Is 50 HP really 50 HP?

Ron50 · Dec 13, 2015

Thanks for the replies. I didn't view the situation from the perspective of "work" being done, only that I wasn't pushing very far or lifting very high. Didn't really consider volumn.

npalen · Dec 13, 2015

jenkinsph said:
While it may seem strange to add a restriction it can work. Squirrel cage blower fans require a slight restriction to operate correctly in most cases.

OP here and, no, I don't mind this discussion "going electric". I really didn't say, in the topic, what kind of fuel was being used to generate the HP. But I do understand about hijacking a thread and try not to do it--not very often at least.
With that said, I run a submersible well pump and put an ampmeter on the line years ago to verify that it drew almost zero amps when the output flow was shut off. This lets me by without a pressure tank etc. for my manual underground sprinkler system and can let the pump running (on a timer) when switching between various faucet outlets on the system. At first I was worried about the pump over heating but then it is water cooled, right?

jaydee325 · Dec 13, 2015

If a centrifigual pump is run dead headed, no work is being done (no fluid moved). The energy put into the system is converted to heat since it it not performing work to move the fluid. If left for a long period of time, flashing in the pump will occur and damage results. Short periods of dead head operation is not usually detrimental.

In some large pumps, it is preferable to start the pump with the discharge valve closed as this will limit the duration of the electric current in-rush peak. Once current stabilizes, the discharge valve is slowly opened. Current will be observed to rise from the no flow value until the pump flow and head stabilizes on the pump curve.

npalen · Dec 13, 2015

jaydee325 said:
If a centrifigual pump is run dead headed, no work is being done (no fluid moved). The energy put into the system is converted to heat since it it not performing work to move the fluid. If left for a long period of time, flashing in the pump will occur and damage results. Short periods of dead head operation is not usually detrimental.

In some large pumps, it is preferable to start the pump with the discharge valve closed as this will limit the duration of the electric current in-rush peak. Once current stabilizes, the discharge valve is slowly opened. Current will be observed to rise from the no flow value until the pump flow and head stabilizes on the pump curve.

What is meant by "flashing in the pump"?

jaydee325 · Dec 13, 2015

npalen said:
That is meant by "flashing in the pump"?

As in water "flashing" to steam.

jenkinsph · Dec 14, 2015

You can operate a sprinkler system with a well pump and it is preferred to set it up for a continuous run for the entire cycle. The sprinkler zone valves will switch fast enough to sequence through the system without issue. You should take the time to balance out each zone in the system to insure that the flow rate in gpm and the operating pressures are the same for all zones. Adjust the time each zone is on to fit the water needs of each zone. You don't want to exceed the well's flow rating while in this continuous run either. Optimum would be highest gpm delivery at the lowest pressure that works well for your sprinkler spray patterns. That puts the most water on the lawn at the lowest electric costs and is the less affected by wind too. Higher delivery pressures cost more to operate and this can add up fast.

npalen · Dec 16, 2015

Mine is a "poor mans sprinkler system". The 20,000 sq ft lawn is plumbed with 3/4" PVC about a foot down. At each sprinkler is a manually operated valve in a small covered valve box. The only thing "automatic" is that I don't have to drag garden hose to set up sprinklers.
There is some advantage to this type of system on windy days as sprinklers can be turned on in areas that won't drift onto the street. Also the valve can be adjusted to reduced output on windy days to minimize wind drift.
Winterizing the system consists of connecting compressed air to pressure the system and then opening valves at strategic locations to purge the water from the pipes.

npalen · Dec 16, 2015

Mine is a "poor mans sprinkler system". The 20,000 sq ft lawn is plumbed with 3/4" PVC about a foot down. At each sprinkler is a manually operated valve in a small covered valve box. The only thing "automatic" is that I don't have to drag garden hose to set up sprinklers.
There is some advantage to this type of system on windy days as sprinklers can be turned on in areas that won't drift onto the street. Also the valve can be adjusted to reduced output on windy days to minimize wind drift.
Winterizing the system consists of connecting compressed air to pressure the system and then opening valves at strategic locations to purge the water from the pipes.