Sizing a Pump

Provided your nozzle is a general purpose smooth bore 0.5 inch ID nozzle, it's discharge Q will be some 30 gpm at 15 psi nozzle pressure. I assume you speak of water at around 60 - 65 deg F. As your supply hose is only 6 ft long, it's friction losses will be negligible and not worth bothering about. So have a pump to supply around 35 gpm to a 35-36 foot head. You can run your pump on either 115 or 230 VAC... it is up to you.

oznative - Beware of the US - Imperial GMP conversion possibly needed in post 1.

I think you will find that most fractional pumps will deliver the 15 psi. A 1/2 hp can run on 115v and 11.5 amp and will deliver about 10 gpm on open discharge and slightly less at 15 psi. If you want higher outputs you may have to go to a higher hp and will likely need 230v. Based on your breaker of 20 amps I would not exceed 1/2 hp. The starting amps of this 1/2 hp will be momentarily about 20 amps plus. Most pump catalogs will have the curves you need. Just call any pump supplier for direction.

Hope this helps.

Thanks to all that responeded. I really appreciate your willingness to help. I hope that in the future I will be able to offer you all advice as well.

Sincerely