Pump & Pressure Tank Issue

[Ghansham]

Hi Guys,
I would really like a little help with my setup.

I have a 0.5 hp pump that is connected to 12L tank with a 30/40 switch (I assume it is 30/40)
The switch and the tank came together, I add a 0.5 HP pump.

The issue I am having, is the pressure builds up to around 30psi and it flickers the pump on and off, when I turn of power, the tank vibrates like a hammering sound.

I have a video but I am not sure If I can upload it.

I would appreciate any help or suggestions from anyone.

 

[Reach4]

a 30/40 switch (I assume it is 30/40)

Usually there would be a 20 psi difference.

The issue I am having, is the pressure builds up to around 30psi and it flickers the pump on and off, when I turn of power, the tank vibrates like a hammering sound.

Measure the precharge air pressure for the pressure tank. It should normally be 2 psi below cut-on pressure with a submersible pump, and 4 or 5 psi below for a jet pump. Air precharge should be measured with the water pressure at zero.

This used to work right, but started acting badly, right?

 

[Sponsor]

 

[LLigetfa]

The issue I am having, is the pressure builds up to around 30psi and it flickers the pump on and off, when I turn of power, the tank vibrates like a hammering sound.

Sounds like the water might be running back to the well. Is the pump a submersible down in the well?

 

[Ghansham]

Usually there would be a 20 psi difference.

Measure the precharge air pressure for the pressure tank. It should normally be 2 psi below cut-on pressure with a submersible pump, and 4 or 5 psi below for a jet pump. Air precharge should be measured with the water pressure at zero.

This used to work right, but started acting badly, right?

Thanks for your response.

Measure the precharge air pressure for the pressure tank.

The pre-charge air pressure that came in the tank is 19 psi. So I guess that is 40/20?

This used to work right, but started acting badly, right?

I never got it to work.

 

[Ghansham]

Sounds like the water might be running back to the well. Is the pump a submersible down in the well?

I am pumping water from 2-450 gal storage tanks. The pump and tank are at the same level.

 

[Ghansham]

This is a image of the switch settings
https://drive.google.com/file/d/1ZUgWB1sp9YbzQ98GfTPaa2ekqVHCYiVj/view

 

[LLigetfa]

I am pumping water from 2-450 gal storage tanks. The pump and tank are at the same level.

Is the pump external to the storage tanks and is there a check valve between the pump and the storage tanks? When you turn off the pump, does the pressure drop without any water use?

 

[Ghansham]

Is the pump external to the storage tanks and is there a check valve between the pump and the storage tanks? When you turn off the pump, does the pressure drop without any water use?

I meant the water source is 2 - 450gal water tanks, YES its external to the pump. There is a check valve at the inlet of the pump and outlet.

 

[LLigetfa]

There is a check valve at the inlet of the pump and outlet.

There should not be a check valve on the outlet of the pump.

 

[Ghansham]

There should not be a check valve on the outlet of the pump.

For clarification, the check valve is on the discharge of the pump. So it will prevent backflow. That's my reason for using it.

 

[LLigetfa]

The purpose of the check valve on the pump inlet is to prevent backflow. The pump should always be seeing the pressure. Where is the sense line for the pressure switch connected? Post a picture of the pump and tank showing the connection in between.

 

[Midriller]

Remove check valve on outlet of pump and what is the pressure switch on the pump or tank? What is the distance and pipe size between the two?

 

[Ghansham]

Here's a video of what happens. After the flickering begins, I turn off power.
https://drive.google.com/file/d/1xTfCEOLT-rStFgzQkke-_0nR_aIdtzz6/view

 

[Ghansham]

Where is the sense line for the pressure switch connected? Post a picture of the pump and tank showing the connection in between.

See the video.

 

[Valveman]

Yeah you need a check valve on the suction side of the pump. The sound and drop in pressure is the water from the tank going backwards through that gear type pump.