2 Pump System Design, will this work OK?

[RockfordPI]

Will the pump system in the attached pic work (scroll down to see all)? I am specifically worried about the pumps pumping against each other and the check valve configurations/locations.

Background. Originally had only the 240' well, submersible pump, and large bladder tank. Initially (20 years ago) well was producing 4-5 gallons/minute. Recently installed Sod and tried to water. Discovered well is now only producing 1/2 - 1/3 gallon/minute (which apparently was sufficient to supply household given the larger bladder tank and pumptec protector)

6 weeks lead time here to get a well drilled (I wish I knew how to drill wells as one local driller is 87, the other is 74, looks like a great business opportunity).

So, I installed a 3000 gallon water tank outside. Submersible pump now fills tank from well. Franklin Pumptec shuts off sub pump on run dry, delays for 90 minutes and restarts, otherwise Sub pump shuts off on tank full.

I added a centrifugal pump to provide water/pressure to the house and sprinklers.

I also left the sub pump connected to the house so I could, if needed, close the valve to the 3000 gallon tank and revert to pumping water directly from well into house (with pressure switch setup accordingly).

The four states are
1 No Pumps Running (I am guessing I am OK there)
2. Submersible only running
3. Centrifugal only running
4. BOTH pumps running (this one has me concerned)

Systems seems to work OK, but I am paranoid about the sound of the centrifugal pump sometimes. Any feedback is appreciated.

 

[Fitter30]

Centrifugal pumps usually need suction head to work properly. Brand model, hp of pump.

 

[Sponsor]

 

[Reach4]

I think that works.

Don't close the valve unless the pumps are both off.

 

[Valveman]

Try it like this drawing. You really don't want to run the submersible unless the booster quits and you need water in the house over a holiday or something.

 

[RockfordPI]

Centrifugal pumps usually need suction head to work properly. Brand model, hp of pump.

I understand the general concept of head, but not "suction head". Can you help me understand that please.

The centrifugal pump is a one HP Drummond sprinkler pump from harbor freight:
https://www.harborfreight.com/1-HP-Portable-Sprinkler-Pump-1075-GPH-63320.html

 

[RockfordPI]

Try it like this drawing. You really don't want to run the submersible unless the booster quits and you need water in the house over a holiday or something.

View attachment 63619

I think what I have is very similar to your diagram, though I use the same inlet (with check valve) to both fill and draw from the storage tank (that was one of my concerns).

I also don't have the pside kick, but my pump is only starting 16 times daily. Given that my well is producing 1/2 gallon or less per minute, would the pside kick really save me that many starts? I have a 1 gpm dole valve that I debated putting on the submersible output but did not see where that alone would save me any pump cycles.

Not sure I understand what you mean by not running the submersible unless the booster quits. I have to run the sub to keep the storage tank full.

PS: Not disagreeing with you or discounting your advice (which I greatly appreciate) I am, just trying to be sure I understand

 

[Valveman]

Your check valve on the well pump is not in the right place. Drawing and replenishing water to the storage tank from the same bottom outlet is not good. Where the check valve is now, the storage tank will drain back into the well when the pump shuts off. Even if the check is placed in the right spot this can happen if the check valve fails. Better to replenish the storage tank from the top with an air gap to prevent back flow.

The well pump shouldn't be teed into the sprinkler line. It doesn't have a pressure switch and tank.

The pressure switch for the centrifugal is too far from the pressure tank.

Those Drummond pumps are cheap and will barely build 50 PSI. It probably doesn't pump enough for sprinklers or just barely. Otherwise you would need a CSV to keep the booster from being too large and cycling on/off continuously, which could be hundreds of times per day. Size the pump to match the sprinklers exactly, and you won't need a CSV. However, the CSV keeps you from having to size sprinklers and pump exactly and would allow the use of a much smaller pressure tank either way.

 

[RockfordPI]

Your check valve on the well pump is not in the right place. Drawing and replenishing water to the storage tank from the same bottom outlet is not good. Where the check valve is now, the storage tank will drain back into the well when the pump shuts off. Even if the check is placed in the right spot this can happen if the check valve fails. Better to replenish the storage tank from the top with an air gap to prevent back flow.

The well pump shouldn't be teed into the sprinkler line. It doesn't have a pressure switch and tank.

The pressure switch for the centrifugal is too far from the pressure tank.

Those Drummond pumps are cheap and will barely build 50 PSI. It probably doesn't pump enough for sprinklers or just barely. Otherwise you would need a CSV to keep the booster from being too large and cycling on/off continuously, which could be hundreds of times per day. Size the pump to match the sprinklers exactly, and you won't need a CSV. However, the CSV keeps you from having to size sprinklers and pump exactly and would allow the use of a much smaller pressure tank either way.

Thanks for the info. Actually I already have a pressure switch next to the bladder tank from previous setup, all I need to do is change my wiring to fix that issue.

There is also another check valve at the bottom of the well, but your point is well taken. I will definitely move the fill line to the top of the water storage tank.

As for the well pump Tee'd into sprinkler line without a switch/tank, that is only there for temp backup in case the other pump fails. Normally that line can never really build pressure since it is pumping open end into the storage tank. If other pump fails, storage tank valve will be closed in which case I understand I would have to re-connect the pressure switch to sub pump

Do I need to add another valve to keep the sub pump from pumping through the centrifugal pump in the case where the latter fails?

The drummond pump actually builds 70 PSI, but I understand it is not the best. Will likely upgrade to a better pump when / if I get the kinks resolved.


Thanks again for all of your help.

 

[Reach4]

Where the check valve is now, the storage tank will drain back into the well when the pump shuts off.

I figure the well has a check valve at the bottom, so water cannot drain back into the well.

 

[Valveman]

I figure the well has a check valve at the bottom, so water cannot drain back into the well.

Unless there is a hole in the pipe or the bottom check fails. Still safer to fill from the top with an air gap.

 

[RockfordPI]

I figure the well has a check valve at the bottom, so water cannot drain back into the well.

Yes, there is a CV at bottom of well so I am OK in the very short term. However, VM makes a good point, it could fail and potentially drain 3000 gallons back into the well.

I always intended to fill from top, just have not had a chance to climb to the top and add another hole in the tank.

I am just flying by the seat of my pants here trying to keep water to the house and save 9000 sq ft of sod and I appreciate everybody double checking my work and providing input.

 

[Valveman]

Do I need to add another valve to keep the sub pump from pumping through the centrifugal pump in the case where the latter fails?

The check valve on the suction side should be enough.