Leaky Boot
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825 Foot Deep Well
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Bob NH
In the Trades
I have used Dempster pumps and they are a good pump. However, their rating designations don't compare to those of other pumps.
Dempster rates the flow nearer the maximum end of the curve while Goulds rates the flow nearer the maximum efficiency point.
Dempster 10 GPM 1 HP - 5 GPM at 450 ft head; 10 GPM at 300 ft of head.
http://www.dempsterinc.com/PDF%20FIles/performance%20curves.pdf
Goulds 7GS10 7 GPM 1 HP - 5 GPM at 450 ft head; 10 GPM at 300 ft of head.
http://www.goulds.com/pdf/7310.pdf
Both good pumps; virtually identical curves; different GPM ratings.
I wouldn't put either of them in the well we are talking about. They don't deliver enough head. At 500 ft the Dempster is at shutoff head; zero flow; and that is with no pressure for the tank.
The drawdown elevation is uncertain. The owner needs a pump that will deliver water, whatever happens to the drawdown.
I would go with the Goulds 5GS15 pump at 1.5 HP. That gives the following flow and drawdown capability with 50 psi available (see Goulds link above) at the top of the well:
Drawdown = 400; 5.9 GPM
Drawdown = 500; 4.8 GPM
Drawdown = 600; 3.5 GPM
Drawdown = 700; 1.8 GPM
The Dempster X Model 5 GPM rated pump with 1.5 HP motor has virtually the same performance as the Goulds 5GS15 and would work as well.
If you want more pressure or more drawdown or more flow, use a Goulds 5GS20 2 HP pump. I didn't see a 2HP model for the Dempster.
Dempster rates the flow nearer the maximum end of the curve while Goulds rates the flow nearer the maximum efficiency point.
Dempster 10 GPM 1 HP - 5 GPM at 450 ft head; 10 GPM at 300 ft of head.
http://www.dempsterinc.com/PDF%20FIles/performance%20curves.pdf
Goulds 7GS10 7 GPM 1 HP - 5 GPM at 450 ft head; 10 GPM at 300 ft of head.
http://www.goulds.com/pdf/7310.pdf
Both good pumps; virtually identical curves; different GPM ratings.
I wouldn't put either of them in the well we are talking about. They don't deliver enough head. At 500 ft the Dempster is at shutoff head; zero flow; and that is with no pressure for the tank.
The drawdown elevation is uncertain. The owner needs a pump that will deliver water, whatever happens to the drawdown.
I would go with the Goulds 5GS15 pump at 1.5 HP. That gives the following flow and drawdown capability with 50 psi available (see Goulds link above) at the top of the well:
Drawdown = 400; 5.9 GPM
Drawdown = 500; 4.8 GPM
Drawdown = 600; 3.5 GPM
Drawdown = 700; 1.8 GPM
The Dempster X Model 5 GPM rated pump with 1.5 HP motor has virtually the same performance as the Goulds 5GS15 and would work as well.
If you want more pressure or more drawdown or more flow, use a Goulds 5GS20 2 HP pump. I didn't see a 2HP model for the Dempster.
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Mikey
Aspiring Old Fart, EE, computer & networking geek
Another ignorant question
Everyone has been talking about 1" pipe down the well, but all the Goulds pumps come with 1 1/4" discharge connections. Wazzup?
Everyone has been talking about 1" pipe down the well, but all the Goulds pumps come with 1 1/4" discharge connections. Wazzup?
Bob NH
In the Trades
They make a line of pumps with a wide range of capacity that all have the same connection. Goulds recommends 1" as adequate for up to 10 GPM.
Speedbump
Active Member
We have and use SCH 80 PVC with a male thread on one end and a female on the other. They work great and we have had no unthreading problems. As for the depth we are talking here, I can't attest to that as we don't hang pumps much deeper than 150'.
bob...
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