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Steven Mactan

Questions About Pressure Tank

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Steven Mactan

I don’t have a lot of experience maintaining pressure tanks, so I have a few basic questions which I hope others can help me with.

 

I have my regulator set so that the pump turns on at approx 5 PSI, and the pump turns off at about 25, PSI. 

 

I’ve noticed that after about a month of normal use that the pump will begin to cycle on and off much more rapidly than it normally does.  Someone told me that this is caused by air building up inside the pressure tank, and that the only was to solve the problem is to drain the tank and to refill it.  Is it normal to have air accumulate inside the tank?

 

When the tank was new, it had a ¾” pipe plug installed on the bottom, but I replaced it with a ball valve in order to avoid having to go under the tank to unscrew the plug al the time.  Could replacing the original pipe plug with a 12” (stainless) nipple and a ball valve cause any problems? 

 

The other day my pump was getting to the point where I usually drain it, but I was distracted, and kept putting it off.  I happen to be standing next to the pump while it was cycling on and off, and during one of its attempts to cycle back on, it appeared to seize, and the pump simply made a humming noise instead of turning.

 

I immediately unplugged the pump, and thought about what to do next.  I decided to open the ball valve to drain the tank. After refilling the tank I plugged it back in, and it still would not turn. I unplugged it again and started looking around for any type of reset button, but I could not find anything. 

 

However, I noticed a small screw (turned out to be a plug) located on the impellor housing. I took the screw out, and I heard a hissing vacuum noise as I removed its housing.  What is this particular screw plug for?  I put the screw plug back in place, and then refilled the tank a second time, mainly because I didn’t know what else to do.

 

My process for refilling the tank goes something like this:

 

1. Unplug electrical power to pressure tank, and close two PVC ball valves separating house from pressure tank.  

2. Open brass ball valve on bottom of tank to let water out.

3. Open brass ball valve located above impellor (photo two) to allow water to drain more quickly.

4. Take a piece of scrap hose and blow air into the upper ball valve to push out all old water.

5. Close lower brass ball valve.

6. Open bypass brass ball valve in photo three, and open two PVC ball valves between house and pressure tank.

7. Observe brass ball valve located above impellor housing, and when water starts bubbling out of valve, close it. (This should mean tank and pump are full?)

8. Start pump and observe pressure gauge.  Make sure that pressure is steadily climbing and that pump is drawing water from storage tank.

When I first got my pressure tank, it leaked everywhere so I replaced the original galvanized fittings with brass and stainless steel fittings.  That is why I have the huge loop of 1” hose, instead of the usual straight dog leg of hose that you would usually find on this type of pressure thank. I simply could not get my new hose into position without kinking, so I decided to make a loop to connect the two ends.  You can see this clearly in both photos one and two.

So I guess that my questions are:

1.  Why did my pump stop turning the other day? 

2.  Could it possibly be due to the fact that it was cycling on and off more quickly than normal, for an extended period of time that particular day? 

3.  Also, is air in the system actually causing my pump to develop a shorter on off cycle over a period of a month or so? 

4.  If so, what causes air to get into the system?  I don’t have any visible leaks,  and I always make sure that there is plenty of water in my storage tank for my pressure tank to draw from (pickup pipe is never exposed).

5.  What is the purpose of the small screw plug located on the impellor housing?

Any advice appreciated.

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philuk

The screw you point out looks to be an air bleed screw,

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Scottiev

 I think the plug in the second picture maybe to prime the system..remove it, fill with water , replace the plug , start the pump.

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lopburi3

The problem is the captive air (you need some) is absorbed into the water over time so there is no air cushion inside the tank so you need to drain and let fill again (so the opposite of what you were told).  Normal water pumps will have an automatic air exchange system to help prevent this from happening and newer models have a bladder inside to keep the water and air apart.

 

I can not imagine using 5 PSI water supply - you might want to consider upgrade of pump/tank to a bit higher pressure if you plan to do anything - otherwise drain and refill tank should get it running again.

 

1.  Overheat shutoff to protect itself.

2.  Yes.

3.  Lack of air is the problem.

4.  You need the air - it provides the pressure - without an air-exchange system you need to recharge by removing water and filling again.

5.  Suspect to add prime water if required.

Edited by lopburi3
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NigelandMJ

I have the same pump, although not connected to a pressure tank, the screw plug is for bleeding/priming the pump. Also, the pressure tank is a hydrophore, so it should contain some air, larger systems have a compressed air connection to the pressure tank for topping up purposes. Air is compressible so provides the pressure and prevents rapid cycling of the pump. I suspect you are filling the tank too full of water.

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lopburi3

The tank is indeed getting too full of water but that is due to it being absorbed into the water over time.  That is why newer pressure tanks have for years had air exchange system and most are now two part with the air separated from the water by a plastic/rubber membrane to prevent the absorption problem.  

muiJlwmBu5TNFJiY83INHtA.jpg

pressure%20tank%20cutaway.JPG

Edited by lopburi3
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RogerDat

Greetings! That is a small tank. I have a 40 L tank set to max 35PSI. Your tank should be rated at 40PSI.

Kick in is 5PSI correct? ( turn on)

kick out set to25 (turn off)

This will cycle very rapidly with a shower, if it is a 40 psi tank, I would go with 35psi.

BUT remember, if you have any GI pipe in the house, it is probably rusted, and will give up the goast when you up the pressure. It happened to me, had to replumb whole house.

Edited by RogerDat
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Steven Mactan

The problem is the captive air (you need some) is absorbed into the water over time so there is no air cushion inside the tank so you need to drain and let fill again (so the opposite of what you were told).  Normal water pumps will have an automatic air exchange system to help prevent this from happening and newer models have a bladder inside to keep the water and air apart.

 

I can not imagine using 5 PSI water supply - you might want to consider upgrade of pump/tank to a bit higher pressure if you plan to do anything - otherwise drain and refill tank should get it running again.

 

1.  Overheat shutoff to protect itself.

2.  Yes.

3.  Lack of air is the problem.

4.  You need the air - it provides the pressure - without an air-exchange system you need to recharge by removing water and filling again.

5.  Suspect to add prime water if required.

So you're saying that the pump NEEDS to have an air cushion to operate properly, and when I was refilling the tank, I was actually replacing air cushion that the pump needs to operate properly?  Wow, what an eye opener! - Also, when water pressure drops to approx 5 - 7 PSI, then my pump starts and boosts it back up to approx 25 - 27 PSI before it shuts off again.  I seem to get good pressure at my taps, so I'm guessing that my average pressure is probably somewhere in the middle. I didn't want to turn the regulator any higher than about 27 PSI, because even the schedule 40 pipe looks pretty flimsy over here. - Thanks for the info.

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Steven Mactan

I have the same pump, although not connected to a pressure tank, the screw plug is for bleeding/priming the pump. Also, the pressure tank is a hydrophore, so it should contain some air, larger systems have a compressed air connection to the pressure tank for topping up purposes. Air is compressible so provides the pressure and prevents rapid cycling of the pump. I suspect you are filling the tank too full of water.

Just want to make sure I'm getting the complete picture, so hope you'll excuse my silly question.  If the electric pump is drawing water from my concrete storage tank, pressurizing it, and then sending it to my metal pressure tank, wouldn't the level inside the tank be determined by the pressure setting of the electric pump?  I'm just asking because I really don't know?  -

 

Also, before I redid all the pipe fittings on this pump, there used to be a 3/4" pipe plug above the impeller housing, where one of my brass ball valves is now located.  In the past I had been using this  fitting for priming, but I guess the smaller screw plug makes more sense. 

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Steven Mactan

Greetings! That is a small tank. I have a 40 L tank set to max 35PSI. Your tank should be rated at 40PSI.

Kick in is 5PSI correct? ( turn on)

kick out set to25 (turn off)

This will cycle very rapidly with a shower, if it is a 40 psi tank, I would go with 35psi.

BUT remember, if you have any GI pipe in the house, it is probably rusted, and will give up the goast when you up the pressure. It happened to me, had to replumb whole house.

The reason why I have the setting so low, is because I don't trust the pipe around my house, which is a combination of PVC and PPR.  When it's working properly it doesn't really cycle that rapidly, and it is just my wife and I living in the house, so it doesn't get that much of a workout.  

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Steven Mactan

The tank is indeed getting too full of water but that is due to it being absorbed into the water over time.  That is why newer pressure tanks have for years had air exchange system and most are now two part with the air separated from the water by a plastic/rubber membrane to prevent the absorption problem.  

muiJlwmBu5TNFJiY83INHtA.jpg

pressure%20tank%20cutaway.JPG

Ah, that makes sense.  So where does the regulator get installed?  Is it on the intake side of the pump, or is it some place else?

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lopburi3

They attach to a hole in the pressure tank to allow new air into the tank when required -  but your tank may not allow so I would not try to DIY.  Just re-prime every few weeks if you do not want to buy a new tank.  Should work fine; as it has in the past.  Pumps are quite good at turning off when overheated so not much damage done when you forget.

 

Plastic pipe should be able to take a lot higher pressure - but some workers cut short a corners and hope for the glue to hold together rather than having a tight fit so can be a problem - not hard to re-do if pipes are on outside as have done in my house here in Bangkok.  Normal pressure runs from low of 35 to 60 PSI without issues.  But as long as you have enough pressure no reason for more - we like the higher pressure for showers.

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Paul

 

 

I’ve noticed that after about a month of normal use that the pump will begin to cycle on and off much more rapidly than it normally does.  Someone told me that this is caused by air building up inside the pressure tank, and that the only was to solve the problem is to drain the tank and to refill it.  Is it normal to have air accumulate inside the tank?

 

I agree with previous statements. Your tank is what we used to call "water logged". It has NO air in it at that point. You NEED air in the tank for it to operate properly.

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colemanlee

 

 

The reason why I have the setting so low, is because I don't trust the pipe around my house, which is a combination of PVC and PPR. When it's working properly it doesn't really cycle that rapidly, and it is just my wife and I living in the house, so it doesn't get that much of a workout.

 

When we moved into our house here I had to completely redo all the pipe, all the old gal pipe was in very bad shape and was in the concrete so I could not get to it...I used schedule 40 pvc for the piping.  Installed a 3/4hp pump on a fairly large bladder tank, several of my Filipino friends warned me off the stainless tanks like you have so I installed (sorry for the cheesy description) a heavy one that was painted a reddish brown color.  The tank cost 8k php where as the stainless ones complete with pump cost about the same as the tank...I also changed from the usual square D pressure switches to one made in Italy (its black plastic cover) that I had never heard of because it seemed in my old place that I was replacing the Square D pressure switch every six months or so.  Strange to me as I have used Square D switches all my life...I think the ones you get here are not the same as in the states.

 

The pressure switch cuts off at 50psi and on at 25 psi and the only trouble I have had with the pressure that high is some of the joints the workers here did have come apart and had to be re glued...not a big deal as I have had to redo much of what they did anyway...I at first set the pump up for both the deep well and city water but found the deep well was producing a lot of sand in the pump so I had to disconnect it and just use city water . 

I do not have a water tank and just use the city water straight to the pump, not ideal but I didnt want to spring for a tank as this will not be our permanent house.

 

I would, if you have funds, just change out the tanks installing a quality bladder tank.  I think your problems will go away...a good quality bladder tank will have a air valve (like on a tire) on the top so you can add air pressure if needed. 

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Paul

 

 

a good quality bladder tank will have a air valve (like on a tire) on the top so you can add air pressure if needed

 

I would make sure I purchased a good quality air pressure gauge to check the pressure on the bladder tank.

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