Bouncing pressure switch

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tubig

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Hi , I recently installed a concrete storage tank to supply water to my property , it's fed by a well pump that works well, shuts off when the level in the storage tank is full. the problem here, is between the storage tank and the house. this is the layout: the storage tank is supported by three concrete columns, the tank sits on a reinforced platform approx. height 3.4 meters . water drains from the tank to a Gould's j10s jet pump supported on a platform approx. 1 meter below the storage tank, so there is contious positive head applied to the suction, from the output I installed a check valve ( 1 inch output from pump ). the line then drops to a carbon filter and then to the ground where I've piped it into a 200 liter varem bladder tank ( tank and pump are brand new ) from the bladder tank I installed another check valve and then a ball valve for system shutoff. the settings on the jet pump are 30/60 , I bled off 2psi at the bladder tank , bringing down the bladder tank pressure to 28psi.At first when I initially started the system I did not install a check valve after the booster pump and the pump would run until shutting off at approx. 60 psi ( according to the output pressure guage I installed ) but the guage would promptly bleed down pressure and the pump would start again, until I realized that with the main shut off closed , water was migrating back up the line and into the tank, it's then I installed a second check valve ( backflow preventer ) at the outlet of the booster. Now having done that , when I close the shutoff and attempt to run the booster and pressurize the booster tank , it should shut off at aprox 60psi ( which it did previously ) instead the switch bounces attempting to shut off and on again...currently the only way to run the system is to open at least one faucet in the building, open the main shutoff and throttle the ball valve that supplies water dropped from the storage tank to booster pump , if I attempt to close a faucet or the main shut off downstream from the booster tank the booster pump pressure switch will short cycle , on and off...anyone have any ideas ?? p.s. dimensions on the piping : 1 1/4 inch inlet to booster pump , 1 inch pipe from outlet of pump to main shut off...I'm beginning to think the booster pump is redundant in this setup and the drop from the tank will provide sufficient head , voloume of the storage tank approx. 3 cubic meters
 

Reach4

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4 meters of head will only give you 5.7 PSI. So you probably need the booster pump.

Do not put anything, except for a short length of pipe, between the pressure switch and the pressure tank. What LLigetfa said is true too; if the filter were to clog, the pump would run continually if the filter is between the pump and the pressure switch.
 

DonL

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Why did you put a check valve on the output of the Pump ?

It should only be needed on the Inlet. You are using 2 check valves ? Sounds like Valve #1 is leaking.

Is the switch Mounted on the Pump ?


Good Luck on your project.
 
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LLigetfa

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Where is the pressure switch sense line in relation to the pump, the filter, the second checkvalve, and the bladder tank?

Maybe provide a drawing or pictures that show the layout.
 

tubig

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4 meters of head will only give you 5.7 PSI. So you probably need the booster pump.

Do not put anything, except for a short length of pipe, between the pressure switch and the pressure tank. What LLigetfa said is true too; if the filter were to clog, the pump would run continually if the filter is between the pump and the pressure switch.
Ok , so the pressure switch is located at the pump , and two , removed the filter and left the empty casing , still got the same response from the pressure switch...according to what you're saying I'd have to take down the pump and mount it on the ground ,next to the booster tank, what would be considered a short length of pipe? if I eliminate the filter all together do I still need to move the pump? ( btw I installed the filter between the pump and booster tank to eliminate sediment build up in the bladder )
 

tubig

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Why did you put a check valve on the output of the Pump ?

It should only be needed on the Inlet. You are using 2 check valves ? Sounds like Valve #1 is leaking.

Is the switch Mounted on the Pump ?


Good Luck on your project.
Hi the inlet to the booster pump is a straight vertical drop from the storage tank ( approx. 1 meter ) and I placed a check valve on the outlet of the booster pump because the pump would cycle on , reach the set pressure shut off ( which it's supposed to do ) and then promptly bleed down the pressure , since the system has no leaks the water had to be going somewhere, sure enough it was cycling back thru the pump into the storage tank. I proved this by cycling the pump on and waiting till it attained rated pressure, letting the pump shut off on the pressure switch and then shutting the isolation valve I initially installed at the outlet of the storage tank....and the pressure held , that's why I installed a check valve at the outlet of the booster pump, to prevent back feed to the storage tank, since I've installed the second check valve ( the other is located at the outlet of the booster tank) I got this short cycling pressure switch problem.
 

Reach4

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That desire to keep sediment out of the pressure tank is a common desire. It would make sense for there to be a sediment filter with maybe a 30 PSI bypass to keep the filter from blocking the pump from the pressure switch. I suspect that exists, at least with a separate bypass. I wonder what people would think of that.

I wonder if you could arrange your concrete tank to let the sediment settle there -- although you would need to flush that out periodically.

I don't know what is close enough between the pressure tank and the pressure switch. I am not a pro, but I am thinking 3 ft of 1-1/4 pipe would be OK. The pressure tank should be able to take out the pressure fluctuations that can cause short cycling.
 

tubig

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Where is the pressure switch sense line in relation to the pump, the filter, the second checkvalve, and the bladder tank?

Maybe provide a drawing or pictures that show the layout.
The pressure switch sense line is located in the volute of the pump, the switch itself is an integral part of the pump, it's mounted on the pump. The second check valve is located at the output of the booster pump, to prevent backflow from the booster tank to the storage tank thru the pump, the filter is located between the booster pump and the booster tank, mounted horizontally on one of the pillars that support the storage tank. it's height is between the booster pump and the booster tank , which is mounted on the ground. the bladder tank has a check valve installed at the output to prevent backflow from the building
 

Reach4

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the bladder tank has a check valve installed at the output to prevent backflow from the building

You don't want that check valve. If the hot water expands, you want the pressure tank to be able to absorb that bit of expansion.

I don't know about the other check valve placement.
 

tubig

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That desire to keep sediment out of the pressure tank is a common desire. It would make sense for there to be a sediment filter with maybe a 30 PSI bypass to keep the filter from blocking the pump from the pressure switch. I suspect that exists, at least with a separate bypass. I wonder what people would think of that.

I wonder if you could arrange your concrete tank to let the sediment settle there -- although you would need to flush that out periodically.

I don't know what is close enough between the pressure tank and the pressure switch. I am not a pro, but I am thinking 3 ft of 1-1/4 pipe would be OK. The pressure tank should be able to take out the pressure fluctuations that can cause short cycling.
Ok , as to sediment in the storage tank I've already installed a 5 micron sediment filter between the well pump and the storage tank to alleviate that problem and as I stated before i removed the filter element which is installed between booster pump and booster tank and I still have the same problem of a short cycling pressure switch. So now we're down to the length of pipe between the booster pump and tank, it's currently about 2 meters ( 6 ft )
 

tubig

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You don't want that check valve. If the hot water expands, you want the pressure tank to be able to absorb that bit of expansion.

I don't know about the other check valve placement.
Ok , but this system is only for cold water and I have two faucets that are located about 2 1/2 meters above ground
 

DonL

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You should find out why the First check valve is leaking.

Make Sure it is mounted in the proper position. What kind is it ?

With the switch mounted on the pump, The check Valve on the output of the pump will hose you, Just like what you are seeing.


Good Luck.
 

Reach4

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Ok , but this system is only for cold water and I have two faucets that are located about 2 1/2 meters above ground
What is the purpose of the check valve between your house pipes and the pressure tank?
 

tubig

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What is the purpose of the check valve between your house pipes and the pressure tank?
The purpose of the check valve is to prevent water backflow from the house to the pressure tank....I have two faucets in the building that are mounted about 8 feet above the ground
 

LLigetfa

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You cannot have a checkvalve between the pump and the bladder tank. The checkvalve needs to be on the intake side of the pump so that the pressure from the bladder is seen by the sense line to keep the pump from short cycling.

Reach4, you cannot put any kind of filter between the pump and the bladder tank if the sense line is on the pump.
 

tubig

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You should find out why the First check valve is leaking.

Make Sure it is mounted in the proper position. What kind is it ?

With the switch mounted on the pump, The check Valve on the output of the pump will hose you, Just like what you are seeing.


Good Luck.
Don't think the check valve is leaking because this problem occurs even when the main isolation valve is closed, which is downstream from the check valve. Direction of flow for the check valve is correct...but I think I know now what the problem is ,,,,,the second check valve I installed is located in the wrong place , at the output of the booster pump. Since the sensing line is in the pump volute itself , I need to install check valve at inlet of the pump, that way I'll get the necessary hydraulic lock which the sensing line will detect and shut the pump off
 

DonL

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Don't think the check valve is leaking because this problem occurs even when the main isolation valve is closed, which is downstream from the check valve. Direction of flow for the check valve is correct...but I think I know now what the problem is ,,,,,the second check valve I installed is located in the wrong place , at the output of the booster pump. Since the sensing line is in the pump volute itself , I need to install check valve at inlet of the pump, that way I'll get the necessary hydraulic lock which the sensing line will detect and shut the pump off

I think You are correct.


Good Luck.
 
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