Pressure Tank Not Filling With Water

[siermac]

Hello all,

First time posting in here, hoping for some help before I have to spend hundreds of dollars getting someone to come out and look at it. A few years ago we built an addition to my in-laws place for us to live in. To help with the additional people now living on the property, and the desire to have more of a reserve during outages, we added another pressure tank over in the new addition. The main house has a ~30gal tank, and addition has a 119gal tank. This past year we've noticed that when the power goes out, we have little to no water reserve. We're talking flush a low flow toilet one and brush your teeth and that's it for water. The configuration is:

- Well feeds into main house where the pressure switch is located.
- Main house has a 26gal pressure tank.
- After the tank the line tees off with one pipe going to the rest of the plumbing in the main house, and the other pipe heading back outside and over to the addition . Its roughly 50 feet between the two tanks, and the new one for the addition is maybe 3 or 4 feet higher since the main house one is in a crawl space and the new one isn't.
- Line comes into the addition to another tee, with one side going to a 119gal pressure tank, and the other side heading towards the filters and the rest of the plumbing. (see picture - black pipe just to the right of the tank is the line coming from the main house)
- Pressure switch is set to 42/60 in the main house (yes 42, can't remember why he wanted it set like that). We have synchronized the pressures in the tanks multiple times. I just readjusted the addition side so that I get 39-40PSI on the tank.
- Pressure gauge right before the 119gal tank (says 40PSI), another in between two filters(top right of pic and says 42PSI), one after the last filter, and a few others down the line.

At first we thought maybe the check valve down by the well pump is failing since that is the only one in the system and it is letting water slowly drain back down into the well. So I tested this out by shutting the water off to the addition, closing the blue filter so that water in the addition wouldn't drain back, and then draining the water from the spin down filter that is on the right side of the picture. In other words, I assume I would just be draining the water from the 119gal tank and a couple feet of pipe. Pump and tank in main house shouldn't come into play since I closed the main line into the addition off. I was only able to get about 12 litres of water before it stopped flowing. I would assume with my tank set to 40PSI, no additional water coming in, and a full tank, that I would get at least a hundred and some litres of water, or at the very least way more than 12. I tried reopening the main line to the addition, waiting a bit, and retesting a couple times just in case I got the tank when it wasn't filled up or something, but got the same result or worse each time.

When I'm draining the water out, the pressure gauges at the tank and after the first filter drop to 0 very quickly, even less than 12litres is coming out some times.

Any ideas what's going on here? Is my test even valid in this situation or am I misunderstanding how the pressure tank should work on its own?

Thanks!

 

[Valveman]

You can't count on a pressure tank to store water. It will most likely be empty when the power goes off and there is nothing you can do about it. A cistern or retention tank is the only way to store water. Even when full a 119 gallon tank only holds 30 gallons of water. That is what causes the pump to cycle on and off until it destroys the diaphragm in the tank, making it hold less and less and the pump cycle even faster until it is dead as well. A Cycle Stop Valve will fix the cycling problem and a retention tank will store water.

 

[Sponsor]

 

[LLigetfa]

On a conventional pump and tank setup (no CSV), adding a second tank any distance from the first does not work well as the two tanks cannot equalize fast enough to get up to pressure before the pressure switch cuts out. In-line filters make it worse.

Then again there is what Cary said, that Murphy's Law conspires to have the power go out when the tanks are almost empty.

 

[Bannerman]

As stated, the two tanks will be refilled at different rates, which is made worse by the larger tank's distance from the smaller tank and pressure switch, and by the restricted flow into the large pressure tank through the smaller diameter PEX pipe.

While the pump is running, the smaller pressure tank will become filled first, so the pressure switch maybe rapidly sensing 60 psi and so will shut off the pump before the larger tank is filled. Water will then flow out from the smaller tank to the larger tank, which may cause the pressure switch to reactivate the pump, which maybe occuring multiple times before the larger tank is finally filled. The delay filling the larger tank, could often result the system pressure to be only marginally greater than 42 psi once the larger tank is filled.

A pressure tank's purpose is to reduce pump cycling which is why pressure tank(s) should be located only where the pressure switch is located.

Pressure switch is set to 42/60 in the main house (yes 42, can't remember why he wanted it set like that). We have synchronized the pressures in the tanks multiple times. I just readjusted the addition side so that I get 39-40PSI on the tank.

The pressure tank air precharge pressure will be typically calibrated to 2 psi lower than the pressure switch Cut-In pressure, so for a 40/60 pressure switch setting, the tank pre-charge pressure will then be 38 psi. Most pressure switches are factory calibrated for 20 psi differential pressure which should not normally be altered.

With the tank pre-charge pressure set to 2 psi lower than the pressure switch Cut-In setting, the pressure tank(s) will contain almost 0 water when the pump becomes activated, and will only contain the greatest quantity of water when the pump is shut down at 60 psi.

With the PS cutin pressure setting increased to 42 psi (18 psi differential), this then reduced the quantity of water both tanks can contain, and causes the pump to run for less time to fill the tanks, thereby increasing the amount of pump cycling.

As you mention only 3-4 feet of elevation difference between the bottom of the two pressure tanks, the pressure difference indicated on the pressure gauge within the addition should be only about 2 psi less than shown on the pressure gauge at the pressure switch within the crawl space.

 

[Reach4]

The main house has a ~30gal tank, and addition has a 119gal tank. This past year we've noticed that when the power goes out, we have little to no water reserve. We're talking flush a low flow toilet one and brush your teeth and that's it for water. The configuration is:

- Well feeds into main house where the pressure switch is located.
- Main house has a 26gal pressure tank.
- After the tank the line tees off with one pipe going to the rest of the plumbing in the main house, and the other pipe heading back outside and over to the addition . Its roughly 50 feet between the two tanks, and the new one for the addition is maybe 3 or 4 feet higher since the main house one is in a crawl space and the new one isn't.
- Line comes into the addition to another tee, with one side going to a 119gal pressure tank, and the other side heading towards the filters and the rest of the plumbing. (see picture - black pipe just to the right of the tank is the line coming from the main house)
- Pressure switch is set to 42/60 in the main house (yes 42, can't remember why he wanted it set like that). We have synchronized the pressures in the tanks multiple times. I just readjusted the addition side so that I get 39-40PSI on the tank.
- Pressure gauge right before the 119gal tank (says 40PSI), another in between two filters(top right of pic and says 42PSI), one after the last filter, and a few others down the line.

At first we thought maybe the check valve down by the well pump is failing since that is the only one in the system and it is letting water slowly drain back down into the well. So I tested this out by shutting the water off to the addition, closing the blue filter so that water in the addition wouldn't drain back, and then draining the water from the spin down filter that is on the right side of the picture. In other words, I assume I would just be draining the water from the 119gal tank and a couple feet of pipe. Pump and tank in main house shouldn't come into play since I closed the main line into the addition off. I was only able to get about 12 litres of water before it stopped flowing. I would assume with my tank set to 40PSI, no additional water coming in, and a full tank, that I would get at least a hundred and some litres of water, or at the very least way more than 12. I tried reopening the main line to the addition, waiting a bit, and retesting a couple times just in case I got the tank when it wasn't filled up or something, but got the same result or worse each time.

When I'm draining the water out, the pressure gauges at the tank and after the first filter drop to 0 very quickly, even less than 12litres is coming out some times.

Any ideas what's going on here? Is my test even valid in this situation or am I misunderstanding how the pressure tank should work on its own?

Thanks!

" So I tested this out by shutting the water off to the addition, ". The 119 gallon pressure tank is in the addition, or both pressure tanks are in the main house? I was thinking that big tank was in the addition. So if that is the case, closing the valve to the addition should have isolated the 119 gallon pressure tank from the main house.

"I was only able to get about 12 litres of water before it stopped flowing.". Were you running that 12 liters in the addition, or the main house? It must have been in the addition. How many PSI was the water pressure at the addition after you isolated the addition and before you started measuring water?

Here is a test for you:
While not using water, and pump is not running, measure the air pressure at both tank's schrader valves. Use your digital tire pressure gauge for the best resolution. What is the difference in the pressure readings?

You measure air precharge while the water pressure is zero. This test is not that-- you are measuring the air pressure while the water pressure is static in its operating range.

 

[Bannerman]

We have synchronized the pressures in the tanks multiple times. I just readjusted the addition side so that I get 39-40PSI on the tank.

To adjust the pre-charge pressure in either tank, the pump must be shut off (shut breaker off) and the plumbing system completely drained of water.

 

[siermac]

Wow, didn't expect so much back so fast haha. Thanks for all the info!

You can't count on a pressure tank to store water. It will most likely be empty when the power goes off and there is nothing you can do about it. A cistern or retention tank is the only way to store water.

The weird thing is that for the first couple years we had way more water during a power outage, it was just this year that things started diminishing. Only thing I can think of that changed was my father in-law re-did his tank and switch, but he said it was all pretty much the same, just a slightly bigger tank. In our setup, would you recommend I switch out the addition tank to a retention tank instead then?

As stated, the two tanks will be refilled at different rates, which is made worse by the larger tank's distance from the smaller tank and pressure switch, and by the restricted flow into the large pressure tank through the smaller diameter PEX pipe.

While the pump is running, the smaller pressure tank will become filled first, so the pressure switch maybe rapidly sensing 60 psi and so will shut off the pump before the larger tank is filled. Water will then flow out from the smaller tank to the larger tank, which may cause the pressure switch to reactivate the pump, which maybe occuring multiple times before the larger tank is finally filled. The delay filling the larger tank, could often result the system pressure to be only marginally greater than 42 psi once the larger tank is filled

This makes a lot of sense. Dumb question though, wouldn't the addition tank eventually get up to 60psi if no water is being used on either side?

The 119 gallon pressure tank is in the addition, or both pressure tanks are in the main house? I was thinking that big tank was in the addition. So if that is the case, closing the valve to the addition should have isolated the 119 gallon pressure tank from the main house.

"I was only able to get about 12 litres of water before it stopped flowing.". Were you running that 12 liters in the addition, or the main house? It must have been in the addition. How many PSI was the water pressure at the addition after you isolated the addition and before you started measuring water?

Big tank is in the addition, smaller tank (26 gallons) is in the main house crawl space. Was running the water in the addition. PSI on the gauges read the same after shutting off water to the addition; ~40PSI.

Here is a test for you:
While not using water, and pump is not running, measure the air pressure at both tank's schrader valves. Use your digital tire pressure gauge for the best resolution. What is the difference in the pressure readings?

I will give that a try, just need to coordinate with the in-laws haha.

To adjust the pre-charge pressure in either tank, the pump must be shut off (shut breaker off) and the plumbing system completely drained of water.

Yep, adjusting addition I shut off water there and drained, then adjusted. I should note that there is still water sitting in that spin down filter on the right in the picture, even after "draining". Only way I can get that water out is by cracking open the filter to release the air lock. Not sure if that matters?

Odd question, but when I knock on the side of the tank before and after draining the water in the addition, it sounds the same. The sound is different (more hollow) about half way up, so I think the bladder is fine, but the bottom half sound doesn't seem to change between tank being "empty" or "full". Shouldn't I expect a noticeable difference in sound when it's empty vs full?

 

[Reach4]

"Yep, adjusting addition I shut off water there and drained, then adjusted. I should note that there is still water sitting in that spin down filter on the right in the picture, even after "draining". Only way I can get that water out is by cracking open the filter to release the air lock. Not sure if that matters?"
Does not matter. What you really need is for the water pressure to be much less than the air precharge. It is usual to say that you need zero water pressure, since that is easy. But water in a filter housing is not going to mess this up.

"Odd question, but when I knock on the side of the tank before and after draining the water in the addition, it sounds the same. The sound is different (more hollow) about half way up, so I think the bladder is fine, but the bottom half sound doesn't seem to change between tank being "empty" or "full". Shouldn't I expect a noticeable difference in sound when it's empty vs full?"
Not sure. When the tank is empty of water, you still have the diaphragm tight to the tank, and that has got to deaden the sound.

With no water in it, the tank will be much lighter.

On a different related topic, you could consider putting a check valve in line with the feed to the addition. That would prevent any oscillation potential, as Bannerman talked about. You did not report the symptoms that would occur if there was oscillation. With that check valve, if the inlaws have not used water for a while, they will have a reserve if a power outage happens. The main house will not.

 

[siermac]

Thanks Reach. We did think about adding one in, so will probably do that. Any recommendation on where it should go? I assume what I have currently is a pressure reducer immediately after the water line comes out of the floor, could I just swap that out for the check valve?

I'm still getting hung up thinking about how we didn't used to have this problem. I swear we had way more water before during outages. Also randomly the pressure in the addition tank and in the gauges read 52psi last night when I went out to check on a whim. First time I've ever seen it that high. Another dumb question but should the air tank pressure, checked using the Schrader valve, increase like that?

Would running the water for a bit to kick the pump in, waiting for an hour without using any water, and then checking the water level in the addition tank be a valid test?

 

[Valveman]

Picture of this "pressure reducer" please. If in the past you have had any water during a power outage it was pure luck. Just like the last time you checked and there was only 52 PSI instead of 62 PSI, the next time power goes off there will only be 42 PSI. With a 40/60 pressure switch ALL pressure tanks in the system are empty and there is no water to use while the power is off. It is just luck of the draw if the pressure is at 42 or 62 when the power goes off. If you have a leak, the pressure will drop without any taps open. But usually the water in the tanks has just been used a little at a time leaving the tank almost empty when the power goes off.

If you want a dependable supply of water when the power is off a cistern or retention tank is needed.

 

[siermac]

Picture of this "pressure reducer" please.

Sure thing, here you go.

Just to confirm, if we get a reserve tank then we would still need power to the pump after that tank during an outage in order to get water throughout the house, correct?

Also if we were to replace the pressure tank in the addition with a retention tank, would we still have the issue where the pressure tank in the main house fills to 60psi, then drains over to the addition to fill the reserve tank, and then kicks the pump back on to fill the pressure tank again and so on? And what if in that scenario we take the 119gal pressure tank that's currently in the addition and move it to the main house instead to replace the 26gal one?

I suppose what I'm wondering there is how does it work haha. Does the reserve tank just always stay full?

 

[Bannerman]

wouldn't the addition tank eventually get up to 60psi if no water is being used on either side?

Not likely. When the pressure switch senses 60 psi at the smaller tank, the PS will shut off the pump.

If the larger distant tank is not filled at that time, then water will exit from the smaller tank, flowing to the larger tank until the pressure is equalized between both tanks. Because water exited from the smaller tank, the smaller tank's pressure will then be less than 60. If the pressure didn't drop fully to 42 to cause the pressure switch to reactivate the pump, then the equalized pressure between both tanks will be somewhere between 43 and 59 psi, but probably, usually closer to 43 than 59.

 

[Valveman]

Sure thing, here you go.
View attachment 96297
View attachment 96298

Just to confirm, if we get a reserve tank then we would still need power to the pump after that tank during an outage in order to get water throughout the house, correct?

Also if we were to replace the pressure tank in the addition with a retention tank, would we still have the issue where the pressure tank in the main house fills to 60psi, then drains over to the addition to fill the reserve tank, and then kicks the pump back on to fill the pressure tank again and so on? And what if in that scenario we take the 119gal pressure tank that's currently in the addition and move it to the main house instead to replace the 26gal one?

I suppose what I'm wondering there is how does it work haha. Does the reserve tank just always stay full?

That black pipe coming up is attached to a check valve then a ball valve, no pressure reducer. There should be no check valve or ball valve at that location, but it is not causing less water to come from the tanks. If you get less water out of the tanks than before as the pressure drops form 63 to 43, then most likely one or both tanks are bad. Check the tank air pressure, measure the water that comes out, and you will know.

 

[siermac]

That black pipe coming up is attached to a check valve then a ball valve, no pressure reducer

Wow, yep you're right. I didn't see the arrow on it before because of the colouring so didn't think it was a check valve. Went back and looked again with some better lighting and can see it now. Well that's good to know, so no need to do that install now haha.

Air tank pressure seems fine in both tanks, around 40PSI at empty.

If the larger distant tank is not filled at that time, then water will exit from the smaller tank, flowing to the larger tank until the pressure is equalized between both tanks. Because water exited from the smaller tank, the smaller tank's pressure will then be less than 60. If the pressure didn't drop fully to 42 to cause the pressure switch to reactivate the pump, then the equalized pressure between both tanks will be somewhere between 43 and 59 psi, but probably, usually closer to 43 than 59.

That makes sense. Would we have the same issue if we replace the larger tank with a reserve tank instead of a pressure tank then?