HOW DO YOU START A TRASH/WATER PUMP?

[JHFV]

I got a pump to pump water out of my pond and i cant figure out how to get the thing started. i filled up the bell housing full of water and then laid the hose in the water and it would never start up. the engine runs fine. what am i not doing right?

 

[shaley]

Do you have a rigid hose on the suction side with a strainer?

 

[Travelover]

Frequently the problem is a tiny leak on the intake side. Check carefully. Could also have a bad seal on the impeller shaft.

 

[scott_vt]

Mornin JHFV,
As Steve stated allready you need hard suction on the intake side along with a strainer and you need a good seal between the pickup hose and the pump ! As you stated, you need to fill the pump cavity with water before starting and have someone put their hand over the discharge hose while starting, this also seems to help obtaining a prime !

 

[JHFV]

Yes i have the rigid hose with a strainer. where the hose goes into the pump a little bit of water drips there. could this be a problem?

 

[Highbeam]

Does the pump empty out your prefilled bell housing? How long is the pickup hose?

I rented a trash pump to drain a pond and foun that placing the pump near the pond made it easier to get started. Less vertical pumping I suppose. Once the pump was pushing water it really moved a lot of water fast. The engine will lug down when it starts working.

The reason I had to restart the pump several times is that the strainer kept getting clogged with salamanders. Those guys were having a bad bad day.

 

[RonMar]

Is there a foot valve incorporated into the strainer on the end of the suction line? IF not and you are trying to lift water, you probably need one. You need to fill the entire suction line with water and the foot valve(a large bore flapper check valve) allows this by keeping the fill water poured in at the pump from running back into the pond. Just like a siphon won't work with air in the line, a pump will also quit with too much air in the line. Any air in the line will stretch instead of transfering the suction force to the water below it. This air will stretch till it reaches the pump impeller then you will loose any suction you did have as the pump impeller spins in air. Like any hydraulic system, it is far easier to draw air in thru a leak than to suck fluid thru a line so the suction line must be airtight.

I used to set up emergency pumps onboard ship and we would accomplish the suction line prime in one of 2 ways. With a line attached to the top of the suction hose(where it attaches to the pump inlet), we would throw the whole suction line over the side and allow it to submerge and fill, then we would pull up the suction hose(full of water, held there by the foot valve) and connect it to the pump. The pumps we used had a small hand suction pump to finish lifting water up the suction line to fill the pump housing and finish the prime. Any leak where the hose met the pump and you couldn't finish the prime with the hand pump. These pumps also had a large funnel fitting on the pump body with a sealable hatch. You could drop a bucket on a line over the side and fill the pump and line down to the foot valve using buckets poured down thru this funnel. Any significant air leak in the line or trapped airpocket that reached the pump, and the pump would loose prime...

 

[orezok]

One of the tricks we use is while you prime it, stand on the discharge hose as close to the pump as you can (assuming it's the flexible type like fire hose). Then start the pump while still standing on the hose. As it starts to pump, it will lift your foot due to pressure and then work normally. If you don't do this, it simply pumps the prime into the discharge hose.

 

[cp1969]

As said, you can't have any leaks on the suction side. You can have all the leaks you want on the pressure side but the suction side can't tolerate much, if any.

Also, it takes some time for the pump to prime if you're lifting any distance. It takes about 60-70 seconds for mine to start pumping when I'm loading water out of the creek and that is only a lift of about six feet.

 

[Egon]

If the suction has a foot valve you may get it to pick up suction by moving the suction line up and down in the water. Acts like a pump and may help. The air on the connection is a very possible thing preventing pickup.

 

[tommu56]

Put your ear to hard sleeve and listen for air gurgling most of the time you can hear leak a lot of time these pumps have pipe thread fittings on them make sure there is no slop in in them when tightened and there is usually a gasket in the female swivel end to seal it to the male end on the pump.

Take discharge hose off while running and seal end of fitting with your hand does it build any pressure.

Take the strainer off the end of hose again cover with your hand carefully to check for vacuum.

There is usually a flapper(check valve) in the suction of the pump make sure its free.

How much lift do you have on suction side the close pump inlet is to source the pump will me more efficient.

if all else fails you can jury rig a shop vac to discharge turn it on and it should evacuate air and fill pump with water through hard sleeve. just be ready to remove vac when pump starts pumping.

tom

 

[Steve_Miller]

Trash pumps generally aren't self primers, so like a few others noted, you will need a foot valve and then also fill the hose and the bell.

Steve

 

[Skyco]

How high above the water is the pump? Generally you can't suction water more than about 26 ft, even though you could pump it hundreds of feet up on the discharge side. And that's at sea level, the higher in elevation the less distance you can suction the water.

 

[cp1969]

Trivia - Why is 26(or so) feet the limit? The water boils if you try to lift it higher.

 

[Skyco]

What you are really doing with suction is removing the air allowing atmospheric pressure to "push" the water up. Atmospheric pressure at sea level is 14.7 psi so that is all the force the suction side of a pump can produce. 14.7 psi can only lift water about 26-30 ft so that's all you got to work with on the suction side.

 

[wushaw]

Do you have a screen on the end of the suction hose?
Is the hose end in a five gallon bucket....keeps trash/mud from clogging up the screen.
How big is your trash pump?
If it's not atleast a four inch model you will be there a long time draining your pond. Mine takes all day for my small ft. pond with a 2" trash pump. It is nowhere near the size of your pond.

 

[JHFV]

It is a 1 1/2" pump. Wushaw if you have time can you come over and help me get it going?

 

[Highbeam]

I've never used or seen a trash pump used with a foot valve on the strainer end. It's gotta be an air leak.