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-   -   Well Water, Fluctuating Water Pressure, and the Roller Coaster Pressure Gauge (http://www.diychatroom.com/f7/well-water-fluctuating-water-pressure-roller-coaster-pressure-gauge-48684/)

huuuss 07-12-2009 07:05 AM

Well Water, Fluctuating Water Pressure, and the Roller Coaster Pressure Gauge
 
All - i'm hoping some veterans can help me understand whether i have a problem.

my house is on a well water system. the water pressure fluctuates with use. for instance, when i open a tap and run cold water, i can see the water flow fluctuate. the water flow doesn't go down to zero, but the drop is visually noticeable and then it will increase to the high end and then drop again to the low end - it does this consistently like a cycle.

when i open the tap like mentioned above, the water pressure gauge fluctuates between 38 psi and 58 psi over the course of 10 seconds. so maybe a better way to put it is that the pressure will spike at 58 psi and then over the course of around 5 seconds, the pressure reading will drop to 38 psi, and then over the next 5 seconds steadily rise to 58 psi. this process repeats itself when water is constantly drawn. this makes sense because it reflects the flow at the tap. is this normal? during this pressure fluctuation, i hear a fairly audible click. i'm guessing this click is the pressure switch cycling at the cut on/cut off pressures (or whatever they are called). i don't know. it just seems like it shouldn't have to cycle this frequently as i'm guessing this means the pump is turning on/off that frequently.

any feedback is appreciated. thanks.

Plumbvoltage 07-12-2009 09:19 AM

If you have a bladder type well tank it sounds like either it lost its pressure(2lbs. less than the pump cut in) or the bladder is ruptured. I just recently had my well tank go bad, ruptured bladder. If you have a tire pressure gauge you can check it. Turn off the water and drain off the water pressure to the well tank and check the pressure at the tire valve on top. If your cut in pressure is say 30psi the tank should have 28psi. If water comes out the tire valve the bladder is ruptured.

kb3ca 07-12-2009 09:34 AM

Well Water, Fluctuating Pressure
 
Your pressure tank is water logged, meaning there is little or no air in the top. If it's a bladder tank then the bladder is ruptured and the tank will need to be replaced. If it's the older, bladder-less style you will need to drain the tank, reinsert air into it, then refill with water.

huuuss 07-12-2009 10:57 AM

more info and a question for the vets
 
i have a well-x-trol wx-203, so it is the bladder version. is there any reason (safety?), i shouldn't check the pressure when there is water in the tank? i'm assuming i'll get a faulty air pressure reading because the water is forcing the air into a smaller space, but i want to see if water vapor comes out of the air valve to see if the bladder is the problem. this seems like a simpler check then what i'm assuming i would have to do to check the actual air pressure in the tank, i.e. shut off the pump (and the water heater?), drain the water from the system, and then check the air pressure (and then turn the pump back on to refill the system when finished with the air pressure check).

Daniel Holzman 07-12-2009 11:25 AM

You can check the pressure when there is water in the tank, I did this the other day on my tank, which happens to be the same model you have. Must be a popular tank. The pressure in the tank will vary between the low cutoff, which in my case is 35 pis, and the high cutoff, which is 60 psi on my system, so the pressure you measure will be a function of what point in the cycle you measure it at. However, even if the tank is waterlogged (and I totally agree with previous posters, it sounds like it certainly is), you are still going to get a pressure reading fluctuating between low cutoff and high cutoff due to pump pressure, as long as there is even a small amount of air in the tank. And based on your description, there must be some air in the system, although not much from the sounds of it.

I don't think you are going to see water vapor coming out of the valve, and no, you will not get a faulty reading, it will reflect the pressure of the air in the tank, as long as there is at least some air in the system. The check previously described, i.e. drain the tank, measures the residual pressure in the bladder, which will be listed on your tank (mine is pre-pressurized to 30 psi), is the definitive test, because if the bladder is ruptured, or most of the air has leaked out, you will have less than the design residual pressure when the water is drained. And there is no need to turn off the water heater as long as you do the test quickly, i.e. don't leave an empty water heater for more than a few minutes. But it should take only a minute or so to run the test from the time you drain the system.

kb3ca 07-12-2009 11:34 AM

You can depress the air valve momentarily to see if water comes out but there will be no water present unless the tank is completely full of water and no air. I don't believe this is the case based on what you have described. I believe your bladder is ruptured and water has replaced a large portion of the air and that is why your pump is short cycling. The only way to get an accurate check is to turn off the pump, drain all the water out of the pressure tank and then check the air pressure. It should be 2 pounds lower than the cut-in pressure of your switch. I went through this exact scenario just recently. I had a WellXTrol tank that had a bad bladder, was 19 years old and had some rust at the base. It had probably been bad for some time with a ruptured bladder but like yours it kept working with fluctuating water pressure. If you get a new tank I would recommend getting a 40/60 psi tank and pressure switch. I had a 30/50 psi set-up and I really noticed a nice difference with the higher pressure.

Plumber101 07-12-2009 11:44 AM

As ol' Dan must not be a well man.

First depress the valve core to see if you get water if you do the tank is water logged and needs to be replaced. Sounds like you have but there may be a restriction in the nipple/fitting going into the pressure switch

If you get no water out the valve stem then completely, I'll say this again completely drain the system and check pressure. The pressure has to be set 2 psi below the pressure switch cut in pressure. Also check for a restriction to the pressure switch. Alot of well guys use glav pipe which will corrode and cause a build un in the pipe to the pressure switch. Use brass

If it is a 40/60 switch set at 38 psi
If it is a 30/50 switch set at 28 psi

huuuss 07-12-2009 12:27 PM

thanks for all the feedback folks. much appreciated. ok, based on the above comments, i have one observation that probably will show my ignorance on this stuff, but here it goes. when i knock the side of the tank starting at the bottom moving towards the top, there's a dull thunk until about 1/3 or 40% of the way up at which point the knock turns into kind of a hollow ting - the change in sound happens to coincide with an external rib in the tank. to me, this suggests the transition between where there's water and where there's air in the tank, and possibly, the location of where the bladder is attached to the tank. when i read 'water logged,' i'm assuming the tank would be practically full of water, so does this test suggest that the bladder is still in tact considering the tank seems to be about ~33-40% full of water @ 50 psi?

one more observation. after running the tap and then turning it off, the pressure guage read 50 psi. within 1-2 minutes and without running any water, the pressure is now sitting at a shade above 40 psi. and eventually, the pressure dips enough to trigger the pressure switch. this cycle repeats even when there is no intentionally running water. is this pressure loss normal? do you all still think the bladder could explain this - if this is an issue? or do i have more than 1 issue? i would think that when no water is running, the system is closed between the pump and any of the faucets/toilets/hose bibs/etc., and as a result, would stay at a constant pressure (or close to it) over that time frame. shouldn't the pressure hold for a much longer period of time assuming no water flow, i.e. leaks perhaps?

kb3ca 07-12-2009 03:41 PM

Now you've added another variable to the equation that we didn't know before. The water pressure should not bleed down substantually with no water being drawn. Most systems I've seen have two check valves in them, one at the pressure tank and one on top of the pump. These valves close off the supply line from the pump to prevent water from going back into the well. Sounds like you are leaking water back into the well because one of these is defective.
As far as tapping the side of the tank goes, mine sounded like it had 2/3 water and 1/3 air but the bladder was ruptured.
Based on this new information I would say you need to replace a check valve and hope it isn't the one on top of the pump.
Good luck.

kb3ca 07-12-2009 03:45 PM

One last thought. Make CERTAIN there isn't a toilet leaking somewhere or some other slow leak before you jump into the water pressure problem. That, too, would cause your pressure to bleed down slowly as you indicated.

huuuss 07-12-2009 05:48 PM

k - for the leak input, thanks. i think i'm ok on the pump side because i had shut off the supply to the house side and there was no pressure loss (at least for the 15 minutes or so i kept an eye on it, which was much better than the 4-5 minutes it was taking to drop 10 psi of pressure with the valve supplying the house open), so i'm guessing i do have a leaking toilet to address. i think i'll shut off the house supply tonight, and see if there's any significant pressure loss in the morning (probably a good 8 hours if not more under pressure without the house as a variable) - if not, i'd tend to believe the pump side is ok. i'll check out the toilet situation, and i think i know enough to determine whether the tank's bladder or air pressue is the problem.

thanks all for the feedback. any other thoughts are obviously welcome. i'll post my results as i get a chance to check things off the troubleshooting list you have all helped me develop (though this might be intermittent over the next few weeks).

Plumber101 07-12-2009 06:38 PM

If you turn on the cold water do you get any warm water out? Might take a minute or two with the water running?

Daniel Holzman 07-12-2009 07:10 PM

A leak sufficiently large to explain the rapid pressure loss should certainly be obvious by listening to the main drain in the house in the basement. You would hear water running down it. Not to repeat the obvious, but when you have no faucets open, there should be NO water running down the main drain, if there is it is likely a leaky toilet.

PLAIN O TX 07-12-2009 08:06 PM

I used to live in the country and found the well water table dependend on the baromectric pressure. Could this be a problem?

piercekiltoff 07-12-2009 08:30 PM

No, this problem doesn't relate to atmospheric pressure.

You have two problems.

First, the short cycling is caused by a bad pressure tank or low air pressure in the tank. The model tank you have is a diaphragm tank that should have about 9 gallons of draw down in it given the pressure range you cited - meaning that the pump should fill the tank with 9 gallons of water, then shut off once the system reaches peak pressure. If you can run the tap for only 10 seconds (probably a 2 GPM fixture), you're only getting 1/3 of a gallon draw down out of the tank before the pump turns back on -therefore the tank is the culprit, either by being busted or there's not enough air pressure in the tank.

Second - The 1 to 2 minute pressure loss is caused by a leak, obviously not a HUGE leak, since it's obviously only leaking 1/3 of a gallon over that 1 to 2 minute period. The leak could be in the well casing due to a leak in the drop pipe, or faulty check valves. Or, it could be under ground between the well and the home. Or...it could be in the home.

Unless I missed where you proved that the tank was good, by draining the water, adding air pressure to the tank, and double checking that the diaphragm did in fact hold air pressure with no water pressure in the system, I'd fix problem one first, before your well pump motor goes out.

My two cents as a professional is probably worth a bit more than the governments two cents :)

Oh, and those tanks are popular with the professionals because Amtrol (Well X Trol) invented the diaphragm/bladder tank 50+- years ago, and they provide 5 year manufacturers warranties.

Pierce K
Certified Well Driller (NGWA)


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