Pump Help

alex trent · July 18, 2012, 08:33:52 PM

Trying to pump water from a 4 foot deep cistern tank.. Pump inlet 4 feet below pump level. Right now a foot of water in the cistern, so the suction head is 3 feet.

Outlet will be 30 feet higher than pump and 200 feet away.

1" PVC into pump and 1' out with reducer to 1/2" for the trip up to the other storage tank.

Primed it and no suction. Fittings are tight.

Took pump off and ran the intake horizontal with the inlet inn the pump...pumps. With just a bit of a drop, even after it is pumping..stops pumping.

Do I have "no lift" pump, or is there another possibility. It is an Italian pump and the directions look generic to several pumps and on line is no help.

There are Hmin, Hmax and h symbols on the pump...and if one is suction I am well within limits.

Anyone know of a reasonably priced sump pump that will lift 40 feet. This is a situation that calls for this...the current problem aside.

glenn kangiser · July 18, 2012, 10:30:41 PM

Foot valve on the bottom to keep from losing prime?

Other than that it sounds like a possible leak on the intake side - Did you use pipe dope or tape?

I don't know if Harbor Freight ships there.

WW Grainger has about anything but not especially reasonable -

Possibly Northern http://www.northerntool.com/shop/tools/category_water-pumps Possible better quality than Harbor Freight.

July 19, 2012, 05:23:40 AM

It is all taped well at the screw ins and the PVC is glued tight.

Have a foot valve and a check valve.

Took the foot valve off, as thought it might not be opening...did not help. In any case, I am not even to the stage of losing prime as I cannot get any water into the pump from the tank.

Question...is the prime water supposed to fill the entire intake pipe down to the tank water level or just the pump section? The instructions say to use a check valve on the intake which prevents water from flowing back into the intake line.

alex trent · July 19, 2012, 10:11:42 AM

is it possible I am not waiting long enough to get air out of suction line?

It is 1" and 6 feet long.

I do see some frothy water on the discharge...I figure that is the air coming out of the suction.

I let it run 2 minutes .....afraid to burn pump with no water through it, but maybe if water in the prime OK?

rick91351 · July 19, 2012, 11:54:34 AM

What does your pump call for in the intake side? One inch sounds pretty small. I have found however the problem is more than likely on the output side of the pump. Do you have water exiting the pump?

My irrigation pumps are like 2 inch in and 1.50 inch outlet. I burned one up the other day. I went to the pump store and they gave me class on pumps. I knew I did something wrong and hopefully they gave me an answer...... I as well had a heck of a time getting it to primp and pump. They showed me I need to come back out of the outlet and waste the excess water back to the cistern rather let it build head pressure and this builds heat in the pump and motor.

I am very concerned with 200 feet of half inch if I am reading this right? With thirty feet of rise? That is a lot to be asking, there is a lot of resistance and friction there unless that is how your pump is specced out. But I only had one mini class at the pump store.

July 19, 2012, 12:15:06 PM

What type of pump is it ?

Hmin and Hmax is min and max head at the intake

You will have negative H if your trying suck from below

A positive displacement pump will suck to some extent

a rotary vane type- needs to be at or below the intake level- ie the intake side is pressurised by the head of the tank

alex trent · July 19, 2012, 12:45:01 PM

Thee is very little info with the pump...booklet with it is for multiple Pumps, not specific to this one.

All specs are on the pump and one chart on box.

In addition to the min and max it has another H (no other mark) which is labeled 35-9.

This has a prime hole so i expect it is not rotary vane and needs to be below water...I hope.

The intake hole is 1 " so I have 1' pipe.

Likewise on output...goes from 1" to 1/2.

No water exits the pump and I have it open just outside the outlet so am not yet dealing with the long push up.

1/2" is small but this is intermittent use and 250 gallons at a time from cistern to upper tank. The curve on the box says this is 6 gals a minute, so if that is the case I am fine.

How long to get water up a 1' pipe six feet? maybe i am being too quick to say not working...I waited 2 minutes??

rick91351 · July 19, 2012, 01:44:34 PM

I would make sure the lift pipe is full then reconnect. Prime the pump via the pump hole leave the out up off start pump and see if it expels water. I would think if it is going to prime and pump it will be almost instant.

alex trent · July 21, 2012, 01:04:40 PM

http://www.pacificpumpandpower.com/docs/Friction_Loss_Table.pdf

Rick..you saved me a lot of digging up pipe.

Your comment about pipe size struck a chord and when I took a look..wow.

At 5 gph 1/2 inch loses 50 feet head per 100 foot of run. 3/4 is 8 feet.

I need 40 foot lift and have 300 feet...so a 140 foot pump would not make it.

Good advice and it is not as simple as it might seem.