Cistern pump pulsing

[River Steve]

Three months ago we ran our well to the cistern and started using the cistern to supply our house. The cistern was cleaned, the submersible pump was pulled at that time to have it out of the way. It was put back in place with a new inline back flow preventer as the one built into the top of the pump was not holding pressure. It cycles on and off just fine, everything works as it should except in the last week the pump has started to pulse as it fills the pressure tank. Any idea what might be causing this issue?

I have replaced the pressure switch and the pressure tank, I had a spare for both. When I let water run in the tub and go out to the cistern I can feel the pump pulsing the water line.

 

[Reach4]

I have replaced the pressure switch and the pressure tank, I had a spare for both. When I let water run in the tub and go out to the cistern I can feel the pump pulsing the water line.

Is the pressure switch switching during the pulsing, or is the switch sending power to the pump continuously during the symptom?

How fast is the pulsing? If the pressure switch is going on and off in sync with the pulsing, expect the pressure tank is failing.

 

[Sponsor]

 

[River Steve]

It’s pulsing faster when the pump kicks in and it slows as the pressure is almost to the kick off point. I don’t believe it’s the pressure switch, I have used two switches now and it does the same with both switches. I have switched out both the pressure switch and pressure tank, I was lucky enough to have spares of both here. It still does it.

 

[Reach4]

It’s pulsing faster when the pump kicks in and it slows as the pressure is almost to the kick off point. I don’t believe it’s the pressure switch, I have used two switches now and it does the same with both switches. I have switched out both the pressure switch and pressure tank, I was lucky enough to have spares of both here. It still does it.

Pull the cover off of the switch. Are the contacts switching during the pulsing, or not.

I don't suspect the problem is the pressure switch, but it is where you could maybe see the result of the underlying problem.

Faster is 4 times per second, and slower is 2 times per second?

 

[River Steve]

The hammering on the pipe is so hard at times it can cause the contacts to break apart. If I put my hand on the pipe and steady it, the contacts won’t break apart. I checked the pressure in the pressure tank, it’s spot on. The pulse is like once every one or two seconds, it’s very strong.

 

[Reach4]

Are the contacts switching during the pulsing, or not.

The hammering on the pipe is so hard at times it can cause the contacts to break apart.

I think you are saying that the contacts do open and close with a 1 to 2 second period.

Could we have a photo that include the line from the cistern pump, the pressure switch, the pressure gauge, and the input to the pressure tank?

Also, what is the pressure switch setting, and what is the air precharge. Air precharge is always measured with the water pressure near zero.

 

[River Steve]

I have the pump pulled right now and I’m checking that out. There is a possibility that the pump was bumping the bottom of the cistern. I am going to raise it up a few inches.

The pressure switch is set at 50/70. The air charge is exactly 48PSI. The contacts do not open if I keep hand pressure on the pipe. When the hammering happen it can cause the contacts to open if I’m not holding the pipe.

 

[Reach4]

I have the pump pulled right now and I’m checking that out. There is a possibility that the pump was bumping the bottom of the cistern. I am going to raise it up a few inches.

You might consider pitting the pump into a flow induce sleeve, and having the pump horizontal a few inches above the bottom.

 

[River Steve]

Well the pump failed. I had to replace the pump yesterday afternoon. Everything is working fine now.