Max PSI for 1.5HP Submersible?

[Theplayer11]

Greenhouse use. 1.5HP 15GPM Berkeley submersible pump 200' down installed last year. No control box or Amtrol tank, just turn on/off through breaker switch and water goes directly to garden hose.(I know, not optimal set up...lol) Currently has a 100 PSI relief valve installed on manifold at top off well casing.
We water our plants by standard hose, lengths run 250-300'. When watering with 1 hose only, the pressure will build up over 100PSI, so we usually run a second line into a holding tank and keep PSI around 90. Watering the plants with 1 hose at 90 PSI ,the pressure out of the 250-300' hose is really good for our needs, but we would like to know if we could go higher on the PSI and not have to run a second line to lower pressure below 100 PSI.
First question, I assume running at 90 PSI is ok? Secondly, how high on the PSI can we actually go to not do damage to the pump? If we can run higher PSI, I would set relief valve higher, or get a new one.
Last question, when a relief valve is triggered, can it still be used? I ask because the valve was working last year, but I recently had PSI go over 100 and the valve did not open.
Any input appreciated, thanks.

Pump manual states this:
Shut off head: feet-403, PSI 174. Is this relevant to my questions?

 

[Reach4]

First question, I assume running at 90 PSI is ok? Secondly, how high on the PSI can we actually go to not do damage to the pump? If we can run higher PSI, I would set relief valve higher, or get a new one.

Yes. You want the pump to be pumping water, but otherwise should not hurt the pump. If anything to worry about, it would be the pipe.

Last question, when a relief valve is triggered, can it still be used? I ask because the valve was working last year, but I recently had PSI go over 100 and the valve did not open.

They reset. The calibration is not that tight.

Another way to regulate the pressure for your irrigation is to use a CSV to add a variable backpressure to limit the PSI out, even tho the GPM use changes. I would still want to have something over maybe 5 psi flowing when the pump is pumping. Don't deadhead the pump.

pump manual states this:
Shut off head: feet-403, PSI 174. Is this relevant to my questions?

Somewhat. It shows that you are unlikely to burst the pipe, even if it is 160 psi rated poly pipe.

 

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[Theplayer11]

Thanks for the reply. Someone told me that I must be in the pump curve specs or I would damage the pump and I should have a well tank and control box installed. A tank is not an option for us at this point and not needed for our needs, I believe.(obviously we have to be careful to turn on/off every time we start and finish and not dead head)
The pump curve chart(link below) shows 0 to 80 PSI, does that mean running higher than 80 will damage the pump in any way?
The pressure gauge is installed on the manifold on top of the well casing where shut off valves for the hoses are attached. So tweaking the shut off valves controls the PSI.

15GPM, 1.5HP
https://www.pentair.com/content/dam...eley/spec-sheets/jp-series-specifications.pdf

 

[Reach4]

The pump curve chart(link below) shows 0 to 80 PSI, does that mean running higher than 80 will damage the pump in any way?

No, unless their is not enough cooling at the motor. If the pump had a flow inducer sleeve over the motor, that would maximize cooling, even with a top-feeding well.

You could be more power-efficient with a lower-HP pump. The pump does more GPM per kWh in the dark part of the curve.

 

[Valveman]

It depends on how deep the water is in your 200' deep well. That pump can still make 100 PSI even if the water level is at 170'. But if the water level is at 10', that pump will make 170 PSI at the surface. Not even 170 PSI will hurt the pump, as long as it is still pumping at least 1 GPM. So, you can have as much pressure as you want.

However, controlling with a pressure relief valve is not good. They are made for emergencies only and will quit working if used too many times. They will either fail to open or fail to close.

Using a CSV1A on the pump set for 100 PSI and installing the pressure relief valve after the CSV1A, the pressure relief would only be needed if you left the pump on and was using less than 1 GPM. This would give you 100 PSI constant on the hose and make your pressure relief valve be used for protection only.

Adding a 10 gallon pressure tank and a 90/110 pressure switch, as in a PK1A kit, would give the same strong constant pressure and be completely automatic. This way you just turn a faucet on when you want 100 PSI on a hole and the system will come on when needed and go off when not. No more need to make sure and turn the pump off when you are finished watering, just turn off the faucet to the hose.