Pressure Tank & Pump Setup with Elevated Cistern - Need Advice!

[Jcwright30]

First my setup (see pics):

• I have a spring fed cistern (600+ gallons). Call this at 600' above sea level.
• This cistern runs down to a bank barn. Call this at 500' above sea level.
• From the barn it feeds into the house. Call this 510' above sea level.
• I have a yard hydrant at the barn which produces massive flow and volume.
• In the house i have a shallow well pump (FP4012-10 flotec) and a pressure tank (FP7120-08).
• Pump is mounted on top of the tank with a pressure switch. There is a pressure gauge at the tee of the tank along with a hose connection for drain-off, etc.
• There is a check valve (questionably not working correctly - I'll get to this later) on the suction side right where the water line enters the house. This check valve is mounted vertically (acceptable) but is about 15 linear feet away from the inlet of the pump.
• All plumbing is 3/4" until i come off of the water heater and tee off to various fixtures.

The problem:

• Because the cistern is elevated I am receiving a constant pressure in the house of about 28 psi. I have had this pump turned off due to issues - so naturally pressurized works but it's not great. Water pressure throughout the house is lackluster and if you flush a toilet while a shower is running it's almost a trickle. This is my key motivation to get things working again.
• Going back to the head pressure I have - I believe that the check valve isn't doing its job (no fault of the check value itself as it's likely working per spec) but if I turn the pump on and let it pressure up and then immediately close the shutoff valve on the inlet side pressure in the tank holds constant. If i leave that inlet valve open as it should be the water pressure immediately falls down to ~28psi.
• I believe what might be happening is the Cracking pressure on the check valve is likely very low (something likely less than 2 PSI). So when the pump shuts off the check valve never closes and water is back fed until natural head pressure is met (or cut-in of pump)

The ask:

• I'd love any suggestions or ideas to get this setup working. I think what is particularly unique in this situation is the head pressure.

Thanks in advance!

 

[Reach4]

• I believe what might be happening is the Cracking pressure on the check valve is likely very low (something likely less than 2 PSI). So when the pump shuts off the check valve never closes and water is back fed until natural head pressure is met (or cut-in of pump)

The spring-loaded check valve is bad.

Is there bigger pipe down to the barn? If you could run new 1-1/4 polyethylene pipe to, or near to, the WH tee, you could probably get along nicely with no booster. Maybe throttle the toilet fill valves.

 

[Sponsor]

 

[LLigetfa]

Agreed, bad check valve. The positive head has no bearing on the operation. The check valve only sees the pressure differential across it, not pressure related to atmosphere.

 

[Jcwright30]

Looking to explore all possible options to rectifiy this situation so @Reach4 and @LLigetfa I will ask a few things.

1) @Reach4 it looks like the line that comes into the house from the barn is 3/4" also (it might be 1" poly which is then reduced to 3/4" at the shutoff. If that was 1" I could re-run 1" directly to the WH tee. I assume you are thinking I'd gain some pressure back by the larger line some close to 90*.433 = 39 PSI)?
2) @Reach4 & @LLigetfa - you both think the check valve is bad which is also my suspision - I'm thinking if I change that out I'll move it directly to the inlet of the pump. vs replacing it where it is today or do you think that 15' of linear piping from inlet to check valve doesn't matter?

 

[Reach4]

it looks like the line that comes into the house from the barn is 3/4" also (it might be 1" poly which is then reduced to 3/4" at the shutoff. If that was 1" I could re-run 1" directly to the WH tee. I assume you are thinking I'd gain some pressure back by the larger line some close to 90*.433 = 39 PSI)?

That should make good improvement. To know the static pressure, just throw a garden hose thread pressure gauge onto the something when no water is being used. Maybe have a new bigger path that bypasses the pump.

A laundry tap, hose spigot, or the drain on the water heater are good places to hook to temporarily.

Another interesting test would be to put a pressure gauge on the yard hydrant, and then run the shower or tub. See how much drop there is with 2.5 or 5 gpm being used.

Expect a spring-loaded check valve to drop about 1 or 2 psi to overcome the spring, and then there is further pressure drop due to flow. I think I would put the check valve on the output of the pump and before the pressure switch and pressure tank. You could take a movie of the gauge while you open and close valves in the house.

https://terrylove.com/forums/index.php?threads/recommended-check-valve-for-rainwater-cistern.63207/

1 inch SIDR polythene pipe is bigger than 1 inch pex or 1 inch CVPV. You could come up with 1-1/4 from the poly, and not have that be a waste. What is the connection at the poly -- barbed adapter or what?

 

[Valveman]

A check valve mounted vertically in the down position isn't best, but should still work. Mount a new metal, spring loaded, poppet style check valve to the horizontal pipe before the pump. BTW, repeated slamming from the pump cycling on and off is the most common cause of check valve failure.

 

[Reach4]

Mount a new metal, spring loaded, poppet style check valve to the horizontal pipe before the pump.

What is the advantage of before the pump vs after?

 

[Valveman]

What is the advantage of before the pump vs after?

Well in this case the pressure switch is mounted to the pump and the check valve has to be before that. Even when the switch is on the tank it is best to start a pump under pressure. Plus, it helps eliminate water hammer because a pump starting at zero pressure can punch a check valve on the discharge side.

 

[Reach4]

The pressure switch on the pump explains it.

 

[Jcwright30]

That should make good improvement. To know the static pressure, just throw a garden hose thread pressure gauge onto the something when no water is being used. Maybe have a new bigger path that bypasses the pump.

A laundry tap, hose spigot, or the drain on the water heater are good places to hook to temporarily.

Another interesting test would be to put a pressure gauge on the yard hydrant, and then run the shower or tub. See how much drop there is with 2.5 or 5 gpm being used.

Expect a spring-loaded check valve to drop about 1 or 2 psi to overcome the spring, and then there is further pressure drop due to flow. I think I would put the check valve on the output of the pump and before the pressure switch and pressure tank. You could take a movie of the gauge while you open and close valves in the house.

https://terrylove.com/forums/index.php?threads/recommended-check-valve-for-rainwater-cistern.63207/

1 inch SIDR polythene pipe is bigger than 1 inch pex or 1 inch CVPV. You could come up with 1-1/4 from the poly, and not have that be a waste. What is the connection at the poly -- barbed adapter or what?

Thanks! I took pics but cannot tell if this is 1" or 3/4" poly. Here's a closeup. This little stub of poly is the only thing that i have exposure to. On the second picture I posted at the top of the pic that shows that 3/4" copper that connects to the shut-off valve (for a size comparison from the 3/4 copper to the poly).
View attachment 72354

 

[Jcwright30]

That should make good improvement. To know the static pressure, just throw a garden hose thread pressure gauge onto the something when no water is being used. Maybe have a new bigger path that bypasses the pump.

A laundry tap, hose spigot, or the drain on the water heater are good places to hook to temporarily.

Another interesting test would be to put a pressure gauge on the yard hydrant, and then run the shower or tub. See how much drop there is with 2.5 or 5 gpm being used.

Expect a spring-loaded check valve to drop about 1 or 2 psi to overcome the spring, and then there is further pressure drop due to flow. I think I would put the check valve on the output of the pump and before the pressure switch and pressure tank. You could take a movie of the gauge while you open and close valves in the house.

https://terrylove.com/forums/index.php?threads/recommended-check-valve-for-rainwater-cistern.63207/

1 inch SIDR polythene pipe is bigger than 1 inch pex or 1 inch CVPV. You could come up with 1-1/4 from the poly, and not have that be a waste. What is the connection at the poly -- barbed adapter or what?

Thanks! I took pics but cannot tell if this is 1" or 3/4" poly. Here's a closeup. This little stub of poly is the only thing that i have exposure to. On the second picture I posted at the top of the pic that shows that 3/4" copper that connects to the shut-off valve (for a size comparison from the 3/4 copper to the poly).
View attachment 72354 View attachment 72355

 

[Jcwright30]

That should make good improvement. To know the static pressure, just throw a garden hose thread pressure gauge onto the something when no water is being used. Maybe have a new bigger path that bypasses the pump.

A laundry tap, hose spigot, or the drain on the water heater are good places to hook to temporarily.

Another interesting test would be to put a pressure gauge on the yard hydrant, and then run the shower or tub. See how much drop there is with 2.5 or 5 gpm being used.

Expect a spring-loaded check valve to drop about 1 or 2 psi to overcome the spring, and then there is further pressure drop due to flow. I think I would put the check valve on the output of the pump and before the pressure switch and pressure tank. You could take a movie of the gauge while you open and close valves in the house.

https://terrylove.com/forums/index.php?threads/recommended-check-valve-for-rainwater-cistern.63207/

1 inch SIDR polythene pipe is bigger than 1 inch pex or 1 inch CVPV. You could come up with 1-1/4 from the poly, and not have that be a waste. What is the connection at the poly -- barbed adapter or what?

Thanks! I took pics but cannot tell if this is 1" or 3/4" poly. Here's a closeup. This little stub of poly is the only thing that i have exposure to. On the second picture I posted at the top of the pic that shows that 3/4" copper that connects to the shut-off valve (for a size comparison from the 3/4 copper to the poly).
View attachment 72354 View attachment 72355

 

[Jcwright30]

That should make good improvement. To know the static pressure, just throw a garden hose thread pressure gauge onto the something when no water is being used. Maybe have a new bigger path that bypasses the pump.

A laundry tap, hose spigot, or the drain on the water heater are good places to hook to temporarily.

Another interesting test would be to put a pressure gauge on the yard hydrant, and then run the shower or tub. See how much drop there is with 2.5 or 5 gpm being used.

Expect a spring-loaded check valve to drop about 1 or 2 psi to overcome the spring, and then there is further pressure drop due to flow. I think I would put the check valve on the output of the pump and before the pressure switch and pressure tank. You could take a movie of the gauge while you open and close valves in the house.

https://terrylove.com/forums/index.php?threads/recommended-check-valve-for-rainwater-cistern.63207/

1 inch SIDR polythene pipe is bigger than 1 inch pex or 1 inch CVPV. You could come up with 1-1/4 from the poly, and not have that be a waste. What is the connection at the poly -- barbed adapter or what?

Thanks! I took pics but cannot tell if this is 1" or 3/4" poly. Here's a closeup. This little stub of poly is the only thing that i have exposure to. On the first picture I posted here, at the top of the pic that shows that 3/4" copper that connects to the shut-off valve (for a size comparison from the 3/4 copper to the poly).
View attachment 72354 View attachment 72355

 

[Jcwright30]

A check valve mounted vertically in the down position isn't best, but should still work. Mount a new metal, spring loaded, poppet style check valve to the horizontal pipe before the pump. BTW, repeated slamming from the pump cycling on and off is the most common cause of check valve failure.

Based on my setup (assuming i can't expand my 3/4" line inside house to WH tee to 1" or 1 1/4") and I need to replace and relocate the location of the check value to right before the inlet of the pump I am curious if you think there are certain specs I should follow. Most particular, the cracking pressure. Is something in the range of 2 PSI ok or should I look for something else? Maybe it doesn't matter.

 

[Valveman]

A higher cracking pressure will stay closed better. It won't make much difference once the pump starts. Not that critical. And there should already be one on the pump. It may start working once you remove the extra above ground check as the bottom check will have more pressure keeping it closed.

 

[Reach4]

Based on my setup (assuming i can't expand my 3/4" line inside house to WH tee to 1" or 1 1/4") and I need to replace and relocate the location of the check value to right before the inlet of the pump I am curious if you think there are certain specs I should follow. Most particular, the cracking pressure. Is something in the range of 2 PSI ok or should I look for something else? Maybe it doesn't matter.

I would be careful with that connection, holding the barb as you unscrew that reducer. I would tee off, and add a path to bypass the pumping system for times when gravity is enough or if you are working on the pump system. I think the bypass could bypass the check valve, and thus not have the pressure drop of a check valve.

When you have a tee, there is the less resistance straight though compared to going through the side port.

The check valve could go on the output of the pump if you either switched to using a new pressure switch at the pressure tank, or routed the sense tube to the pressure tank instead of being routed to the pump housing.

If that is 3/4 inch poly coming in, you can still increase to 1 inch for some new stuff. If you increased to 1 inch and then piped with 1 inch pex or copper for new stuff, that could be a reasonable move.

 

[Jcwright30]

A higher cracking pressure will stay closed better. It won't make much difference once the pump starts. Not that critical. And there should already be one on the pump. It may start working once you remove the extra above ground check as the bottom check will have more pressure keeping it closed.

Thanks! I want to make sure I follow - I don't believe there is a check in the FP4012-10 pump. Based on my above ground cistern setup the only check valve I am aware of is the one that is immediately inline when the water line enters the house. My thought was to remove that and add the new check valve directly at the inlet of the pump.

 

[wwhitney]

Because the cistern is elevated I am receiving a constant pressure in the house of about 28 psi.

If 28 psi is your static pressure (no flow) with no pump and no pressure tank, that means the water level in the cistern is 65' higher than where you are taking the measurement.

I assume you are thinking I'd gain some pressure back by the larger line some close to 90*.433 = 39 PSI)?

Your elevations must be off, as it's 65', not 90'. And a larger line won't change the static pressure; what it will do is reduce the frictional pressure loss that occurs during flow. Which is causing the the symptom "if you flush a toilet while a shower is running it's almost a trickle."

But, increasing the pipe size in the house won't do anything about the frictional pressure loss between the cistern and the house. Which is why Reach4 suggested taking 2 measurements at the yard hydrant--static pressure, and pressure while the shower is running. The difference tells you the frictional pressure loss between cistern and yard hydrant (and will increase with increasing flow, so with a helper or a video camera you could also take a pressure measurement at the yard hydrant when the toilet is flushed during a shower). Add to that the frictional pressure loss between yard hydrant and house, and that's all the pressure available to you at the house, without upsizing the outdoor piping.

Cheers, Wayne

 

[Valveman]

Thanks! I want to make sure I follow - I don't believe there is a check in the FP4012-10 pump. Based on my above ground cistern setup the only check valve I am aware of is the one that is immediately inline when the water line enters the house. My thought was to remove that and add the new check valve directly at the inlet of the pump.

You are correct. I was thinking submersible pump. But with 28 PSI coming in cracking pressure or where you put the check valve won't make much difference.

 

[Reach4]

But with 28 PSI coming in cracking pressure or where you put the check valve won't make much difference.

Unless there was a possibility of cavitation. May not be possible at the flow rates anticipated.