what pump?

what would be the type of pump to be used in lifting water up to the elevated water tank installed on the roof deck of a 5 storey building? the pump will draw water from a cistern tank about 8' in depth below the natural ground line...thanks

When you say lift, I read a jet pump but, no single line shallow well type jet pump will work for 5 stories up plus 8' deep.

So a submersible in the cistern is the only way to go unless you used a deep well two line jet pump. A submersible in the cistern is a much better way to go.

I assume gravity will feed the building but, what size tank on the roof and what is the peak demand gpm you need for the building? Also, how large is the cistern going to be and how is it going to be refilled and how frequently?

watrax said:

what would be the type of pump to be used in lifting water up to the elevated water tank installed on the roof deck of a 5 storey building? the pump will draw water from a cistern tank about 8' in depth below the natural ground line...thanks

Click to expand...

Do you want to pump up to the tank ?

>Application
-Submersible would be ideal. However, a suction lift of 8 ft is not impossible for a regular pump. Don't forget dry-run protection. (float switch? - watch out for vortex)

>Sizing
-As previously stated, you will need the max flow. Aside from that you need the total head. [8ft + (12ft x 5 stories)] Then it depends on whether the tank is open discharge or pressurized.

Operation
-how will you control the pump? Level/float switch?

With 10 GPM and a 70' head you'd need about 10(70)/40(60) = 1/3 hp.
Keeping the water velocity between 2 and 5 feet/sec in the pipe should keep friction low. Pipe friction adds to the apparent head.

I am reading this as he has a cistern in the ground with about a 10' lift to ground level and then want's to pump that up to a tank on the roof in which case a 1/3 hp shallow well pump will work though I'd use a 1/2 hp. You will need float switches to turn the pump on and off both at the cistern and the holding tank to turn the pump on and off.