Karcher irrigation pump

[maltaron]

A bit of a long shot with this one. Does anyone have any knowledge of these pumps. It worked fine since bought but has been left dormant for a few months. It now will not suck even though primed correctly. I tried filling the suction pipe before fitting it to no avail. Any help would be appreciated.

TIA

 

[maltaron]

Used to draw water from river for garden watering and car wash etc

 

[jj4091]

Not 100% sure but my guess would be is that the inlet or the impellar is seized up with crud from the river. Failing that if it has been left out full of water & been exposed to freezing temps then the plastic impellar body will have cracked & be sucking in air(their pressure washers often suffer from this)

 

[maltaron]

Thanks JJ. My thoughts were as yours so I stripped it down. Everything is clean and no obvious cracks (I will recheck this for hairline cracks). The only bit that I can't get into is the inlet assembly, do you know if there is a nonreturn valve in there which may have stuck?

 

[jj4091]

Sorry don't know if there is a NRV or not, but if you have to prime it I would guess not. If the impellar is spinning freely then that is probably the place where any blockage would occour, can you run water through both ways with a hose pipe or from the tap? The pressure washers suffer leaks from hairline cracks in the cylinder head which cannot be seen with the naked eye, whether the pumps do as well I am not sure. When the pump is switched on can you feel the vibrations of the rotor turning?

 

[maltaron]

Thanks for your help JJ. The pump is thoroughly clean and water passes both ways thro' impeller and body and the motor runs fine. I suspect that there is a hairline crack as you suggest.

 

[maltaron]

Just a follow up, the pump works fine when fed in flooded mode i.e. from a water source above the pump. It looks, therefore, like a hairline crack as you suggest.

 

[maltaron]

A follow up from my January post which may help others. The problem turned out to be the inlet hose, which was a propriety reinforced plastic hose with a plastic foot valve. I had a quality brass footvalve so attached this to a 28mm copper tube with a short clear plastic hose to the pump. This is permanently in the river. The pump was primed initially about 2 mounths ago and now only needs to be switched on to work fine. It appears that the plastic footvalve was not very effective.