pressure system switch chatter

[rfrrace]

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.

 

[LLigetfa]

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.

 

[Sponsor]

 

[rfrrace]

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?

 

[LLigetfa]

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.

 

[DonL]

Welcome to Terry's Forum's rfrrace,


What is the model of your pump ?


DonL

 

[rfrrace]

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

 

[rfrrace]

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).

 

[LLigetfa]

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.

 

[DonL]

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

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

 

[rfrrace]

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!

 

[LLigetfa]

P.S. It looks like the wrong pump for the job at hand. That pump is not made for use with a pressure tank.

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

 

[DonL]

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