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cforbes 09-29-2012 02:53 PM

Well Water Pressure Fluctuation
I have searched this extensively and haven't found my issue yet.

My system is:
-a submersable water pump (I know nothing about this)
-UV Lamp
-Water Filter
-Water Softner
-Red Lion Pressure tank

My well water pressure in the home I just purchased fluctuates. So I went ahead and shut off the pump, drained the system, reset the pressure tank pressure to 28 psi, and readjusted the switch for 30-50 psi. When I shower it still fluctuates. I expected the stream of water while showing to be pretty even. So I rechecked all the pressures and when the water pressure is at 30psi the air bladder reads 28psi and when the water pressure is 50 psi the air bladder reads 48-50psi. So I don't think my air bladder is leaking. I decided to time the cycles running a bathroom faucet on cold water only. The pump runs for 16 seconds bringing pressure from 30-50psi and from 50 down to 30psi the pump remains off for 1 minute and 50 seconds. I do notice that when the pump cuts off at 50 psi that the water pressure reading on the gauge drops to 44-46 psi. I don't believe this contributes to the problem.

WHat do I do now to correct this fluctuation issue?

Bondo 09-29-2012 03:22 PM

Ayuh,.... I might be wrong, but I've lived with a well for many, Many years, 'n that's how it works,...

30 psi to 50 psi to 30 psi...

cforbes 09-29-2012 03:49 PM

Yes I understand that. My issue is I can feel an obvious drop in pressure and then a rise, drop, rise, etc.

Daniel Holzman 09-29-2012 03:59 PM

I too have a well which is set to go from 40 psi to 60 psi, which it faithfully does. The amount of time it takes to drop from the high to the low reading is determined by the number of gallons of water released by the tank for a 20 psi drop (known as the drawdown of the tank). For example, a Welltrol 250 has a 15 gallon drawdown, meaning that at 2.5 gpm (typical for a shower), the time between high pressure and low pressure would be about 6 minutes. I am not familiar with your tank specs, but they may be on the tank, or possibly available on line.

If the drawdown on your tank is say 10 gallons, you can measure the flow out of your shower using a 5 gallon bucket, and verify that you have proper drawdown from your tank. As to the pressure fluctuation you notice, that is how a well works, as Bondo noted. The pressure will drop from high to low over the time period determined by the flow and the pressure tank drawdown, and the flow will decrease throughout the period, since the pressure is dropping. Every house I have ever been in with a well exhibits this phenomena.

You can reduce the rate of pressure drop for a given flow by installing a larger drawdown pressure tank. There are also expensive variable speed pumps available which can be used to maintain close to even pressure, but most people do not have them.

cforbes 09-29-2012 05:48 PM

Is the 16 second run time too short for the pump to run?

My pressure tank is 14 gallon and has a 4.3 drawdown at 30-50psi.

Would it be ok to adjust my water pressure to 35-55 or 40-60? I think this would make the pressure drop less noticable since we only notice it during the last part of the drawdown. My parents had a well pump and so did my last house and I've never notice pressure fluctuations before.

Akpsdvan 09-29-2012 06:00 PM

You might try and bypass parts or all of the items after the pressure tank and see how the pressure is, if it is steady then one or more of the treatment items would be the reason of the pressure change.

From what you have listed my first thought would be the filter.. some thing has loaded it up and the flow is getting cut off some how.. but take the items off line and run the checks to see which one is the reason for the season.

daveb1 09-30-2012 09:30 AM

I'm thinking you have a restriction in your system such as a clogging filter or softener. Also is the order you listed your components the same as the order that the water flows?

Daniel Holzman 09-30-2012 09:58 AM

Based on your specifications, your system seems to be running normally. You say you have a 4.3 gallon drawdown over 20 psi. For a 2 gpm shower, that would take about two minutes to draw down, which is what you say you have. As to filling, that takes about 1/4 minute, so your well is putting out about 17 gpm, which sounds about right for a submersible.

You can increase pressure to 40-60 psi range, you need to adjust your tank pressure appropriately (usually set about 2 psi lower than the lower reading, so 38 psi in this case, but check the manufacturer recommendation. This will result in a 33 percent reduction in pressure from high to low, compared to the 40 percent pressure reduction you have now, and you may not notice the difference as much. Or you can get a larger tank, which would provide a longer drawdown period.

I am not clear what the basis of the previous two posters is to conclude there is a restriction in your flow, based on the number you provided I see no evidence of this.

cforbes 09-30-2012 06:39 PM

The order is pump, pressure tank, water softner, filter, uv lamp.

It's the feeling of water pressure in my shower. When the system is pumped up it feels like a nice high pressure shower but when the water pressure drops to about 35 or below it feels so light you wonder if you can rinse the soap off. I'm not used to feeling the difference during drawdown. I never noticed this where I grew up or at my old house.

cforbes 09-30-2012 06:49 PM

Well I was unaware that the water softener could be bypassed so easily. I just checked it and it was already bypassed by the previous owner.

Akpsdvan 09-30-2012 07:24 PM

Then I would be looking at the filter.
Is is one that the filter is changed every x number of months?
When was it changed last?

cforbes 09-30-2012 07:39 PM

Unsure when it was last changed. I've only had the home for less then two months. I'm going to change it tomorrow.

Akpsdvan 09-30-2012 07:47 PM

Change the filter with like micron filter and put the softener back on line.
Or remove the filter and leave the housing with out a filter and put the softener back on line.

AllanJ 10-01-2012 06:52 AM

Most systems use a change in pressure for the switch that turns on the pump to add more water when the pressure tank starts to become empty of water and turns off the pump when the pressure tank is full enough.

If you have a large enough pressure tank (or more than one pressure tank) you can have the turn on pressure value and the turn off pressure value quite close to each other (such as 38/45 or 45/55) and then changes in pressure will be less noticeable. Do not intentionally set these values so close to each other that the pump turns on for only short periods of time.

Unless there are closed valves or check valves, the pressure should be the same everywhere in the system when the pump is off and no one is using water. If a gauge in one part of the system noticeably has to catch up to the gauge in another part of the system after the pump shuts off, look for obstructions in between such as clogged filters. (Can also be caused by pipes with arteriosclerosis but this is harder to locate.)

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