Intermittent Pump Flow/Pressure Problem

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Asheville_jeff

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Fingers crossed that maybe someone can point me in the right direction or provide some guidance. I believe my well pump has intermittent flow/pressure production problems. Here goes the sad story... we went on vacation and came back to to no water. A power reset got things going again and after some sleuthing - I found that pressure tank want to water logged. Also - there was huge power bill (over double our normal and weren't even there to enjoy it). I've addressed the tank issue, replaced the pressure switch - but the power bill still while better still seems to be high and correlated to water usage.

After addressing the tank/switch issues - here's the test I've run: Turn shut off valve at tank exit to prevent drainage from pipes in the house. From there I drained the water from tank until the pressure tripped switch and started the pump. I then shut off the tank drain and tracked the time to refill and re-pressurize the tank until the pressure switch tripped again (shutting off pump). It's a 40 gallon tank and is set to 50-70 psi (3 story house - so that top floor needs a bit more pressure). The tank was pre-pressurized for 40-60psi (I increased tank pressure to 48 psi). My pressure switch was initially adjusted to 40-60 psi. I adjusted both to increase the pressure to 50-70 psi (though the trip point seems a good bit lower (42 psi) based on the tests below).

I did three tests, back to back... the pump had not cycled excessively prior to my testing.

Test 1
Start Trip: Kicked on around 55 psi (given my other two readings, which I feel more confident in, maybe I missed this - lots of parallel activities - shut off water drain value, start the timer, look at the amperage pull, read pressure switch)
Amps: Pulls 11.4 - 10.9 amps
Duration: 1 min 37 seconds to get back to pressure
Stop Trip: Shut off at 70 psi

Test 2
Start Trip: Clicked on at 42 psi
Amps: Amperage ~10.9
Duration: Ran for 1:50
Stop Trip: Clicked off at 70 psi

Test 3
Start Trip: Clicked on at 42 psi
Amps: Amperage 10.9
Duration: Ran for 1:56
Stop Trip: Clicked off at 70 psi

Are those re-pressurization times reasonable? Is it possible that the pump, after running for some time, starts to lose ability to pressurize (maybe overheats?). I can add that test after some heavy usage. Any other thoughts on how to test or where my problem might be.

Other potential contributing factors:
There is some sediment in the water and I have a whole house filter - which gets changed intermittently. That can impact flow - though it not impact pressurization since that's after the pump to pressure tank section of piping.

I think I have seen the pump re-pressurize very slowly - though that wasn't replicated in the test above.

Thanks for any/all advice/thoughts/recommendations!
 

Valveman

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A 40 gallon tank only holds 10 gallons of water. 11 amps means it is a 1.5HP pump. Almost 2 minutes to fill 10 gallon tank doesn't sound right. Either you have a 5 GPM pump set really deep, the pump is not producing enough water, or there is a hole in the pipe some where. I am guessing a hole in the pipe since the electric bill is high. Does the pump come on when no one is using water, and/or do you see any air coming out the faucets?
 

Reach4

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my well pump
  1. I initially presumed you have a submersible pump (down the hole), but I later wondered if that was a correct assumption. Submersible?
  2. Does your pressure rise at a significantly faster rate during the first half of the run than the last half of the run time?
 

Asheville_jeff

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Thank you - the information on type of pump HP and concern over duration to pump 10 gallons is hugely helpful. It's a submersible pump. The well is 450 ft deep. I'm not sure the elevation of the pump. The hole is an interesting idea - but I have a couple of counter indicators - we had house cleaners come in while on vacation and this was before I replaced the tank - so that could account for part of the spike. Also my power company recently installed a meter that does daily/hourly monitoring and I see days where the water usage is low that have correspondingly low electric costs (and days where we do things like wash the car have higher consumption spikes). Also, no air at the faucets (assuming this would be like when we've drained the house and turn the water back on - with the water initially coming out in fits and starts). Finally, I've no observed the pump running without water being on or the pressure gauge falling without water being on.

  1. Does your pressure rise at a significantly faster rate during the first half of the run than the last half of the run time? - I'll need to double check, but I seem to recall the last 10 psi being slower the first but not hugely - my gut feel is 50 seconds for the first 18 psi and 65 seconds for the next 10 psi.

It sounds like the pump is having difficulties that may get exacerbated the more water that is used. Given it's shut off a few times, maybe it's right on the edge of being able to slowly make pressure.

I'm guessing I need a new pump.
 

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A 1.5HP pump can only use about $150 a month in electricity, even if it was running 24/7. Most electric bills for a pump doing only a house should be 5-7 bucks a month. It would be hard for a cleaning crew to use enough water to make the electric bill high. How high is the electric bill?
 

Asheville_jeff

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Thanks again for the help sleuthing this. Great questions and I really appreciate the analysis.

The electric bill for June was $262.41, with an average usage of ~75kW hours per day. That dropped significantly when I replaced the tank and pressure switch (I fixed the tank about 1/2 way through July). My current bill is $125 (with an average of 33 kWh per day) - but there is no HVAC being used during that period. I am still seeing spikes of 70+ kWh per day which seem to correlate to high water usage (or at least I think they do). Based on the chart below, I'm starting to second guess myself - this either has been a problem for a while or it's not an issue.

upload_2019-9-3_14-27-48.png


I guess I could test flow rate at the well head... shut off the valve to the house at the pressure tank, let the water in the pipe drain out and then see what kind of flow I get from the faucet on the well? I recall doing this earlier and it seemed very low, but I didn't measure it. This would confirm the above post about how slow the was duration to fill up and re-pressurize the tank.
 
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Valveman

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but there is no HVAC being used during that period. I am still seeing spikes of 70+ kWh per day

So, this pump is also feeding a pump and dump geo system? What is the flow rate required by the heat pump and what flow rate are you actually using? Sometimes the flow restrictor stops working and the heat pump is using too much flow.
 

Asheville_jeff

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Hahahah! Apologies... man did I mess that up. I meant we aren't using the HVAC, not that we had an alternate system. It's cool enough (or at least cools off enough at night) that we don't need to run the air. My point was that bill was as high as it was without any air conditioning or heating, but to really make that relevant, I'd probably need to walk through everything using electricity and confirm that there was no massive ongoing vampire draw. That said - I have seen days with 20kWhr usage - so there is something spiking the meter and it seems to be related to water usage.
 

Valveman

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With no heat pump and just using 300 gallons per day for the house, that pump should only run 30 minutes a day and shouldn't use 10 bucks a month worth of electricity.
 

Asheville_jeff

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With no heat pump and just using 300 gallons per day for the house, that pump should only run 30 minutes a day and shouldn't use 10 bucks a month worth of electricity.

Maybe I just shut the breaker to the pump off for a day and see what kind of load I get, or better yet for a night. I think the new meter monitors down to an hourly level... I can compare a night without the pump to a night with and that should give a good baseline of vampire load and help understand if the pump is pulling power due to a leak.
 

Asheville_jeff

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OK - some additional data... yay!

Flow rate seems to be about 10 gals/min (1 gal every 5-7 seconds). I noticed that after running the pump for maybe 10 minutes, that the maximum achievable pressure was reduced (or at least was reduced from previous testing). The pump just stalled at 65 psi while pulling 10 amps. I had the water to the rest of the house shut-off - so there was nothing pulling water out of the system (other than the potential leak referenced above - though the system does seem to hold pressure - so if there is a leak, it is likely very small).

I then adjusted the pressure switch to reduce the shut off pressure (hi-end pressure using the small nut) from 70 psi to 65 psi. It took 4 full turns to get the switch to click. (4 turns should correspond to 14 psi - the pressure switch says 3.5 psi per turn). Not sure what this is about - given earlier testing showed it cycling and shutting off at 70 psi (I heard the click).

So - I think the pump has a difficult time making pressure after some amount of usage and that is causing excessive energy consumption when that occasion occurs.

I think I must not be understanding the two post pressure switch cut-off though. Based on my initial readings above - 4 full turns doesn't make sense.
 

Reach4

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The pump just stalled at 65 psi while pulling 10 amps.
It looks to me as if you should set your switch to 40/60, and adjust your air precharge to 38. You don't want your pump to be cutting off so close to its deadhead pressure. I understand you would like more pressure, but at this point, for whatever reason, your pump is not up to it. I am not a pro.

Your nut on the little spring should almost take all of the tension off, giving you a 20 psi differential.
 

Valveman

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At 50/70 you probably had the spring in the pressure switch flattened out. Takes a lot more than one round for 3-4 PSI when that happens. That pump just sitting there "stalled" at 65 PSI is wasting 10 amps of current and getting the pump hot in the process.
 

Asheville_jeff

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Great points - I'll definitely drop the top pressure as an interim solution and see what impact that has on my utility bill. Seems like the pump may have intermittent issues pressurizing the tank - but maybe I just tolerate the lower water pressure to see if I can extend it's usable life. I'll need to monitor to see if that continues to drop - either by randomly checking or just looking for power consumption spikes. I noted two days in August that saw double normal power spikes.

Any thoughts on diagnosis from here? I would rather plan an outage than to experience an unexpected water loss, but also don't want to drop the 1-2K of replacement cost if unnecessary.
 
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