing seems to work. Any suggestions?

Don

JEANNIE The House That Listens

My Voice Controlled Automated Home
Seen on HGTV

[DUNBARParticipant]

I would first see if the tank has any air left in it.

If water comes out of snifter valve….it is bad.

Could need to replace the pressure switch if the contacts are wore out.

Drain system completely. If the pressure is 2 lbs. less than the cut in pressure.in the tank that is…..your fine. If not…..Make adjustments to correct this so it will operate correctly.

Only check pressure in tank ONLY when the water is out of tank.

[Robert Stephen MortonParticipant]

kyham. what size pipe in the 120ft between pump & tank? What is its condition? Can it freeze up?
Sounds to me that the friction in the delivery pipe is causing the cycling.

Bob

[GarySlusserParticipant]

I suggest you check the air pressure in the tank too but IMO the switch needs to be in the house. The reason for that is the length of the run, elevation if any and friction loses while the switch is problably set at a range of 30/50 or 40/60 psi. That means that the pressure built at the swich is met (switch opens) while the pressure at the house is probably very low but always less than cut-out at the switch as long as you are using water in the house. There are one or two band aid type things I might try if it were my system but I don’t want to suggest them here. Another possiblity is that you don’t have the correct ID pipe for the output (gpm) of the pump and/or you have the wrong pump in the cistern. Wrong being it is putting out water faster than your plumbing is capable of dealing with. Or, as an example, it should have been a 1/2 hp 10 gpm rather than a 3/4 hp 5 gpm.

And hopefully you have the correct gauge electrical cable (amp wise) for that length of run and pump.

Gary
Quality Water Associates

[Author]

Posts