keep pump running at high pressure with pressure switch

[RTL]

Hello,
I'm pumping water from a lake with a 2hp/70 psi pump that has a 90 feet of head to a small sprinkler system. So I'm losing a lot of PSI by the time it hits the heads, but enough psi to run the sprinkler system when the pump is running. The pressure switch is set to shutoff at the pumps maximum psi but when it does the pressure tank doesn't supply enough water as the pressure decreases to the cut in pressure for the pump. The pump needs a pressure switch as it is also used for water taps @ 70 foot of elevation and also at pump level. What are my options? I basically want the pump to run at max while the sprinkler valves are open and yes I have a pressure release valve. Can I run a pump relay and a pressure switch and has anyone done that and how would you wire that solution. Other than running the water taps through the sprinkler system can the pump relay somehow turn on the pump for the water taps? Jeez...

 

[Reach4]

Are you saying that the pressure rises high enough to shut off the 40/60 psi pressure switch, even if the sprinkler system is running? 90 feet of head is only 39 PSI, so I would not expect the pump to shut off while the sprinker is running.

Now if the pump delivers more pressure while the pump is running, maybe adjusting the pressure switch higher would work for you.

So yes, you could switch a relay to convert between using the pressure switch and being always on. But I don't think you would need that.

 

[Sponsor]

 

[Valveman]

You don't need a relay if you have a pressure switch. Sounds like you just need a check valve to hold the pressure tank water from going back through the pump after it shuts off.

 

[RTL]

Are you saying that the pressure rises high enough to shut off the 40/60 psi pressure switch, even if the sprinkler system is running? 90 feet of head is only 39 PSI, so I would not expect the pump to shut off while the sprinker is running.

Now if the pump delivers more pressure while the pump is running, maybe adjusting the pressure switch higher would work for you.

So yes, you could switch a relay to convert between using the pressure switch and being always on. But I don't think you would need that.

Yes the pump shuts off while the sprinklers are running and when it does the pressure drops too low to run the sprinklers until the pump kicks back on. Can't adjust the pressure switch any higher as it is currently at max. I need a way to keep the pump running while the sprinkler system is running.

 

[RTL]

You don't need a relay if you have a pressure switch. Sounds like you just need a check valve to hold the pressure tank water from going back through the pump after it shuts off.

View attachment 93841View attachment 93841

These links don't work. I have a check valve installed directly after the pump.

 

[Valveman]

I need a way to keep the pump running while the sprinkler system is running.

That is exactly what a Cycle Stop Valve does. The check valve should keep the pressure in the tank until you open a tap, which keeps the pump from cycling when not using water. The CSV is what keeps the pump from cycling WHILE you are using water.

 

[Bannerman]

Can't adjust the pressure switch any higher as it is currently at max.

While R4 mentioned 40/60 psi, you only said 'Max', but you haven't stated the actual pressure switch settings, nor have you defined the pressure tank pre-charge pressure.

 

[RTL]

Are you saying that the pressure rises high enough to shut off the 40/60 psi pressure switch, even if the sprinkler system is running? 90 feet of head is only 39 PSI, so I would not expect the pump to shut off while the sprinker is running.

Now if the pump delivers more pressure while the pump is running, maybe adjusting the pressure switch higher would work for you.

So yes, you could switch a relay to convert between using the pressure switch and being always on. But I don't think you would need that.

You don't need a relay if you have a pressure switch. Sounds like you just need a check valve to hold the pressure tank water from going back through the pump after it shuts off.

View attachment 93844

I have a check valve. The pump shuts off just fine, but the problem is that I don't want it to shut off while using the sprinkler system. The pressure switch is set to the maximum psi the pump will produce

 

[RTL]

While R4 mentioned 40/60 psi, you only said 'Max', but you haven't stated the actual pressure switch settings, nor have you defined the pressure tank pre-charge pressure.

the pressure switch is set to cut out at the maximum pressure the pump will produce which I believe is around 52 PSI. Any higher and the pump will not shut off when not in use.

 

[Reach4]

the pressure switch is set to cut out at the maximum pressure the pump will produce which I believe is around 52 PSI. Any higher and the pump will not shut off when not in use.

So if we assume the pressure switch cut-off is 52 psi, and the pump can only produce 53 psi when there is no water being used, then logically the water pressure should never get as high as 52 psi while the irrigation sprinklers are on.

So what is the deal? Is the pressure gauge looking at the same pressure that the pressure switch is? Consider posting a photo that includes the pressure switch, pressure gauge, and the input to the pressure tank.

ADDED: "Yes the pump shuts off while the sprinklers are running and when it does the pressure drops too low to run the sprinklers until the pump kicks back on. "
How long does the pump stay off? If 3 seconds, that points one way, and if 30 seconds, that points a different way.

If you watch the pressure gauge during an unwanted shut-off episode, what does the pressure gauge do?

The reason I was suggesting a photo, there should not be much pipe between the tee to the pressure switch and the input to the pressure tank.

 

[Valveman]

I have a check valve. The pump shuts off just fine, but the problem is that I don't want it to shut off while using the sprinkler system. The pressure switch is set to the maximum psi the pump will produce

Adding a Cycle Stop Valve will keep the pump from cycling on and off while water is being used. However, your pump only builds 52 PSI. Those irrigation pumps don't really build enough pressure to work with a pressure switch or a Cycle Stop Valve. Jet pumps make much more pressure and work better with a pressure switch and a Cycle Stop Valve. You really shouldn't set a pressure switch off setting anywhere close to the max pressure the pump can build. At 52 PSI that pump is not moving any water and will get hot. But because it only builds 52 PSI, you should be able to set the pressure switch shut off point at like 50-51 PSI, where it will not cycle off when using a fairly small sprinkler zone. It is just a tricky setting and hard to maintain it that close.

 

[Fitter30]

What turns the sprink system on and is it by the pump?

 

[RTL]

What turns the sprink system on and is it by the pump?

We have 5 zones on a timer. The valve box and timer is 25 feet higher than the pump

 

[RTL]

Adding a Cycle Stop Valve will keep the pump from cycling on and off while water is being used. However, your pump only builds 52 PSI. Those irrigation pumps don't really build enough pressure to work with a pressure switch or a Cycle Stop Valve. Jet pumps make much more pressure and work better with a pressure switch and a Cycle Stop Valve. You really shouldn't set a pressure switch off setting anywhere close to the max pressure the pump can build. At 52 PSI that pump is not moving any water and will get hot. But because it only builds 52 PSI, you should be able to set the pressure switch shut off point at like 50-51 PSI, where it will not cycle off when using a fairly small sprinkler zone. It is just a tricky setting and hard to maintain it that close.

Yep exactly the way it is set up, but cycles off during irrigation which reduces pressure too low to run sprinklers effectively, so I need the pump to stay running while sprinkler are on

 

[RTL]

So if we assume the pressure switch cut-off is 52 psi, and the pump can only produce 53 psi when there is no water being used, then logically the water pressure should never get as high as 52 psi while the irrigation sprinklers are on.

So what is the deal? Is the pressure gauge looking at the same pressure that the pressure switch is? Consider posting a photo that includes the pressure switch, pressure gauge, and the input to the pressure tank.

ADDED: "Yes the pump shuts off while the sprinklers are running and when it does the pressure drops too low to run the sprinklers until the pump kicks back on. "
How long does the pump stay off? If 3 seconds, that points one way, and if 30 seconds, that points a different way.

If you watch the pressure gauge during an unwanted shut-off episode, what does the pressure gauge do?

The reason I was suggesting a photo, there should not be much pipe between the tee to the pressure switch and the input to the pressure tank.

I'm wondering if the 90 feet of elevation from pump to highest head is the problem when the pressure switch is by the pump.

 

[RTL]

So if we assume the pressure switch cut-off is 52 psi, and the pump can only produce 53 psi when there is no water being used, then logically the water pressure should never get as high as 52 psi while the irrigation sprinklers are on.

So what is the deal? Is the pressure gauge looking at the same pressure that the pressure switch is? Consider posting a photo that includes the pressure switch, pressure gauge, and the input to the pressure tank.

ADDED: "Yes the pump shuts off while the sprinklers are running and when it does the pressure drops too low to run the sprinklers until the pump kicks back on. "
How long does the pump stay off? If 3 seconds, that points one way, and if 30 seconds, that points a different way.

If you watch the pressure gauge during an unwanted shut-off episode, what does the pressure gauge do?

The reason I was suggesting a photo, there should not be much pipe between the tee to the pressure switch and the input to the pressure tank.

I'll do this testing

 

[Bannerman]

wondering if the 90 feet of elevation from pump to highest head is the problem

90 feet of vertical rise, is the same as ~38 psi pressure reduction. As the pump can barely produce only 53 psi, the maximum pressure at the sprinkler head 90' above the pump will be only 15 psi. Since most pressure switches are calibrated for 20 psi differential between cut out and cut in, the pressure at the sprinkler head at the highest elevation will be a negative pressure until some time after the pump is activated and building pressure.
.

 

[Valveman]

We have 5 zones on a timer. The valve box and timer is 25 feet higher than the pump

Can you just connect the pump to the pump start relay in the irrigation timer? 90' is the same as 40 PSI, so it will have to start higher than 40 PSI, which is hard to do with a pump than only makes 52 PSI. With 40 PSI loss up the hill I don't see how the sprinklers are working. Usually the 40 PSI elevation is added to what the sprinklers need.

 

[Bannerman]

Usually the 40 PSI elevation is added to what the sprinklers need.

This implies choosing a pump with a greater head capacity.

 

[Valveman]

This implies choosing a pump with a greater head capacity.

Yes. If you want 40 PSI at the sprinklers and you lose 38 PSI on the hill getting up there, you need a pump that can supply the water you need at 78 PSI.