Well Pressure Tank cycles pretty quicly

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Old 12-22-16, 02:52 PM
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Well Pressure Tank cycles pretty quicly

Hello - I am a new member posting on an issue I think I might have. It is a 42 gallon pneumatic tank from from Larson - Becker company built in 12/1967!! It is tested to 150# and designed for working pressure of 75#.

So the problem, I think I'm having, is that the tank is set at 35-55 and kicks in appropriately at 35 and shuts off at 55 and will hold. However it cycles 2-4 times like this when I flush the toilet once. I feel like it would generally cycle on and fill the tank and the pump would come on and cycle far less. My water pressure is fine and all is working but just seems like the pump is being kicked in quickly - pressure dial goes from 35 to 55 in a couple of second and then from 55 to 35 in less than 5 seconds.

I guess the question is how much water, if working properly, should I get out of a 42 gallon tank set at 55psi as it drops down to 35psi???

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Old 12-22-16, 03:42 PM
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It sounds like your pressure tank is shot/water logged. You could replace your old tank with a modern bladder style. Or, you can try adding air to your existing tank which should get it working for a while.
 
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Old 12-22-16, 04:39 PM
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Thank you for the reply Pilot Dane

Is this where I'd put air in? With a compressor?
 
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Old 12-22-16, 06:38 PM
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I have a tank like that, and to add air (about once a year), I shut off the pump while I drain the water system as much possible through the normal appliances, and then maybe 5 or 10 gallons more from the bottom of the tank itself (which removes miscellaneous debris !), and then I re-activate the pump.

That seems to increase the time between on/off cycles because there's so much more of a compressed air-cushion to expand before the low-limit is hit.
 
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Old 12-22-16, 08:37 PM
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Vermont - thank you for the comment. I'm up for giving that a whirl. TO be clear.
1) Cut power to pump and pressure tank
2) Run as much water from faucet as possible.
3) Remove drain plug on tank to let out another 5-10 gallons of water.
4) Re install drain plug
5) Repower the pump and tank

???
 
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Old 12-23-16, 04:56 AM
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Yes; that's just about all I do . . . . plus remember to close up any faucets I opened up in the living quarters !

After you're finished, warn your occupants to open the faucets slowly because they'll be sputtering as any trapped air will be escaping . . . . and with it will come any debris which may have been dislodged from inside the piping. It's probably a good time to clean any strainer/screens at the ends of your faucets.

Your system may have a device on it (like a Brady Air Volumn Control) which is intended to automatically replenish the air; but it may be clogged, so this procedure ought to start you out fresh. Your pump will compress the air which was allowed to fill the tank, and because you draw your water from near the bottom of the tank, the bulk of the air will stay in the tank at the top.

My "old" galvanized tank was already considered an antique in 1987 when I bought this farm, and I was told I should plan on replacing it soon, so I'm still in the planning stage, and I shouldn't be surprised when then day comes that I have to do so . . . . but it hasn't come yet.
 

Last edited by Vermont; 12-23-16 at 06:14 AM. Reason: Added name of Air Volumn Control
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Old 12-23-16, 08:26 AM
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Just another after-thought: when you have stopped getting water from your taps upstairs, you may want to loosen, or temporalily remove, the Schrader Valve (aka a Tire Air Valve) lwhich is located just below your pressure gauge on the side of the tank.

The valve stem tool for doing this is currently screwed onto the stem itself (handy), and this will break the vacuum while you draw off that additional 5 to 10 gallons of water. After you've drawn that water, you can tighten the core of the valve back up, and replace the stem tool as a valve cover.

Your tank is so tall, you'd be there for a Month of Sundays (IOW - a long time) trying to get that amount of water out of the tank without first breaking the vacuum and letting air in from above.
 
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Old 12-23-16, 09:03 AM
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I had the same exact tank in my old store. It never held the air very long. I used to keep a tank of air next to it and gave it a shot every other week. I didn't measure.... just added fifteen seconds worth.
 
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Old 12-24-16, 09:45 AM
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Thank you for the advice

Ok - I think I'm ready to give this a shot but wanted to ask one more question. I plan on removing the lower of the two drain plugs on the tank to remove the water. What should I have ready to coat the plug for resealing it when I'm ready to put it back in? Plumbers tape, some type of coating?

Thanks!

Also - on adding air to the tank through the schrader valve. I'd expect the best way would be when the pressure is towards to low end (say 40psi) to turn the power off to the system and pump air into the system until I hit the high point (55psi as set on the switch now).

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Old 12-24-16, 10:12 AM
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Regarding the "Plug", I just smear some non-toxic Pipe Dope, or Plumbers' Thread Compound on the threads to make a good seal . . . . others may use some Teflon Tape, especially if it looks like the threads are likely to rust together. I go into this port often enough that rusting together hasn't been an issue.

On "adding air", I don't. Opening up the tank and draining excessive water allows air to enter naturally and arrive at my normal atmospheric pressure before I seal it up and re-activate the pump . . . . so I don't have to get involved in any supplemental adding of air.

The air gets pressurized to the high limit (or cut-out) pressure through the action of the water pump . . . . when I re-activate it.

I'm not Clark Kent, so I can't see inside the tank; but I envision that my procedure results in a tank that's about 80-90% filled with water and 10-20% filled with compressed air (at the top).
 

Last edited by Vermont; 12-24-16 at 10:29 AM.
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Old 12-24-16, 11:10 AM
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Should I just use this valve?



So as I was taking out the bottom plug I noticed the drain valve off to the right. I guess I should just use this with the Schrader valve removed to flush out the 5 - 10 gallons?

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Old 12-24-16, 12:12 PM
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That looks like it will work . . . . if it isn't tooooo tender !

If you haven't opened it before, it would be interesting to use a white or clear container to examine what comes out along with the water ?

Don't be surprised if it drips afterwards . . . . you may need to replace an old brittle washer in that valve.
 
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Old 12-24-16, 07:26 PM
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For repressurizing a non-bladder tank, it is safe to err by putting in a little too much air. This system is very forgiving of this and will rebalance itself fairly quickly although in the form of sputtering air out of some faucets.

Note: If you draw water from a non-bladder pressure tank system faster than the pump can deliver the water for a prolonged period of time then you will lose the pressure tank charge. But this will be remedied by doing another recharge.
 
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Old 12-26-16, 12:47 PM
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What about the pressure range?

So I took 5 - 10 gallons out and then restarted everything. The cycle to pump in now last more than just 2 seconds going from 35 to 55 and seems to hold better as it draws down. I didn't get a lot of nasty stuff from the gallons I took from the tank but did through the faucets after I restarted the system up - dark muddy water.

My final question on the topic is why is the range 20 psi? My system was set at 30-50 cut on/off points and the switch originally was set at 40-60 cut/on off. I decided to put at 35-55 for no other reason that it is inbetween. Now if the reason for the tank is that it is to relive the pump from turning on and off repeatedly then I'd think you'd want the maximum interval that your tank would allow without compromising water pressure. My tank says it's good for a working pressure of 75#. Why wouldn't I want to set the switch points to say 25-75? This would put a range of 50psi from when the pump fills the tank. Wouldn't the pump kick on less frequently and pump more per cycle that it is on?

Thanks for everyone's help and advice - I really appreciate it.
 
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Old 12-26-16, 02:27 PM
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I'm glad you were able to complete this task; the brown water you experienced is probably just a few molecules of mineral deposits from the insides of the pipes in your house . . . it will quickly dissipate with the flow of water.

Regarding your other questions , , , , I DON'T KNOW. I'm just a Real Estate Broker and don't know squat about plumbing theory. Maybe a real Plumber can chime in, before moving to the boonies, I didn't even know how to spell plumBer !

But I suspect that you're correct in postulating that the 20 PSI differential is to ease the burden on the pump. I also think that too great a differential would lead to some discomfort for the occupants who've come to expect a certain water pressure to be present at the spigot and shower head, and too much variability would create objections.

You could experiment with a wider range. That would be just the opposite of what I have done in the 1832 dwelling that I currently own (it didn't have indoor plumbing until the early 1950's. After having had the original Myers 1909 Piston Pump die on me, my initial Centrifugal Pump here was only ⅓ HP on a 30/50 Controller and that pump couldn't quite achieve 50 PSI; it would just run and run and run endlessly, never getting to the upper limit.

And when I experimented with a 20/40 Controller, that pressure wouldn't provide a comfortable shower in our 2nd Floor Bath, so I had to install a 30/50 to make something like a 30/46 PSI Controller (a 16 pound differential).

Recently, I installed a HP Jet Pump and a fancy new 40/60 Controller, so we're living high these days (water pressure wise) !

Most Controllers (from Square D) only allow one range of cut-in/cut-out differentials, so they're 20/40, 30/50, or 40/60. It sounds like your switch has infinite settings that allow you to consider 25/75 PSI ?

But remember that while the tank (originally) could originally withstand 75 PSI, aging may have enfeebled it a bit . . . . and despite the tank being able to withstand that pressure, your pump may have difficulty achieving it. And your Pipes; how tender are those pipes ? Nonetheless, it's a good place to get you some cheap entertainment . . . . if that kind of thing rings your chimes !

Good Luck . . . . and remember, "If it ain't broken . . . . then don't break it !"
 
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Old 12-26-16, 08:31 PM
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Pump turn on at about 2/3 of pump turn off (such as 35/55 or 40/60) is quite common. If pump turn on is a much higher percentage (such as 35/40 or 50/60) then the pump will come on again when less water has come out of the pressure tank. If pump turn on is a much lower percentage (such as 25/75) then you will think and feel that the water is getting sluggish during your shower or while hand washing dishes etc.

With or without a bladder in the pressure tank it is usually necessary to add air to the pressure tank to get all the air out. For best performance the air cushion in the pressure tank should be as big as possible which means that all of the air should be out when the system pressure is slightly less than the pump turn on pressure. To achieve that you will want the system depressurized with a cold faucet open while you try to get the expansion tank up to pump turn on pressure minus two PSI. For a non-bladder tank the faucet will spit solid air before you can get the pressure up. In that case turn off the faucet and then keep adding air to the pressure tank until you get to pump turn on pressure minus two.
 

Last edited by AllanJ; 12-26-16 at 08:58 PM.
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Old 12-26-16, 09:10 PM
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(QUOTE) On "adding air", I don't. Opening up the tank and draining excessive water allows air to enter naturally and arrive at my normal atmospheric pressure before I seal it up and re-activate the pump . . . . so I don't have to get involved in any supplemental adding of air.

The air gets pressurized to the high limit (or cut-out) pressure through the action of the water pump . . . . when I re-activate it.

I'm not Clark Kent, so I can't see inside the tank; but I envision that my procedure results in a tank that's about 80-90% filled with water and 10-20% filled with compressed air (at the top). (END QUOTE)

This setting is incorrect. The 10-20% compressed air cushion at the top will not have enough oomph to get more than a couple of gallons out over a couple of seconds before it expands and its pressure drops enough to force the pump to restart.
 
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Old 12-26-16, 09:29 PM
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ON MY POST 2 POSTS UP CHANGE "ALL THE AIR SHOULD BE OUT" TO "ALL THE WATER SHOULD BE OUT".

Forum would not let me edit.
 
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Old 12-27-16, 05:52 AM
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It's true in working with a "non-bladder tank", that the faucets will spit some air until the tank outlet is submerged (which is almost immediately). Luckily, they position the outlet at the lowest point in these tanks . . . . well below the inlets.

I only know that allowing "ALL" of the atmospheric air captured while the tank is close to empty, and then activating the pump to fill the tank with water, results in a bubble of air at the top, and when the incoming water (35F) significantly colder than basement room temperature (55F), I can see the internal water level rising as represented by a horizontal line of condensation on the side of the tank. So without being Clark Kent, that line of condensation serves to give me insight enough to surmise what's going on inside the tank.

And that line of condensation is about 10-15% below the top of my tank at the point my pump reaches the high limit or cut-out pressure; and I seem to be getting plenty of water (10-20 gallons) before the pump reaches the low limit and is reactivated. It doesn't short cycle (at least initially) until a substantial portion of my air cushion has been absorbed, . . . . and then I engage in this procedure again, about once a year. Works for me !
 
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Old 12-27-16, 07:29 PM
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AllanJ thank you for the additional methodology. I think they're both good methods to getting a better air pressure within the tank. I am interested in the adding air method because I'd assume it's a more scientific process.

When I did run out the pressure and then began to draw water out of the tank I felt that some of the water was drawing back down to the basement from upstairs so maybe a gallon or 2 of what I drew out was water from the pipes vs the tank.

Vermont - my switch on top of the tank is a Square D that came set at 40/60 according to the label under the lid. When I watched the tank cycle it was set at 30-50 - possibly by the former homeowner or prior service person. My house has half inch copper piping and haven't had any issues on the water delivery side. I watched a youtube video on setting the cut on and off amounts as well as the gap between the two - same general directions are on the underside of the switch cover. When depressurizing the tank/system I didn't see a noticeable drop off in pressure at the sink until I got to about 15 psi.

AllanJ - in your process would this seem to be what you were outlining with actual steps?
1) Unpressurize the system by turning the pump/switch power off and then running water out of delivery pipes/faucets from lowest point in house.
2) If switch is set at 40/60 then I'd want to increase pressure in tank via compressor until it gets to 38psi (cut on point minus 2)
 
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Old 12-28-16, 05:56 AM
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Yes, what you said is a correct outline of the process: (1) Unpressurize the system ... (2) If switch is set at ...

An idiosyncrasy worth noting: It is possible to siphon water out of water heaters during the process. To prevent self destruction by running with air in the tank or heat exchanger, water heaters (tank or tankless) should have the heat turned off during the pressure tank setting process and a hot faucet for each water heater run for a minute when all done and with the pump turned back on to be sure all air pockets in the hot water system and heater are expelled before turning the heat back on.

You will still get acceptable final pressurizing if you open faucets one or two floors above the pressure tank for depressurizing. This way less water will fall down from upstairs during the depressurizing step. Do not use hot faucets for depressurizing.
 
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Old 12-28-16, 09:54 AM
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Ok -
1) Turn off hot water heater
2) Turn off pump/pressure switch
3) Depressurize system by opening Cold Faucet until water stops.
4) Leave Cold faucet open or close?
5) Using compressor fill tank with air until you reach 2psi less than cut on switch.
6) Close faucet IF left open in #4
7) Turn on Pump/Switch
8) Let system pressurize to cutoff.
9) Cycle cold water through faucets
10) Cycle hot water through faucets for 1 minute
11) Turn on Hot Water Heater
 
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Old 12-28-16, 08:46 PM
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(4) Leave cold faucet open or closed?

Leave it open while you start using the compressor. Wait for additional water to come out of the cold faucet.
A bladder pressure tank will build up pressure after the faucet stops letting out water. A non-bladder tank will not in which case you should close the cold faucet when you observe a continuous air flow out of that faucet.
 
 

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