pressure system switch chatter

I have a pressurized lake pump system that I installed and it is kicking my butt! I can't seem to stop the pump chatter. After reading your other post, I might have figured the problem out. But am unsure. I used a PRE-CHARGED bladder tank and the pump makes about 45 pounds. I think the tank is pre-charged to 28 PSI (which would be too high for the cut-in pressure on the switch). Would this be my problem or should the check valve be in a different spot other than out by the filter in the lake (like normal systems) , ORRRRR? This forum is really informative and I would respect any of your answers. One other thing the owner has a PVC lake screen with an internal check valve. It is not like the brass ones we use and it may be slow acting. I have done many pressurized system over the years and this never has happened.

 

Are you sampling the pressure at the pump or at the Tee? If at the pump, try at the Tee. Square D makes a version of switch with a pulsation plug.

 

I had tried both ways. Right now, the tank and p-switch are at the other end of the main line. This is what I usually do with higher pressure pumps to slow down the speed of the pump catching up. I just did another one yesterday with the same pump and sampling at the pump. This was a repair with a different pump than original. It had a smaller (original) tank off the top of the pump and it works fine. This one had a regular brass check out by the lake screen. Most of my stuff has elevation to help me. This one does not.
Could a tank that has too much PSI cause this to happen?

 

On a tank precharged to 28 PSI, the pump should be set to kick in at about 30 PSI. If the pump is set to start at a lower pressure, let some air out of the tank.

 

Welcome to Terry's Forum's rfrrace,


What is the model of your pump ?


DonL

 

This is a real basic "Red Lion" 1.5 HP Centrifigal. It will make at best 45 PSI . 42-43 is usual.

 

I know that and did not check it at the time, one of the biggest electrical storms in a while moved in while we were trying to finish. What I would like to know is, could that cause my problem (process of elimination).

 

If there is too much precharge the tank cannot cushion the pulses from the pump so it's not unreasonable that the switch may bounce.

Given the make and model of pump, I would guess that the pressure switch may be set to turn on at no more than 20 PSI and turn off at no more than 40 PSI.

 

If the pre-charge is set for 28psi as indicated in your original post, then it should never turn off if the cut out is 50psi.

I would try a tank pre-charge of 18 and a cutout of 40.

That is about the best that you can expect if indeed your pump only makes 40 psi reliably. Or use a different pump.


Enjoy your project.


DonL


P.S. It looks like the wrong pump for the job at hand. That pump is not made for use with a pressure tank.
It is made for sprinkler systems and the like. I do believe.
http://www.redlionproducts.com/v4/pdfs/Own_Man/228072_008_01_1813442.pdf

 

The pump is not a high pressure pump, but is a very commonly used sprinkler pump in the area. The reason I use it is because the pumps work harder and cycle less with the hose users. I checked the tank pressure (with no pressure in the system) and not only was it too high, but was almost 10 PSI than factory spec. I dropped it to 17 PSI and the chatter seems to have gone away. Thanks everyone for all your suggestions and will keep this forum in my favorites!

 

Any pump will benefit from having a pressure tank to buffer the supply and limit cycling.

 

I agree, to a degree. I was just going by the manufacture recommendation, for that pump.
It is made to run continuous, and not be cycled on and off.

I am glad it is now working.


Have a great day.


DonL