Well pressure tank draw down less than 50% of advertised capacity- Advice needed

Reply

  #1  
Old 12-08-14, 10:08 AM
R
Member
Thread Starter
Join Date: Dec 2014
Location: USA
Posts: 14
Received 0 Votes on 0 Posts
Well pressure tank draw down less than 50% of advertised capacity- Advice needed

Hello. This is my first post. I have been reading around on wells and pressure tanks quite a bit over the last couple of days and have come to the conclusion that I need some help. This seems to be the site with the most useful responses. Thanks in advance for the help.

First, the details. I recently purchased this home so I know very little about the well. The house was built in 1986.
1. Submersible pump, I am not sure of the volume.
2. Well is estimated to be 30 years old. I assume drilled when home was new.
3. Depth unknown
4. Diameter looks to be 4
5. 230v
6. Brand of controls is Pentair 1/2HP SMC
7. Well x troll Wx202 20 gallon. This tank is not new but does not appear to be the original. I am totally guessing it is from the Y2k era. I did not find a date.
8. Pressure setting is 30-50PSI
9. There is a very nice oil filled gauge on the well and I have a digital tire gauge so my pressure reading should be quite accurate.

The issue I am having is with draw down. I am getting about 9 quarts. According to well-x-trol website I should be getting closer to 5-6 gallons. I tested this by letting the well pump up to 50 PSI, opening the utility sink spigot into a bucket and measuring. I hear the 30PSI cut in click right around 9 quarts.

I thought I might have an issue with pressure in the tank so I checked and had 28 PSI in the tank. I also turned the pump off and ran the water to test if the air pressure is correct by watching when the well tank gauge bounces. The water flows out smoothly from 50-28PSI then the gauge bounces and the water stops flowing. Everything seems to be working correctly. I let a bit of air out of the top of the tank and verified that it is not waterlogged.

So, why else would I be seeing a roughly 50% reduction in drawdown. I am guessing that the tank could be waterlogged? That is not something I read about online but seems to be the only explanation I can come up with.

I believe this is unrelated but I also hear a noise when the tank is filling when it is at about the 45-50PSI range. It sounds like a bit of resonance coming up the pipe from the well and it only happens during the last 25% of the tank fill. It is pretty annoying and part of the reason I want this fixed. I am sick of hearing that noise every minute when my wife is showering. The tank is setting on a concrete floor so I can try some type of vibration isolation once I get the drawdown figured out.

Any tips you guys have as to what to check next? I am all ears.

Ryan
 
  #2  
Old 12-08-14, 03:49 PM
V
Vey
Vey is offline
Member
Join Date: Mar 2006
Location: Mid-Florida
Posts: 1,343
Received 0 Votes on 0 Posts
For a new homeowner and a first-time poster, you are doing very well.

We call this "short cycling" which is sometimes due to water logging. I would try resetting the tank. We have instructions on how to do that in the sticky. http://www.doityourself.com/forum/we...well-info.html

Hope your bladder isn't busted, but if it is, you might want a larger tank. You want your pump to run for at least a minute when it is filling your tank.
 
  #3  
Old 12-08-14, 08:05 PM
R
Member
Thread Starter
Join Date: Dec 2014
Location: USA
Posts: 14
Received 0 Votes on 0 Posts
I read through the sticky and have the following update. I am referring to the section called "instructions to pressurize a water tank that has a bladder in it." I turned off the well and opened the sink spigot until it was depressurized. I then turned off the main water valve to the house which is betweeen the well pressure tank and the house. I thought this would prevent the water from the hosue from draining back on me when I pulled the plug to drain the tank. As soon I tuned off the valve pressure started building back up again. This did not make any sense to me unless air was pushing through the bladder and back into my pipes. I opened the valve to the house to let out the pressure and it happened again a few times. Eventually it stopped and I pulled the plug to "drain the tank."

With the plug pulled I tested the air in the tank. It is right at 29 PSI. I then shoot and knocked on the tank it is dull sounding for about the bottom 1/3 and when I shake it there is water in it. The water sounds like it is about 3/4 of the way to the top. The strange thing is, it is still holding pressure. What gives? Do I have a pin hole in my bladder that is leaking slow? I left the pump off and the valve to the house open so if there is pressure leaking out of the tank I should get some air gurgle or something to clue me in.

How do I get the water out of the tank? can I take it out, pull the valve stem and flip it upside down? The pipes are pretty corroded so I may take it apart and not even want to put it back together without having a new tank in there. Time is worth something ya know. Plus, I dont want a leaking mess.

I was already pricing the tanks at Menard on my way home. Any more tips or tricks before I yank the tank and start over? I have plenty of room in there for a larger tank.
 
  #4  
Old 12-09-14, 07:29 AM
V
Vey
Vey is offline
Member
Join Date: Mar 2006
Location: Mid-Florida
Posts: 1,343
Received 0 Votes on 0 Posts
All the water is supposed to be in the bladder or diaphragm. All the air is supposed to be the the tank. If the twain are meeting, then you have a hole in the bladder. Nothing to do, but replace it.

I don't know much about tanks with bladders since I've never had one. But I do know why they put bladders in tanks and that is to keep the water and air separated. It's said here that the new diaphragms are better than the old bladders since they don't rub the sides and develop holes that way.
 
  #5  
Old 12-09-14, 04:04 PM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,360
Received 118 Votes on 109 Posts
The purpose of a bladder or diaphragm in the pressure tank is to keep the air cushion from being gradually absorbed by the water and therefore requiring resetting of the tank pressure periodically.

When water gets on the wrong side of the bladder or diaphragm, the tank will still function although the less air remaining in the tank, the shorter the pump cycles.

When water gets on the wrong side of the bladder, often the bladder herniates into the outlet preventing full emptying of the water from the tank. There is no easy way to fix this and the standard solution is to replace the entire pressure tank.

A larger or second pressure tank causes no harm and will in fact improve the system operation.
 
  #6  
Old 12-10-14, 09:52 AM
R
Member
Thread Starter
Join Date: Dec 2014
Location: USA
Posts: 14
Received 0 Votes on 0 Posts
Thanks to all. I will be replacing the pressure tank. It seems like there are some pretty reasonable prices available on 30 gallon tanks and they will fit in my space quite easily. I will report back here once it is finished to let you all know the outcome. I will also try to get some photos.
 
  #7  
Old 12-10-14, 03:58 PM
R
Member
Thread Starter
Join Date: Dec 2014
Location: USA
Posts: 14
Received 0 Votes on 0 Posts
Hi all. I have an additional question around GPM and tank size. I was just doing some additional tests and calculated the following data. I set the PSI to 30-60 to try and save on some pump cycles but it only got me about an extra 2 quarts of drawdown.

So I now have 3 gallons of drawdown measured via bucket in the sink between cycles and the pump fills the tank back up in 15 seconds. If I multiply the 3*4 I get 12 GPM. That seems like an extremely large pump for a house with only 1/2 HP. I have heard you want the pump to run at least a minute, for me that is going to be 12 gallons of drawdown and a giant tank. If I put in a 30 gallon tank with 7+ gallons of drawdown my pump is only going to run from 30-40 seconds a cycle.

I am thinking of just getting a 30 gallon tank and going with it because that is already 50% larger than what I have and it seems reasonable for my 2000 square foot house with a family of 3. But I still wanted to run it by others with more experience.

Thanks again for the help.
 
  #8  
Old 12-10-14, 04:13 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,157
Received 69 Votes on 61 Posts
If your not getting water out the schrader valve then the tank would seem fin IMO...

To check the air pressure in the tank you need to empty the tank completely and leave the drain valve open at the tank...

Is your pressure gauge actually accurate?

You said you have 28 psi in the tank. did you add air to get it to 28 psi? If not I find it hard to believe the tank still has proper air charge. Bladders lose 2 psi a year roughly..

Also a deep sub pump like yours the pressure switch should be set to 40-40...
 
  #9  
Old 12-10-14, 04:17 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,157
Received 69 Votes on 61 Posts
I also turned the pump off and ran the water to test if the air pressure is correct by watching when the well tank gauge bounces. The water flows out smoothly from 50-28PSI then the gauge bounces and the water stops flowing.
When you did this the gauge should have went to 0 after 28psi. Thats normal as the tank should have been empty and the bladder then collapses and blocks the outlet...

This also happens when there is too much air in the tank. You may be taking a shower and suddenly lose water pressure. Then it gradually bulds up as to pump cathes up..

How is the flow when showering? Steady? Up and down, up and down with flow?
 
  #10  
Old 12-10-14, 04:24 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,157
Received 69 Votes on 61 Posts
Look at your pentair control or somewhere on a tag that states what pump you have down in the well...

If its a 12gpm pump you should have a wx250 per x trol...
 
  #11  
Old 12-10-14, 04:26 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 18,157
Received 69 Votes on 61 Posts
But regardless you should get 6 gallons of draw down from that tank before the pump kicks on... And if the bladder was shot the pump would be cycling rapidly on, off, on, off.
 
  #12  
Old 12-10-14, 06:13 PM
V
Vey
Vey is offline
Member
Join Date: Mar 2006
Location: Mid-Florida
Posts: 1,343
Received 0 Votes on 0 Posts
I'm a 40/60 man myself. I want the shower water to really go deep into my hair. But I also realize that 60 = less water in the tank which means I like at least a 50 gallon tank and that some pumps just lack the ooomph to get the tank to 60 and hold it there after the tank is exhausted and it is on pump pressure only.

Five or six gallons of water is just not enough of a reserve for me.
 
  #13  
Old 12-10-14, 06:31 PM
R
Member
Thread Starter
Join Date: Dec 2014
Location: USA
Posts: 14
Received 0 Votes on 0 Posts
I am getting constant flow when showering or using the water. There is no other indication of a problem other than the short cycling.

I am quite sure my gauge is accurate. I have about 5 of them and they usually all read pretty close. The tank had 30.5 PSI in it when I first put my gauge on it. I can't say the last time it was charged as I just purchased the house in November. I took some air out and put some air back in, at no time did water come out of the schrader valve. However, I never let all of the air out. I could do this and see if the bladder pushes water to the top of the tank and out of the schrader. That may be another good test. I just dont want to put that strain on the bladder, is it made to hold all of the water pressure with no air supporting it from the top? I know there is water about 3/4 of the way to the top of the tank because I can hear it when I shake the tank when the drain plug is pulled.

When I ran the water out of the tank the water pressure dropped to 28 PSI, bounced and then the gauge dropped to zero and the flow stopped.

My pump control does not seem to list a GPM. All I know is 230V and 1/2 HP.
 
  #14  
Old 12-10-14, 06:32 PM
Z
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 3,315
Received 35 Votes on 34 Posts
I want the shower water to really go deep into my hair.
lol....lol.. Good one!.......
 
  #15  
Old 12-13-14, 01:04 PM
R
Member
Thread Starter
Join Date: Dec 2014
Location: USA
Posts: 14
Received 0 Votes on 0 Posts
This is just a follow up to close out this thread. I went ahead an installed a 44 gallon tank last night. I didn't measure quite enough before buying the tank so I had to remove a copper pipe and put it back in front of my tank once it was positioned. Hopefully, it is not needing to come out again for a while.

From start to finish it took me about 2.5 hours. It took another hour to shop and another hour to clean up, including repainting the floor.

My old tank was a boat anchor. Jammed full of something, water, dirt, I don't know but the water that is coming out of there smells something terrible. It wouldn't drain on it's own even with the valve stem pulled and sitting on its side. So i popped a few holes in it with a drill and it is draining in the laundry room. Albeit the water is not coming out the top or the bottom but out of the middle. Who knows... why.

The total bill came to $256 of which $229 was the tank. Menard's had by far the best price I could find on tanks. With the exception of Amazon, and I didn't want to get online if I was going bigger due to my inability to measure. I reused a lot of the old pies. They were galvanized and in very good condition. I didn't even bother replacing the pressure switch or gauge. That might come back to bite me but for now I have 13 gallons of draw down and my pump runs for about 70 seconds to fill up the tank.

My water smells much better, I think I was brewing some cooties in that tank.

Thanks to all for the help.
 
  #16  
Old 12-14-14, 11:37 AM
O
Member
Join Date: Dec 2006
Location: Canada
Posts: 687
Received 2 Votes on 2 Posts
13 gallons of water from a 44 gallon tank is as close to perfect as one can get. Good job.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: