Was not sure if this is the correct forum but here goes. I have a well, approx 45ft deep, at the bottom of which is a submersible pump. Was originally installed to run a sprinkler system for which it was fine. Now my wife wants to use the water for general garden spraying using a hand held spray. The problem is she switches the pump on then walks to the spray before using it. In the meantime whilst she is walking to the spray the pump is banging away against a dead head, as it will every time she releases the trigger on the spray gun. I have fuffed about with a flow switch on the pipe outlet to fire up the pump only when there is a demand but it is a chicken and egg scenario. No flow = no signal from flow switch= pump does not switch on. What I need is a pump like I have on the central heating , Grundfos, where if there is no flow ie trvs shut the pump just runs ever so slowly until a trv opens then it speeds up. Any idea?
Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws
I don't think there'll be a problem. Centrifugal pumps can run against a closed valve for a while. Hydropneumatic booster sets often have a minimum run timer, to limit pump start frequency, rather than using a bigger air vessel. If maximum allowed start frequency is say 10 per hour, the timer is set to 6 minutes. If demand stops in that time it continues to run, and it works OK. Also as the pump is submerged the heat is dissipated well. And at closed valve it probably draws less electrical power than when pumping.
You could always ask the pump supplier what he thinks.
- May 23, 2015
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Don't see why people are making something simple complicated.
Also has anyone read previous thread?
Also has anyone read previous thread?
You guys dont have many submersible pumps over there do you? You just need a well tank and a pressure switch. Maybe a check valve too if the pump doesnt have one built in.
From pump to check valve then tee for tank and a tapping for the pressure switch then off to your hose spigot. The pressure switch will connect when the pressure is low. The pump runs until the pressure gets high enough to trip the switch off. This should last for at least 45 seconds, preferrably a minute. Then as your wife waters the pressure drops as the tank empties and the switch kicks on again.
The tank will probably need to be around 25gallons. Set the air pressure in the tank to just shy of the switch cut in pressure before you start the pump for the first time.
Modern well tanks have a rubber bladder for the water but a simple tank works too, you'll just have to empty some water and add air every once in a while.
From pump to check valve then tee for tank and a tapping for the pressure switch then off to your hose spigot. The pressure switch will connect when the pressure is low. The pump runs until the pressure gets high enough to trip the switch off. This should last for at least 45 seconds, preferrably a minute. Then as your wife waters the pressure drops as the tank empties and the switch kicks on again.
The tank will probably need to be around 25gallons. Set the air pressure in the tank to just shy of the switch cut in pressure before you start the pump for the first time.
Modern well tanks have a rubber bladder for the water but a simple tank works too, you'll just have to empty some water and add air every once in a while.
That is what I did but it cannot switch the pump on till water flows and water will not flow until the pump is on. Am thinking along same lines as yourself and just having a tee off that just goes back into the well.
It sounds like you just need to install a differential pressure switch to control the bore hole pump. They are are less than £50 just need to know what the pump head is.
So get a pressure relief valve and pipe the discharge back into the well. When you use the garden hose the pressure will drop and the relief will close and the only water coming out will be from the hose.
Mind you this is probably going to work the pump really hard.
We do have submersible pumps over here, and we have hydropneumatic sets as well. BTW, hydropneumatic don’t have just submersible pumps.
For a well supplying all a house’s needs, at any time, a vessel and pressure switch would be all but indispensable, but that’s not the situation here. The OP just wants to start the pump manually when required, and he has confirmed in #8, he doesn’t want to go to the trouble and expense of what you describe. And as I said in #3, I don’t think it’s necessary.
I don’t know how you get 25 gals (US assumed), but that seems oversized. Assuming the water in/out between pump start/stop is ½ that (obviously more details about the application needed to work it out accurately) and maximum 20 starts/h, that’s enough for a pump output over 16 USgpm. For a ½” hose he probably only needs ~ 5 USgpm. In any case, it’s normal to use a smaller vessel than calculated from start frequency, and limit starts by a minimum run timer, as I said in #3.
Unlikely to be necessary if the closed-valve pump pressure is below what the kit can take, as it probably will be.
Exactly !!!
So you have a water supply, an electrical supply, a pump, a (hopefully) fixed metal pipe to the surface then a hose with a gun.
Strip out any flow valve and control it with a "X".
X is staring you all in the face.
KISS (Keep it simple stupid!)
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