Cistern w/ float valve and well pump question

[greenmojo]

All;

I have a 5hp variable frequency drive well pump at 320', connected to a 2500 gallon cistern w/ a float valve that closes the 2" line when the cistern is full. The pressure sensor is located in a Tee fitting in the 2" line and the pump controller is configured at about 20psi.

The problem I am experiencing is that the float valve has an 8" ball on an 18" rod, that bounces when the cistern only needs a few dozen gallons or so, and continues to bounce until eventually it is full. The bouncing not only seems bad for my well pump, but because it is bouncing open/close, it prolongs the abuse on my well pump for a long time. It isn't waves of water causing the bouncing, as I've put a snorkel on it to get the inlet below the water line. It is definitely the pressure from the pump on the valve, pushing the float ball down into the water, and then the ball pushes back and closes the valve, and the cycle continues.

I hope that makes sense.

What can I do to alleviate this? Do I need to put a pressure tank inline to even the pressure? Smaller ball that floats deeper in the water?

Any advice would be very helpful.

~Moses

 

[boggen]

adding more weight, and then adding more floatation, to everything else will not fix issue. you might think ya almost there. then 1 hour later nope.... all over again. well tank is what you need/want.

to note it, i do not think a water hammer resister (spring type) would work either. not enough volume to handle pressure differences.

you could build a diy water hammer resister / pressure tank. out of say 4" pipe. though cost of pipe itself and more so fittings. = a pressure well tank shining like a nice little gem.

you will want to place the pressure well tank near the float valve, as far as connections go.

line from well pump """ T """" well tank
come off the 90 / side of T going to float valve.

above should help a little more with dealing with water hammering and float valve bouncing on/off.

 

[SPIKER]

Couple things can be done

Program the VFD so that when it sees a signal to turn on it delays the start and the stop (slow or extended start/stop time for long ramp up/down in speed) so the pump does not cause big splashing waves.

2nd set the float inside a tube so it isolates the float from wave action (bottom open and float inside w small hole in top)

use two floats a start and a stop which can help make a start as the low level and stop at high level,

put a timers in circuit that delays the start of the pump that float has to be ON for several minutes prior to the pump being aloud to turn on.

M

 

[MossRoad]

Why not put an electronic level sensor in the cistern that controls a relay that turns the pump off and on?

You put one sensor at the high level where you want it to stop filling and another sensor at a lower level when you want the tank to start filling. That eliminates the ball, rod and valve completely. It also eliminates pressure on the pump.

If you're drawing from the cistern, why would you ever need pressure on the pump anyway? Just asking.

 

[MossRoad]

Or something like this...
Zoeller float switches for control of sump pumps and sewage pumps.

Item #1017657
230 Volt Mechanical Double Ball Float Switch for pump down. 15' piggy-back plug. 13 amp maximum.
$121.00

Put that in your cistern and plug your pump into it. Done.

 

[greenmojo]

adding more weight, and then adding more floatation, to everything else will not fix issue. you might think ya almost there. then 1 hour later nope.... all over again. well tank is what you need/want.

you will want to place the pressure well tank near the float valve, as far as connections go.

line from well pump """ T """" well tank
come off the 90 / side of T going to float valve.

ROFL! My initial thoughts were just that... add more weight, etc.

I took your advice, ran down and grabbed a new pressure tank, larger than the one on the house side of the system and then spent all evening swapping tanks. I put the new larger one on the house side, and the smaller and less new tank (1 year old) on the well side. I have the well pump set at 20 psi, so I deflated the well tank to 18 psi to help it equalize pressure.

Incredible... it completely removed all bouncing and surging. THANK YOU! Problem solved.

As for where to put the pressure tank, I have an aerospace engineer friend at Boeing and he educated me a bit, water pressure is omnidirectional, that the pressure tank could be located a 100' away, around a dozen bends and it would still be just as effective. Flow is affected by location, pressure is equalized (equal). Interesting, I learned quite a bit this evening.

Why not put an electronic level sensor in the cistern that controls a relay that turns the pump off and on?

You put one sensor at the high level where you want it to stop filling and another sensor at a lower level when you want the tank to start filling. That eliminates the ball, rod and valve completely. It also eliminates pressure on the pump.

If you're drawing from the cistern, why would you ever need pressure on the pump anyway? Just asking.

I did think about going with an electronic one, however because it is a variable frequency drive controller and pump, it is capable of consuming small amounts of power to pump low water amounts as necessary, rather than hitting my systems with the full 13,300 watts of juice to run my pump at 100%. My property is completely off-grid, and although I have a large power system, I am trying to be as smart as I can with bulk power consumption.

Thank you all again, a long day and night, but I am incredibly excited to goto sleep with this problem solved.

~Moses

 

[Raspy]

Why not put an electronic level sensor in the cistern that controls a relay that turns the pump off and on?

You put one sensor at the high level where you want it to stop filling and another sensor at a lower level when you want the tank to start filling. That eliminates the ball, rod and valve completely. It also eliminates pressure on the pump.

If you're drawing from the cistern, why would you ever need pressure on the pump anyway? Just asking.

That would be a better way. But you can make it simpler yet by just having the lower sensor to start the pump, have it pour into the tank with no restriction and have a time delay relay shut it down instead of an upper sensor.