Well Pump Prime Loss due to Pressure Tank Failure?

Pump prime loss blamed on water pressure tank?

Diagnostic FAQs on how to prime a water well pump:

Questions & answers on how to prime a water pump using a garden hose and a remote water source (from a neighbor).

A "dry" above-ground water pump such as a 1-line jet pump or a 2-line jet pump won't work - the pump has lost its prime. This article provides diagnostic questions & answers that can help you if you're having trouble priming the pump.

This article series describes how to prime a water pump to restore water pressure to a building by priming the well pump to restore the pump to operation after it has lost prime.

Well Pump Priming vs Pressure Tank Failure Q&A

These questions and answers were posted at HOW TO PRIME a WELL or WATER PUMP - be sure to see the detailed procedures we offer there.

Also see our index to all Q&A about priming a pump at WATER PUMP PRIMING DIAGNOSTIC FAQs

Well Pump loses prime: plumber replaced pressure tank, didn't help

First let me say your site is amazing thank you. I have a 2 line jet pump I don't know the well depth. It appears to have been working fine however the shut off valve between the pump and the pressure tank developed a leak so I replaced this along with the T and pressure gauge located at the top of the T.

Got the pump primed and running again and the pressure switch line sprung a leak (pin hole) so I replaced this as well. After these repairs the pump will not shut off it appears to be producing roughly 25-30 psi of pressure so not enough to have is shut off.

I call in a plumber to diagnose the issue they determined that the pressure tank was bad, blatter would not hold pressure and that the pump needed to be replaced because it was running hot.

nes it still will not hit the factory set 50psi switch. I then shut the valve between the pump output and the pressure tank (per your guidance) to see if the lines into the well could have holes, watched the pressure gauge on the pump and it appears to hold pressure at least over the 5-10 minutes that I had to observe. Is this long enough or shall I observe longer?

I ask because I ended up reducing the pressure switch so that the pump would shut down at a lower point and lower the tank pressure to coincide (2#'s lower)

This seemed to work however the pump then lost it's prime and after re-priming it seemed to work again abet it still won't produce more than the 25-30 psi of pressure.

Is this indicating that I have a faulty valve in my well or a leak in one of the lines in the well? 22 July 2015 David

Reply: the water pressure tank would not directly cause loss of pump prime

David, I don't understand the plumber's conclusion.

Even if a pressure tank bladder had failed, the pump would pump the tank up to cut-off pressure and then switch off.

You've done some good diagnostics. I suspect that either the well water level is low or that the pump or impeller is damaged and simply cannot reach cutout pressure. Other problems could cause the same symptom such as a leak in well piping but if that were the case when you shut off the pump you'd see the system pressure drop as water leaked back out through that opening.

Lowering the cutout a bit so that the pump can reach it is an acceptable fix if the lowering is not too much - which you tried.

But the fact that the pump is losing prime suggests an air leak or water leak in the piping or at the pump itself (which, I admit, contradicts the earlier "no pressure drop" that you observed). So we may be looking at a foot valve that fails or fails intermittently.

Over at a companion article WATER PUMP WONT STOP RUNNING at inspectapedia.com/plumbing/Pump_Runs_On.php

we list reasons that a pump may keep on running, that is, not get to the cut-out pressure. Please take a look there and let me know if questions remain.

David said:

Again thank you for your support. I agree I don't understand the plumbers conclusion on the pump the pressure tank I understand it wasn't holding pressure. Pump hot, well the brand new one gets hot to if it runs for a while.

Lesson learned I have a back up pump now it was installed in 1992 so I thought it made sense. So what is baffling me is prior to fixing (replaced) the leaking shut off and the pressure switch line the old pump worked and kept it's prime.

Is it possible the foot valve failed at the same time, this seems odd but possible. I am assuming that my water table is still very high based on the constant rain we've been receiving. My next move is to check again for leak down after I shut the valve and pump and give it a longer time to confirm there's not a leak or faulty foot valve.

My challenge is locating the well as the prior owners didn't have a clue and the bushes have grown extensively to where the logical location would be.

On the bright side I've done everything myself and not paid the $2000 to the plumber to replace a pump that doesn't appear to had a problem. Any additional guidance would be greatly appreciated. David

Reply:

David:

Double-faults can occur but Occam's razor says we should look first for the simplest explanation as it's most likely.

Is it possible that during the repair a pipe connection simply was not perfectly tightened. For example I've found air leaks into piping (and thus potentially loss of prime) when a hose clamp on plastic piping at joints was not quite tight.

A problem is that air leaking in to the lines may not be so easy to detect unless your system has a clear plastic water filter in which you'd see bubbling and frothing. But you might start by tightening or double-hose-clamping every accessible connection.

Can a hole in the water tank bladder causes loss of prime?

If bladder has a hole in it and you trying to prime your pump will that make the pump not want to prime? (Oct 17, 2014) Roy E. Pierce

Reply: three possible answers

Yes, no, yes as follows:

1. Yes but unlikely: in the very short run, water seeping out of the tank and pump into a LARGE pressure tank with a burst bladder might lose pump prime a time or two. But in my opinion that's rather unlikely.
2. No not directly - loss of prime usually means that water has drained backwards out of the pressure tank and pump body and well piping and into the well (or outside somewhere where there's a leak in the well piping
3. And yes indirectly: the short cycling from a waterlogged pressure tank can damage a pump so it will no longer prime. So if the bladder leak caused a waterlogged than that might be the end result.
   

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Continue reading at PRIME the PUMP, HOW TO through the pump priming plug If you do not have such a source available, we provide alternative methods, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• FOOT VALVES
• WATER PUMP PRIMING PROCEDURE
  • PRIME the PUMP using a GARDEN HOSE
  • PRIME THE PUMP BY PRIMING PLUG OPENING
  • PUMP PRIME, REPEATED LOSS
  • WATER VOLUME NEEDED to PRIME THE PUMP
• WATER PRESSURE LOSS DIAGNOSIS & REPAIR if priming the pump is just not working for you
• WELL PIPING CHECK VALVES
• WELL PIPING LEAK DIAGNOSIS

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PUMP PRIME LOSS DUE TO PRESSURE TANK FAILURE FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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