Water pump acting weird

[John Young]

Just installed a larger pressure tank on our water system..

The water pump does a great job, but as it nears the cut off pressure, it starts to flicker on and off until it reaches the final shut off pressure.

Any idea of I have a bad switch or if I can fix this without replacing a pump?

Thanks!

[rvfirefighter]

Make sure the by-pass valve for using the pump to winterize a unit is shut-off completely. I had a problem similar to this when I got this unit, they replaced the pump, but it turned out this was the problem. Hope this cures your problem.

[H. John Kohl]

I am thinking back about 50 years when we had to purge our water pump. I have a 1 gallon accumulator to install, so my comment is assumption at this time with no proof, but it may be some air in the accumulator or close to the pump causing the pump to (surge) towards the end until it has reached max pressure. Air is more elastic when compressed than water so it may be bouncing when close to the max pressure. If it is air then you need to bleed it off.
Do you have a picture of your installation. Can you see your water lines to see if there is any air there? How long did you let the water run through the lines? Was there an indication of some air in them?

Please let us know what you find out.

[grampachet]

I believe H may be incorrect. I recall as an old well driller/pump installer the lack of air could cause the pump to cycle. Since air compresses and water does not (very little) the surging happens when the tank is 'water logged'. The new type of tanks with a bladder (basically an inner tube) prevents the water/air contact which allows the water to absorb the air. With these tanks if the bladder is ruptured or leaks the air out of the snifter valve you would begin to get pump surging on and off. Home style tanks have a snifter valve (same air valve on your tires) and you can recharge your bladder (oops that is tank bladder) with air. We would turn off pump, drain off water so there was no pressure on the water system, check the air pressure on the tank at the snifter valve. If there is none or less than the water pressure when used normallym we would add pressure to equal the normal water pressure. Then turn water pump back on and presto all worked again.
Hope that helps.

[H. John Kohl]

Grampachet,
Yea what you say. Thanks for correcting me. As I said it was 50 years ago. Reading your post I guess the thing to check is the new accumulator to make sure it holds air. John Y. good luck and let us know what you find.
Cheers,

[grampachet]

I sure don't know a whole lot but some things I try and remember, at least in part.
Just hope the problem is resolved.

[John Young]

no luck figuring it out so far... gonna talk to the dealer about it..

[John Young]

pressure switch in the pump is supposed to be the problem.. looks like they want to replace the pump

[kmh3212]

The pressure switch is located on the end of the pump. Very, very easy to replace and cheap. One or two small screws and two plug in wires.