Traveller
Member
I have a customer who has asked me to install a 3 hp sprinkler pump in the pumphouse above his well. The well is made from a vertical piece of 4' dia. culvert. I measured the distance from the pump intake to the water as 20'. The customer wishes to supply domestic water to a large shop and office plus water to a 1.5" firehose connection installed for the purpose of washing mud from logging equipment; hence, the larger size of the pump. There is a large (15' long) propane tank in the pumphouse that is used as a pressure tank. I assume one of the mechanics there regularly pumps compressed air into this tank to replenish the air volume. I noticed there seemed to be a lot of burned out pumps and pressure switches collected in the back of the pumphouse.
I am accustomed to installing jet pumps in the 1/2 to 3/4 hp range in wells where the water table is much closer to the surface and have never attempted to install a sprinkler pump as a well pump. The customer requested a cut-in pressure of 40 psi and a cut-out pressure of 60 psi. I connected the pump intake (2") to the 2" suction line there with foot valve and strainer mounted at the bottom. I filled the pump and suction line and observed the water to not be dropping. As a precaution, and to facilitate setting the pressure switch without having to fill the large propane tank, I temporarily installed a smaller (3' diameter) bladder tank on the delivery line from the pump and installed the pressure switch within 2' of it. I then shut the gate valve off that led to the large tank.
When I turned the pump on, the gauge immediately went up to 45 psi but then very quickly dropped to 22 psi. I assumed it would stay at this pressure for a bit, as the bladder tank filled, and then slowly begin to climb. This was not the case as, long after the bladder tank should have filled, the pressure still stood at 22 psi. I drained the pressure several times and checked to see if the pump was still primed, which it was. When the pump began to get quite warm to the touch, I shut the pump off.
My question is, am I asking this sprinkler pump to do something it was never designed for? The manual that came with the sprinkler pump claimed that it would pump water from a source 25' below it. If this were true, why would they bother making jet pumps if these sprinkler pumps could do the same job?
Thank you in advance for any help you can offer.
I am accustomed to installing jet pumps in the 1/2 to 3/4 hp range in wells where the water table is much closer to the surface and have never attempted to install a sprinkler pump as a well pump. The customer requested a cut-in pressure of 40 psi and a cut-out pressure of 60 psi. I connected the pump intake (2") to the 2" suction line there with foot valve and strainer mounted at the bottom. I filled the pump and suction line and observed the water to not be dropping. As a precaution, and to facilitate setting the pressure switch without having to fill the large propane tank, I temporarily installed a smaller (3' diameter) bladder tank on the delivery line from the pump and installed the pressure switch within 2' of it. I then shut the gate valve off that led to the large tank.
When I turned the pump on, the gauge immediately went up to 45 psi but then very quickly dropped to 22 psi. I assumed it would stay at this pressure for a bit, as the bladder tank filled, and then slowly begin to climb. This was not the case as, long after the bladder tank should have filled, the pressure still stood at 22 psi. I drained the pressure several times and checked to see if the pump was still primed, which it was. When the pump began to get quite warm to the touch, I shut the pump off.
My question is, am I asking this sprinkler pump to do something it was never designed for? The manual that came with the sprinkler pump claimed that it would pump water from a source 25' below it. If this were true, why would they bother making jet pumps if these sprinkler pumps could do the same job?
Thank you in advance for any help you can offer.
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