Pressure Switch and the Jet Pump-They hate each other

[ActionDave]

I have a pressure switch that won't stay closed long enough to let the jet pump come up to speed. When the pressure drops enough for the switch to close it won't stay closed, bounces back and forth like someone sending Morse code. Jam a screwdriver against the points and the motor runs fine. The set up was inherited by a new owner so nobody knows if it ever worked.

There is a pressure tank, jet pump, cistern in that order from left to right. 1" pipe from the cistern, 3/4 pipe on the discharge. Cuts in at 30 psi, cut out at 50 if I do the screwdriver override. Anything I'm leaving out?

Checked the pressure tank, its good. Put a new pressure switch on and it does the same thing. Regular old SQ D without a low pressure cut off.

 

[Boycedrilling]

Go to your Square D supplier. Ask for a pulsation damper for the pressure switch. If they don't know what you are asking for, get a new supplier. It's a little "sombrero" shaped pice of flexible plastic with a small hole in the tip. It costs maybe a dollar.

 

[Sponsor]

 

[Valveman]

Either your pressure tank is not good as you think it is or there is too much air charge in the tank.

 

[LLigetfa]

All of the above or they located the switch too far from the tank.

 

[ActionDave]

Thanks all.

I know it is hard to rule out the pressure tank or other components unless you are there and do the test hands on.

I got involved because the HO brought his pump into our shop and wanted to know what was wrong with it. I tested it and all was good with the motor and switch. I told him thus and wanted to send him away with my blessing.

"No all is not good," he said.

"You have a plumbing problem," I said.

"My plumber says I have an electrical problem."

"Well, here is your pump, here is some electricity, when I put the two together the pump starts and runs fine."

"Will you come out to my house and check my pump with my electricity and see if it still works."

I'm a sucker when it comes to solving problems so I said yes.

I did not find a stand alone pulsation damper but I did find a pressure switch with that accessory as an option. I will install it and see what happens next.

 

[Texas Wellman]

Run the tubing from the pressure switch to the tank or increase the size of the pipe between the pump and tank.

 

[Valveman]

If you have to use a pulsation dampener something is wrong with the tank. The tank IS the pulsation dampener. Either the tank is bad or is too far from the pressure switch.

Basically same thing TW said. I was typing and didn't mean to step on TW.

 

[ActionDave]

Run the tubing from the pressure switch to the tank or increase the size of the pipe between the pump and tank.

Here's the update. Went out today and moved the tube over to the tank tee. Bingo! Worked great!
Thank you everybody.