Bladder tank empty, pressure increases

Users who are viewing this thread

Hilliker

New Member
Messages
8
Reaction score
1
Points
3
Location
Michigan
I noticed a loss of pressure in my house when multiple fixtures/appliances were being used simultaneously.

I checked to ensure pump was operating as expected, pressure is set 40/60. If the shower is running and a toilet is flushed the system pressure drops quickly until the pump kicks on at the cut on of 40psi. I checked the bladder tank pressure when the cut off hit 60 and pump was off. The bladder tank showed 60+ psi (?!) I beleive it should be at 38.

I shut everything off and disconnected the tank and there was only a trickle of water that came out. Not waterlogged, it was empty. I reconnected, bled air out of the valve on top until 38. Turned everything back on, tested, but the same symptoms persisted (pressure drops quickly when shower and toilet used until pump kicks on). I checked the bladder tank pressure and it was back at 60psi. Disconnected tank again and checked inlet pipe for any blockages, but found none.

I am scratching my head because at some point shouldnt the bladder fill with water when the air is removed? How would air get back in to continue pressurizing? The volume of air that can be pressurized should be decreasing as I bleed it out. I'm over my head at this point....

I have searched the forums and others online, but I cannot find a thread with similar symptoms.

I am going to replace the tank, but I thought I would see if there are other possible causes I should investigate.
 

Reach4

Well-Known Member
Messages
35,121
Reaction score
3,581
Points
113
Location
IL
I checked to ensure pump was operating as expected, pressure is set 40/60. If the shower is running and a toilet is flushed the system pressure drops quickly until the pump kicks on at the cut on of 40psi. I checked the bladder tank pressure when the cut off hit 60 and pump was off. The bladder tank showed 60+ psi (?!) I beleive it should be at 38.
Air precharge should be set and measured when the water pressure is close to zero. If the water pressure is higher than the air precharge, the air pressure gauge will always read close to the water pressure.
 

Hilliker

New Member
Messages
8
Reaction score
1
Points
3
Location
Michigan
Air precharge should be set and measured when the water pressure is close to zero. If the water pressure is higher than the air precharge, the air pressure gauge will always read close to the water pressure.

Thank you for that. When I disconnected the tank I set it to 38psi. I left that part out, sorry. I will check again at zero pressure.

What could cause the tank to not fill? How much water should be expected in the tank when I disconnect it? Is this the drawdown amount? I am obviously a DIY and a plumbing novice, but I did find the calculation for drawdown and I expected it to be approximately 10gal.
 

Reach4

Well-Known Member
Messages
35,121
Reaction score
3,581
Points
113
Location
IL
noticed a loss of pressure in my house when multiple fixtures/appliances were being used simultaneously.
That could be a problem with a clogged filter, or other device, limiting the flow.

Thank you for that. When I disconnected the tank I set it to 38psi. I left that part out, sorry. I will check again at zero pressure.
Good.

What could cause the tank to not fill?
Even tho the pressure goes to 60? How quickly does the pressure rise to 60? If fast, the problem is almost surely the pressure tank.

Suppose the area above the diaphragm was almost full of water.

What could cause the tank to not fill? How much water should be expected in the tank when I disconnect it?
zero.
At that point, the tank should be fairly light. If you knock on the tank, it should sound hollow. If your tank is heavy, it is bad.
 

Hilliker

New Member
Messages
8
Reaction score
1
Points
3
Location
Michigan
Got it. Thank you so much for taking the time to answer my questions. I realize some of them are general and could be found by searching.

The pressure rises quickly to 60psi. It is almost as if I do not have a tank and the pump just kicks on and runs when water is being used. This is why I suspected the tank as the likely culprit. It is less than a year old, so I was thinking there may be another explanation.
 

Bannerman

Well-Known Member
Messages
4,297
Reaction score
595
Points
113
Location
Ontario, Canada
The drawdown amount is the water quantity that will enter the tank between 40 to 60 psi which is the same amount to exit between 60-40 psi. The 38 psi air pre-charge will allow only a small amount of water to enter the tank between 38-40 psi. The precharge air is held within a separate chamber from the water chamber, separated by a rubber bladder or diaphragm. Water entering the tank will press against the bladder which will further compress the air. As more water enters, the air will be further compressed which is why the air and water pressures will be identical when the system pressure is above 40 psi.

As you have verified the 38 psi air precharge remains when the tank is disconnected and also confirmed no water is remaining in the tank when drained, it then appears the tank is functioning properly.

The pressure tank, should be large enough that the well pump will run at minimum, 60 seconds to restore the drawdown pressure from 40 to 60 psi. This could be tested by turning on a faucet until the pump turns on, then close the faucet and time how long before the pump shuts off. If less than 60 seconds, that will indicate the pressure tank is too small. Some pump experts prefer a larger tank, so the pump will operate at minimum 120 seconds. Longer minimum pump operation will extend pump life whereas short, frequent pump cycles will overheat a pump and reduce its lifespan.
 
Last edited:

Valveman

Cary Austin
Staff member
Messages
13,243
Reaction score
920
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
A 44 gallon size pressure tank will hold 10 gallons with a 40/60 switch setting. Is the pump still cycling on/off between 40 and 60 over and over while using water and experiencing low pressure at the faucets?

 

Hilliker

New Member
Messages
8
Reaction score
1
Points
3
Location
Michigan
A 44 gallon size pressure tank will hold 10 gallons with a 40/60 switch setting. Is the pump still cycling on/off between 40 and 60 over and over while using water and experiencing low pressure at the faucets?

Yes. That is exactly what it is doing. I think its referred to as short cycling. It only takes 33 seconds for the pump to pressurize from 40 to 60. I understand this is very bad for the pump.

Background info:
In May 2019 the existing 20gal tank failed because the inlet rusted over time. I replaced with the exact size tank and have had no issues with pressure or short cycling. There was a sudden change this week that I am trying to diagnose. I turned the water softener to bypass to eliminate that. I have a whole house filter that was just changed last month.
 

Hilliker

New Member
Messages
8
Reaction score
1
Points
3
Location
Michigan
Also I realize now that the title of my post is exactly the expected behavior for a bladder tank, so I can post my original issue to a new thread if that would be more appropriate. I want to keep the moderators happy :D
 

Valveman

Cary Austin
Staff member
Messages
13,243
Reaction score
920
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
A 20 gallon tank only holds 5 gallons of water. So, 33 seconds to fill with a 10 GPM pump sounds right. Can you get 5 gallons out as the pressure drops from 60 to 40? If so your tank is good.
 

Hilliker

New Member
Messages
8
Reaction score
1
Points
3
Location
Michigan
A 20 gallon tank only holds 5 gallons of water. So, 33 seconds to fill with a 10 GPM pump sounds right. Can you get 5 gallons out as the pressure drops from 60 to 40? If so your tank is good.

I believe so, but I will test and confirm.

If the tank is in fact good, what should I be looking at to account for the sudden change in pressure at the fixtures? There are no apparent leaks. With all faucets/fixtures off, the pressure at the tank is maintained at 60.
 

Valveman

Cary Austin
Staff member
Messages
13,243
Reaction score
920
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
Rapid cycling because of a bad tank can make the pressure a little worse. But it is still cycling between 40 and 60, the pressure is the same. You may have a restriction like a clogged filter or stuck check valve as well as a bad tank. If the tank bladder is bad already, it was probably going up and down too much from the pump cycling.
 

Hilliker

New Member
Messages
8
Reaction score
1
Points
3
Location
Michigan
The tank was less than a year old but with a 5yr manufacturer warranty, so menards would replace it with a new one. I'm back in business with great water pressure, and little expense. Thank you all so much for taking the time to reply and provide great information and assistance. In these crazy times money is tight, so I'm having to do a lot of things myself, but I would have been stuck without you and this forum. I am very grateful and thankful. Cheers to you, my water supply is fixed and my woman is happy. Life is good :D
 

Valveman

Cary Austin
Staff member
Messages
13,243
Reaction score
920
Points
113
Location
Lubbock, Texas
Website
cyclestopvalves.com
The tank was less than a year old but with a 5yr manufacturer warranty, so menards would replace it with a new one. I'm back in business with great water pressure, and little expense. Thank you all so much for taking the time to reply and provide great information and assistance. In these crazy times money is tight, so I'm having to do a lot of things myself, but I would have been stuck without you and this forum. I am very grateful and thankful. Cheers to you, my water supply is fixed and my woman is happy. Life is good :D

Yeah well if the tank bladder was already bad you are probably cycling the pump too much and it will happen again. A bad tank or pressure switch is just the first clue you are cycling the pump too much and you will also soon need a new pump.
 

Hilliker

New Member
Messages
8
Reaction score
1
Points
3
Location
Michigan
So, installing a cycle stop valve, to extend whatever pump life I have left , would be worthwhile?
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks